The clinical problem the work targets is a familiar one in dentistry. Periodontal and peri-implant diseases destroy the alveolar bone that anchors teeth and implants, and rebuilding that bone remains one of periodontology’s hardest challenges. Guided bone regeneration, or GBR, addresses it by placing a barrier membrane over a bone defect so that fast-moving soft-tissue cells cannot invade the wound while slower osteoblasts repopulate the site and lay down new bone. Current membranes force a trade-off. Non-resorbable options such as polytetrafluoroethylene and titanium are mechanically excellent but require a second surgery to remove. Resorbable collagen membranes are more biocompatible but degrade quickly and lack strength, especially in the wet, microbe-laden environment of the mouth.

Fungal mycelium offered the researchers a way out of that trade-off. A mycelium is a dense, self-assembling network of hyphae that acts as a natural bio-adhesive, binding substrate particles together as it grows. It is intrinsically porous, a critical property for scaffolds because interconnected pores deliver nutrients and oxygen to cells and carry away waste. It is also naturally hydrophobic, thanks to mannoproteins and hydrophobins in the outermost fungal cell wall, and its chitin-containing matrix has been shown in earlier studies to promote hydroxyapatite deposition and support wound healing. The Ganoderma genus brings an additional bonus: a rich repertoire of bioactive metabolites, from polysaccharides to the immune-modulating protein LZ-8, whose components appear to work synergistically, which is why the team used the intact mycelium rather than extracted molecules.

Manufacturing the material was conceptually simple. The researchers prepared a solution of alginic acid fortified with malt extract, yeast extract and sucrose as fungal nutrients, dried it into a membrane, and immersed it in a calcium chloride bath containing hydroxyapatite nanoparticles at concentrations of 0, 1.1, 4.4 or 8.8 percent. Calcium ions crosslinked the alginate chains around the mineral particles, producing a sterilized culture substrate. A small square of G. sessile mycelium was then inoculated onto each hydrogel and incubated at 25 degrees Celsius in the dark. Photographic monitoring showed that colonization progressed at essentially the same pace on every substrate, with full coverage achieved by day twelve regardless of mineral content, suggesting the hydroxyapatite does not impede fungal growth.

A biomaterial destined for the body must be sterile and biologically inert, so the team froze the colonized membranes, freeze-dried them, and autoclaved them at 120 degrees Celsius for twenty minutes to kill the fungus. The treatment worked: when fragments were re-cultured on nutrient agar for sixty days, no growth appeared. Transmission electron microscopy of cross-sectioned hyphae confirmed the loss of cellular integrity, but with a striking qualification. The thickness of the hyphal cell walls was statistically unchanged by autoclaving, measuring roughly 77 nanometers before and after treatment, meaning the fungal cell wall scaffold survived sterilization intact even though the living contents did not. Macroscopically, the finished membrane shrank by about 21.7 percent in covered area but retained its shape, flexibility and ease of handling.

Structural analysis revealed why the material is so unusual. X-ray diffraction confirmed the presence of the synthetic hydroxyapatite, but it also detected something the researchers had not put there: calcium oxalate dihydrate crystals, which the fungus itself had precipitated from the calcium-rich medium. Ganoderma species are known to produce such crystals as a calcium reservoir, and remarkably, calcium oxalate surfaces serve as common binding sites for bone proteins such as osteopontin, which promotes osteoblast adhesion and migration. That raises the tantalizing possibility that the fungal crystals could act as anchoring points for bone proteins and even as nucleation sites for new hydroxyapatite formation inside the body. Scanning electron microscopy then showed the composite’s most compelling feature: where the mycelium had colonized the substrate, it had built a porous, hierarchical, trabecular network strikingly similar to spongy bone.

The membrane’s two faces behave almost oppositely toward water. The mycelium-rich side, studded with hydrophobic fungal proteins and covered in micrometer-scale roughness, produced a water contact angle of about 143 to 148 degrees, well into strongly hydrophobic territory. The alginate-rich side measured roughly 36 to 38 degrees, clearly hydrophilic. This anisotropy could be a design advantage rather than an accident: hydrophobic surfaces tend to resist bacterial adhesion and lend mechanical stability, while hydrophilic surfaces favor protein adsorption, cell attachment and nutrient exchange. A membrane that presents a bacteria-repelling face to the soft tissue and a cell-friendly face to the bone defect would create a more biomimetic microenvironment than any uniform material.

Mechanical testing of the lead composition, My-ALG-1.1HA, added further encouragement. Stress-strain curves showed an elastic region, a yield point and a long plastic plateau, confirming a ductile material that absorbs substantial energy before failing. The Young’s modulus came out at 25.28 megapascals, squarely within the reported range for human oral mucosal tissue of roughly 2.2 to 54.7 megapascals, although the maximum tensile stress of 0.32 megapascals remains below oral tissue values. Notably, the ductility exceeded that of previously reported mineralized mycelium materials, and the same hydroxyapatite loading that made the team’s earlier alginate-hydroxyapatite membranes brittle seemed masked by the mycelium framework. Degradation testing in simulated body fluid was equally telling: the composite lost about 49.7 percent of its weight in the first day, but the presence of fungal molecules slowed overall degradation roughly 380 percent relative to the corresponding alginate-hydroxyapatite membrane without mycelium, plausibly because mycelium-derived compounds raise hydrophobicity and shield the hydrogel from dissolution.

A first biological screen was cautiously reassuring. The researchers ground each biomaterial into powder, extracted it into cell culture medium at one milligram per milliliter, and exposed MC3T3-E1 osteoblast-like cells to the dispersions for 48 hours. Optical microscopy showed normal cell size, shape and spreading, and a crystal violet assay found no statistically significant reduction in attached cells for any formulation, including those with hydroxyapatite at 1.1, 4.4 and 8.8 percent. The authors are careful to frame this as a preliminary, indirect assessment rather than proof of osteogenic performance. They also stress the limits of the current dataset: contact angle and tensile measurements were not taken for the higher-mineral compositions, comparisons with oral tissues involve differing test geometries, and wet-state stability and suture retention still need optimization, potentially through higher crosslink density, secondary covalent networks or alginate-chitosan complexes.

Even with those caveats, the study stakes out genuinely new territory. Where most mycelium materials have been explored for packaging, construction or skin wound dressings, this work positions intact Ganoderma mycelium as a structure-directing biological framework inside a mineralized composite engineered for the mouth. Future work must move from indirect assays to direct osteoblast culture on the intact anisotropic surfaces, and on to alkaline phosphatase activity, osteogenic marker expression and mineralization, before the membrane can approach the clinic. But the core demonstration stands: a mushroom can be persuaded to grow, on demand, into a sterile, ductile, bone-like scaffold whose chemistry, topology and degradability are shaped by a living organism. If subsequent studies confirm that the fungal framework and its bioactive cargo can outperform collagen barriers in the demanding environment of a periodontal defect, the humble mycelium may earn a permanent place in the surgeon’s toolkit.

Subject of Research: A mycelium-alginate-nanohydroxyapatite composite biomaterial for guided bone regeneration

Article Title: Characterization of a novel biomaterial obtained by culturing Ganoderma sessile on a substrate composed of hydroxyapatite nanoparticles and alginate with potential for bone tissue regeneration

Article References: D’Elía, N. L., Postemsky, P., Sartuqui, J., Placente, D., Gonzalez-Pardo, V., Ercoli, D., & Messina, P. V. (2026). Characterization of a novel biomaterial obtained by culturing Ganoderma sessile on a substrate composed of hydroxyapatite nanoparticles and alginate with potential for bone tissue regeneration. Frontiers in Biomaterials Science, 5, Article 1895818. https://doi.org/10.3389/fbiom.2026.1895818

Image Credits: AI Generated

DOI: 10.3389/fbiom.2026.1895818

Keywords: Ganoderma sessile, mycelium, hydroxyapatite nanoparticles, alginate, guided bone regeneration, bone tissue engineering, biomaterials, periodontal regeneration, hydrophobicity, cytocompatibility, calcium oxalate, barrier membranes

The research, led by Laís Salviano de Oliveira Schiavi of the Universidade Federal de Lavras in Brazil, together with colleagues at UNESP, UFSCar, and UFLA, used plasma-enhanced chemical vapor deposition, or PECVD, to coat bleached eucalyptus cellulose fibers with thin organosilicon films derived from hexamethyldisiloxane, commonly abbreviated HMDSO. The technique is inherently solvent-free, a significant environmental advantage over conventional wet-chemical treatments such as silanization or polymeric impregnation, which often require long processing times and reagents that complicate industrial adoption. In the plasma reactor, HMDSO vapor, oxygen, and argon were introduced into a low-pressure chamber where a 13.56 MHz radiofrequency field ignited a non-thermal discharge, fragmenting the precursor molecules and depositing a nanometer-scale coating onto roughly 180 grams of dispersed cellulose pulp per run.

What makes HMDSO particularly versatile as a precursor is that the chemistry of the resulting film can swing dramatically depending on the gas mixture. With abundant oxygen, the plasma fragments oxidize into silica-like structures rich in polar Si–O bonds. With less oxygen and more precursor, methyl-containing organosilicon groups survive, producing hydrophobic, wax-like surfaces. The Brazilian team exploited this tunability by running four treatment conditions with nominal HMDSO concentrations ranging from 2.3 to 70.0 percent, labeled ORG-T02, ORG-T30, ORG-T50, and ORG-T70, while holding deposition time at 600 seconds and applied power at 100 watts so that only the precursor concentration varied. Reference films deposited on glass coverslips and polished aluminum plates confirmed the chemical progression: the lowest concentration yielded an oxidized, silica-like coating, while the highest produced a clearly hydrophobic surface with a water contact angle of approximately 109 degrees.

Crucially, the plasma treatment left the fibers themselves intact. Scanning electron microscopy showed that the characteristic fibrous morphology survived all four treatments without visible degradation, and X-ray diffraction confirmed that the crystalline structure of cellulose was preserved, with crystallinity indices hovering between roughly 78 and 80 percent across treated samples compared with 81.5 percent for untreated pulp. Energy-dispersive X-ray spectroscopy detected silicon on every treated fiber surface and none on the untreated reference, confirming that HMDSO-derived species had been deposited. In other words, the modification was strictly a surface phenomenon, exactly what a reinforcing fiber needs if its bulk mechanical contribution is to be retained during composite processing and service.

The moisture results, however, revealed that wettability and water uptake do not map onto each other in any simple linear way. After 192 hours in a nearly saturated atmosphere, the most hydrophobic treatment, ORG-T70, reduced moisture absorption by only 9.26 percent relative to untreated cellulose. The intermediate condition, ORG-T30, performed best, cutting moisture uptake by 12.20 percent, while ORG-T50 and ORG-T02 actually increased absorption by 36.91 and 43.91 percent respectively. The authors attribute this apparent paradox to the heterogeneous nature of plasma deposition on fibrous substrates: contact angle measurements probe only the local region touched by a droplet, whereas moisture absorption integrates the response of the entire fiber assembly, including coating continuity, coverage, and packing effects that a single droplet cannot capture.

To probe the molecular underpinnings of the fiber–coating interaction, the team turned to computational chemistry. Using the Quantum Theory of Atoms in Molecules, or QTAIM, framework with B3LYP calculations, they modeled a cellulose fragment approaching an HMDSO molecule at varying distances. The simulations showed no chemical reaction between the two species; instead, the most favorable configuration occurred at an intermolecular separation of about 1.67 angstroms and was dominated by hydrogen bonding between the cellulose hydroxyl group and the oxygen atom of HMDSO. The atomic properties of the interacting hydrogen satisfied the Koch and Popelier criteria for hydrogen bond formation. The authors are careful to note that this simplified model does not reproduce the full plasma environment, but it lends theoretical plausibility to an adsorption mechanism that would explain how the coating anchors to cellulose without disrupting its structure.

With modified fibers in hand, the researchers extruded fiber-cement composites containing 60 percent high-early-strength Portland cement, 33 percent agricultural limestone, 5 percent cellulose fibers, and small amounts of a methylcellulose thickener and a carboxylic polyether rheology additive. Extrusion, which compacts the material and aligns fibers along the flow direction, was chosen for its ability to produce dense specimens at low water-to-cement ratios. Before any mechanical testing, the team verified that the treated fibers would not sabotage cement curing: using the Hofstrand inhibition index, every formulation scored far below the 10 percent threshold that signals problematic hydration inhibition, with values between roughly 0.18 and 0.40 percent. The plasma coatings, in short, did not interfere with the chemistry that turns cement paste into solid matrix.

The decisive test came after accelerated aging. Specimens cured for 28 days were subjected to repeated cycles of 8 hours of UVA exposure at 365 nanometers followed by 4 hours of moisture conditioning, a protocol adapted from ASTM G154-23, and then retested after 10 and 20 cycles. The results overturned the hydrophobicity hierarchy. After 20 cycles, composites reinforced with fibers treated under the ORG-T02, ORG-T30, and ORG-T50 conditions showed modulus of rupture values 22.54, 38.01, and 6.62 percent higher, respectively, than the composite made with untreated fibers, while the most hydrophobic formulation, F70-ORG, fell 9.19 percent below the untreated reference. Modulus of elasticity followed the same pattern, with F30-ORG 37.72 percent above the untreated composite and F70-ORG 9.75 percent below, and toughness told a similar story, with F02-ORG and F30-ORG exceeding the aged untreated reference by 57.14 and 42.85 percent.

The fate of the highly hydrophobic F70-ORG formulation is particularly instructive. At 28 days, before any aging, it posted the best moisture-related numbers of the batch, with apparent porosity reduced by 20.67 percent and water absorption by 24.43 percent relative to the untreated fiber composite. Yet those gains evaporated under cyclic conditioning, and by 20 cycles the formulation was mechanically underperforming the untreated control. Maximum hydrophobicity, the study concludes, does not correspond to the best composite response. The authors caution that repeated moisture exposure allows continued hydration of residual cement phases, which may densify the matrix and complicate the interpretation, and that no direct interfacial adhesion measurements were performed, so the differences after aging cannot be attributed exclusively to fiber modification. All composites nonetheless remained within the water absorption limits of the Brazilian standard NBR 7581-2 for corrugated fiber-cement products.

The broader significance of the work lies in its reframing of a design assumption. Rather than chasing ever-lower water contact angles, the results suggest that intermediate surface conditions, exemplified by ORG-T30, strike a more favorable balance between moisture protection and whatever interfacial interaction the fibers retain with the cementitious matrix. Because PECVD is solvent-free, fast, and tunable through gas composition alone, it offers the construction industry a scalable route to upgrading a renewable reinforcement that has been hampered by durability concerns for decades. The authors emphasize that their 20-cycle protocol is a comparative tool rather than a predictor of field service life, and that longer exposures plus direct interface characterization will be needed to confirm how persistent the benefits are. Even so, the message is clear and likely to resonate across materials science: when it comes to protecting natural fibers in cement, moderation beats extremes.

Subject of Research: HMDSO plasma modification of cellulose fibers for improving the water resistance and mechanical durability of extruded fiber-cement composites

Article Title: HMDSO plasma treatment of cellulose fibers influences water resistance and mechanical performance of extruded fiber cement composites

Article References: HMDSO plasma treatment of cellulose fibers influences water resistance and mechanical performance of extruded fiber cement composites. (n.d.). https://doi.org/10.1007/s44508-026-00025-8

Image Credits: AI Generated

DOI: 10.1007/s44508-026-00025-8

Keywords: cellulose fibers, HMDSO, plasma treatment, PECVD, fiber-cement composites, hydrophobicity, moisture absorption, accelerated aging, modulus of rupture, cement hydration, organosilicon coatings, construction materials

The stakes are larger than they might appear. As electricity generation expands to meet the demands of inclusive and sustainable societies, high-voltage network infrastructure has accelerated remarkably, and overhead transmission remains far more cost-effective than burying cables underground, a point reinforced by an April 2025 report from the Institution of Engineering and Technology. Insulators in these lines do double duty: they bear mechanical loads while providing sufficient electrical insulation between live conductors and supporting structures. Ceramics and glass once dominated, but polymer composites have steadily displaced them thanks to their low weight, hydrophobicity, breakdown strength, corrosion resistance, low cost, and ease of handling and installation. A composite insulator consists of three sections—a core rod, the housing or weather sheds, and end fittings—and it is the housing that most often determines whether the device survives decades outdoors.

The review highlights data from the International Council on Large Electric Systems (CIGRE) showing that the failure rate of high-voltage composite insulators is driven largely by degradation of the housing and shed. Aging manifests as chalking or powdery surfaces, damage, loss of hydrophobicity, poor mechanical strength, and reduced electrical breakdown strength. Because sheds face environmental, mechanical, electrical, and thermal stress simultaneously, the authors note that shed failure is reportedly inevitable over time, making material improvement the central battleground. Silicone rubber and EPDM have attracted the most attention as matrix materials, and the review systematically examines how each performs and how each can be strengthened.

Silicone rubber is an unusual polymer. Derived ultimately from sand or quartz, it features an alternating silicon-oxygen backbone rather than the carbon-carbon chains of organic rubbers, making it a hybrid organo-silicon material. In high-voltage insulation, the workhorse formulation is based on polydimethylsiloxane, prized for its hydrophobic, water-repellent character. Crucially, SIR can recover hydrophobicity between contamination events and corona exposure, a self-healing surface property that other materials lack. Yet the review stresses that SIR is not invulnerable: silicon-carbon bonds are weaker than the Si-O-Si backbone, opening the door to hydrolysis, oxidative degradation, and photocatalytic degradation under harsh conditions, while ultraviolet radiation can break bonds, lower surface resistance to moisture, and raise leakage currents.

The evidence that fillers can transform SIR is striking. In one study cited by the review, Aiman and colleagues subjected high-temperature vulcanized SIR hybrid composites loaded with nano-silica and micro alumina trihydrate to 900 hours of multi-stress aging. The composite with 6 weight percent SiO2 achieved a direct-current resistivity of about 532.6 × 10^13 ohm-meters at 60 degrees Celsius before aging, with only an 18.5 percent reduction afterward, and maintained the smallest leakage current among all samples. Beyond that optimum, particle agglomeration and poor dispersion degraded performance—illustrating a recurring theme: more filler is not always better. In related work, Wang and colleagues anchored TiO2 nanoparticles onto talc nanoplatelets via a dehydration reaction, producing composites with more uniform particle dispersion and improved breakdown strength, while Mahendra and colleagues found that adding 2 weight percent Al2O3 and 1 weight percent boron nitride to room-temperature vulcanized SIR delayed thermal degradation by roughly 20 degrees Celsius and boosted flashover voltage by 40.5 percent under salt-fog testing of heavily polluted surfaces.

Other SIR studies reinforce the pattern that optimal loading is a narrow target. Rehman and colleagues found that 3 weight percent nano-TiO2 preserved the highest direct-current resistance—from 482.5 down to 198.7 gigaohms even at elevated temperature—while 3 and 5 weight percent loadings showed the best hydrophobicity, attributed to low surface energy, non-polar methyl groups, and surface roughness that hinder water ingress. Ahmed and colleagues observed that dielectric strength in silica-filled HTV-SIR rose with filler content up to 30 weight percent, beyond which conduction paths formed between particles and breakdown strength fell. Hybrid approaches also shine: composites with 4 weight percent nano-SiO2 and 20 weight percent micro-Al2O3 delivered optimal dielectric breakdown strength before and after aging, and a 15 weight percent ATH@SiO2 hybrid in RTV-SIR achieved surface resistivity of 8.4 × 10^14 ohm-centimeters, breakdown strength of 190 kilovolts, and improved tracking resistance.

EPDM tells a parallel story with its own chemistry. Introduced into high-voltage insulator technology some 45 to 50 years ago, this elastomer owes its outstanding environmental resistance to low unsaturation in the parent polymer chain, giving it chemical and weather resistance along with strong thermal and electrical properties. Rizwan and Chandan compared magnesium hydroxide and alumina trihydrate fillers in EPDM and found that Mg(OH)2 composites showed better interfacial interaction, yielding superior tensile strength, thermal stability, and hydrophobicity, while 60 weight percent ATH delivered maximum dielectric breakdown strength. Park and Lee explored a three-component system of surface-modified nano-SiC within micro-SiC/EPDM, where vinyl-functionalized nanoparticles bonded to the matrix through hydrosilylation; adding 2.0 grams of nano-SiC distributed space charge evenly and raised breakdown strength, but beyond that threshold conductive passages formed and performance dropped. Eliyan and colleagues showed that gamma radiation improved ZnO/EPDM dispersion and cross-linking, with tensile strength and dielectric strength peaking at low loadings of 0.1 to 0.3 weight percent.

Hybrid and blended systems are emerging as a particularly promising frontier. Rizwan and Chandan’s accelerated aging work—exposing composites to high temperature, ultraviolet radiation, and acid rain—showed that Mg(OH)2/EPDM composites loaded with TiO2 nanoparticles reached a contact angle of 110 degrees, far above pure EPDM’s 83.6 degrees, because TiO2’s photostability and low surface energy improved matrix interaction, whereas boron nitride, intrinsically partially hydrophilic, left contact angle unchanged. Blending the two rubbers themselves also pays dividends: Alber and colleagues found that a 75 weight percent EPDM, 25 weight percent SIR blend achieved a breakdown strength of 19.61 kilovolts per millimeter, versus 12.89 for the inverse ratio, though tensile strength favored the SIR-rich blend at 3.54 megapascals. Bazli and colleagues similarly reported that EPDM blended into SIR raised dielectric breakdown strength by trapping charge carriers, effectively impeding electrical failure.

The review does not shy away from the field’s persistent problems: filler agglomeration, surface property degradation, corrosion, leakage current, flashover, and discharge all shorten insulator service life, and polymer insulators remain vulnerable to aging under ultraviolet radiation and extreme weather. The authors’ prescriptions are forward-looking. They recommend response surface methodology with central composite design to optimize processing parameters and cost—an approach not yet applied to insulator shed materials—alongside 3D turbula dispersion and sintering techniques to combat nanoparticle agglomeration. They propose fabricating SIR and EPDM composites reinforced with electrical-corrosion-resistant glass nanoparticles, which offer superior dielectric performance, boron-free chemical durability, and high mechanical reinforcement, and they call for wear characterization, long-term dielectric breakdown simulation using COMSOL Multiphysics, and machine learning as a predictive tool. For a component the public rarely sees, the humble rubber shed is suddenly at the center of a materials revolution—and the grid’s reliability may depend on getting every weight percent right.

Subject of Research: Silicone rubber and EPDM composites reinforced with inorganic fillers for high-voltage power transmission insulator sheds

Article Title: Silicone and EPDM rubber-based composites for high-voltage power transmission insulator sheds: a review

Article References: Ogbonna, V., Popoola, O., & Popoola, P. (2026). Silicone and EPDM rubber-based composites for high-voltage power transmission insulator sheds: a review. Polymer Bulletin, 83(12), Article 676. https://doi.org/10.1007/s00289-026-06737-3

Image Credits: AI Generated

DOI: 10.1007/s00289-026-06737-3

Keywords: silicone rubber, EPDM, composite insulators, high-voltage insulation, nanofillers, hydrophobicity, dielectric breakdown, leakage current, flashover, polymer composites, insulator sheds, aging degradation

Ion-selective electrodes are the quiet workhorses of modern analytical chemistry. The glass electrode that measures pH in every laboratory, the chloride probes monitoring water treatment plants and the wearable patches that read electrolytes from sweat all rely on the same principle: a selective membrane binds a target ion, and the resulting charge imbalance generates a voltage that can be read out with exquisite precision. In classical designs, that voltage was measured against an internal reference solution and a silver-silver chloride wire, an arrangement that delivered superb stability but made the electrodes bulky, fragile and impossible to miniaturize into flexible, wearable or disposable formats.

The all-solid-state approach eliminates the inner filling solution altogether, replacing it with a solid transducing layer that sits between an electronic conductor and the ion-selective membrane. This layer must perform a deceptively difficult trick: convert an ionic signal, the accumulation of charged species at the membrane interface, into an electronic signal that a circuit can read, without losing charge, drifting in potential or admitting water. Graphene and carbon nanotubes have dominated this role for over a decade, prized for their conductivity and high surface area. Yet, as the Shenzhen team notes, their intrinsic microstructures impose real limitations, and the field has been actively searching for alternative carbon architectures that can break through these performance bottlenecks.

The researchers’ answer begins with ZIF-8, a metal-organic framework built from zinc ions bridged by imidazolate linkers into a zeolite-like lattice riddled with uniform pores. Metal-organic frameworks have become favorite sacrificial templates for functional carbons because their atomic-scale architecture is inherited by the carbon product: heat the framework under the right conditions and the organic linkers carbonize while the metal nodes catalyze pore formation, leaving behind a three-dimensional sponge of carbon with enormous internal surface area. What distinguishes the new work is the atmosphere chosen for this transformation. Rather than the conventional inert or nitrogen-only pyrolysis, the team synthesized their nanoporous carbon under a mixed nitrogen-hydrogen atmosphere, a choice that proved central to the material’s final properties.

That processing route delivered three attributes simultaneously, each addressing a specific failure mode of solid-contact electrodes. First, the resulting carbon possesses a high specific surface area, providing abundant sites for charge accommodation. Second, the material is nitrogen-doped, and those nitrogen sites contribute to a robust electric double-layer capacitance, the mechanism by which the transducing layer stores ionic charge at its surface without any Faradaic reaction. A high double-layer capacitance is the key to a stable electrode potential: the more charge the interface can buffer per unit of potential change, the less the measured voltage drifts when the membrane is perturbed by current leakage or sample fluctuations. Third, and perhaps most ingeniously, the carbon is strongly hydrophobic, achieved by minimizing the polar oxygen-containing functional groups that conventional oxidation treatments tend to leave on carbon surfaces.

Hydrophobicity matters because of a phenomenon known as the water layer problem. When a hydrophilic solid contact touches an aqueous sample, water molecules and dissolved ions can infiltrate the interface between the transducer and the ion-selective membrane, forming a thin, ill-defined aqueous film. This hidden layer acts as an uncontrolled reservoir of ions and a site for parasitic reactions, producing slow potential drift, hysteresis when the sensor is cycled between different concentrations, and degraded long-term stability. By keeping the interface dry, the hydrophobic ZIF-8-derived carbon suppresses water layer formation at its source, which the team identifies as the mechanism underpinning the enhanced sensitivity and long-term stability of their devices.

The electrochemical results for sodium sensing are striking. The electrodes exhibited what the authors call Super-Nernstian sensitivity, reaching 64.11 millivolts per decade of sodium concentration. The Nernst equation dictates that an ideal monovalent ion electrode should respond at roughly 59.2 millivolts per decade at room temperature, so a slope above that value is more than a benchmark of quality; it signals that the transduction process is unusually efficient, with the capacitive interface converting membrane charge into potential with minimal loss. The electrodes also achieved a detection limit of 10 to the power of minus 4.7 molar, corresponding to the low tens of micromolar range, sufficient for physiologically relevant sodium measurements in matrices such as sweat, where concentrations typically sit in the tens of millimolar range and a comfortable margin below the detection limit is desirable.

According to the team, the resulting solid-contact ion-selective electrodes outperform most reported solid transducing materials, a claim that carries weight given the crowded field the work enters. The literature the authors survey spans carbon black loaded with platinum nanoparticles, three-dimensionally ordered macroporous carbons, vertically aligned graphene substrates, conductive metal-organic frameworks and MOF-derived porous carbons tailored for wearable sweat analysis. Each of these platforms has chipped away at the drift, sensitivity and stability problems of solid-contact electrodes, but few have combined high capacitance, deliberate hydrophobicity and a scalable synthesis route in a single material. The integrated design strategy, in which one synthesis step delivers surface area, nitrogen doping and water repellency at once, is what the authors present as the pathway’s principal advantage.

The broader significance extends well beyond sodium. Solid-contact ion-selective electrodes are the sensing backbone of an emerging generation of wearable health monitors that read electrolytes from sweat in real time, of point-of-care diagnostic cartridges, and of environmental sensors deployed for continuous water quality monitoring, including agricultural systems that track irrigation water over long periods. Sodium itself is a analyte of genuine clinical interest, since sweat sodium loss is a hallmark of cystic fibrosis screening and a key metric for athletes at risk of hyponatremia. A transducing layer that improves sensitivity while resisting the moisture-driven drift that plagues sensors worn against perspiring skin could therefore ripple through multiple application domains, and the same ZIF-8-derived carbon chemistry could in principle be paired with membranes selective for potassium, calcium, chloride or other ions.

The Shenzhen group, affiliated with the university’s Key Laboratory of Flexible Printed Electronics Technology and its School of Materials Science and Engineering, has a track record in this space, including earlier work on ZIF-67-derived cobalt-carbon composites whose pseudocapacitance similarly boosted solid-contact electrode performance. The new study, published on 15 September 2026 and funded through Shenzhen’s science and technology innovation programs, refines that philosophy: rather than adding redox-active components, it engineers the carbon itself, using the ZIF-8 template and a hydrogen-containing atmosphere to strip away the hydrophilic oxygen groups that undermine stability. As wearables and continuous monitors demand sensors that stay calibrated for days rather than hours, materials that keep the solid contact dry, capacitive and defect-tolerant may prove to be the quiet enablers of the next wave of electrochemical diagnostics, one nanopore at a time.

Subject of Research: ZIF-8-derived hydrophobic nanoporous carbon as a solid transducing layer for high-performance all-solid-state sodium ion selective electrodes

Article Title: A ZIF-8 derived nano-porous carbon as solid transducing layer in high-performance all-solid-state sodium ion selective electrodes

Article References: Wang, P., Fan, S., Liu, H., Zhou, S., Luo, J., Meng, Y., Ning, J., Yu, S., & Wei, J. (2026). A ZIF-8 derived nano-porous carbon as solid transducing layer in high-performance all-solid-state sodium ion selective electrodes. Ionics. https://doi.org/10.1007/s11581-026-07510-2

Image Credits: AI Generated

DOI: 10.1007/s11581-026-07510-2

Keywords: ion-selective electrodes, ZIF-8, nanoporous carbon, metal-organic frameworks, solid-contact transducers, sodium sensing, double-layer capacitance, hydrophobicity, potentiometric sensors, wearable sensors, electrochemistry, nitrogen doping

The study, published in Advanced Composites and Hybrid Materials, was led by Hui Gao, Yunli Wang, Ke Pei, and Weilin Xu, with colleagues at Wuhan Textile University and Hubei University. The researchers describe a hierarchical, bioinspired assembly process that builds up color and protection on basalt fiber fabrics in three deliberate stages. First, silk fibroin, the protein extracted from silkworm cocoons, is converted into nanoparticles and deposited onto the fiber surface. Then the coated fabric is dyed with an acid dye in an ethanol-water mixture. Finally, a thin layer of polydimethylsiloxane, a flexible silicone polymer, is cured onto the surface at high temperature, sealing the color system beneath a hydrophobic armor. The resulting material, which the team abbreviates PDBS, combines vivid coloration with remarkable resistance to thermal shock and ultraviolet radiation.

The choice of silk fibroin as an intermediate layer is the conceptual heart of the work. Silk proteins are famous for their mechanical toughness and their ability to self-assemble into ordered structures, and materials scientists have increasingly looked to silk as a sustainable building block for functional coatings. In this study, the researchers used a technique called non-solvent induced phase separation to force dissolved silk fibroin out of solution and into discrete nanoparticles. When the conditions are tuned correctly, these nanoparticles deposit uniformly onto the basalt fiber surface, creating a protein-rich layer that is far more receptive to dyes than the bare, chemically inert glass. The layer essentially gives the volcanic fiber a biopolymer skin that behaves like the protein fibers found in conventional textiles.

Getting that deposition right required careful optimization. The team found that the concentration of silk fibroin in the processing solution played a decisive role in how well the nanoparticles adhered to the basalt fibers. At a concentration of 60 percent by weight, the deposition reached its optimum, producing a coating dense and uniform enough to anchor the subsequent dye chemistry. Below that level, the protein layer was too sparse to provide adequate binding sites; above it, the solution properties apparently worked against clean, even deposition. This kind of concentration-dependent behavior is typical of phase separation processes, where the balance between nucleation, growth, and aggregation of the polymer determines the final morphology of the coating.

With the silk nanoparticle layer in place, the researchers turned to coloration. Acid dyes are water-soluble anionic dyes that bind strongly to protein fibers through ionic interactions, which is why they are the standard choice for wool and silk textiles. Basalt fibers, being essentially mineral glass, offer no such binding chemistry, but the silk fibroin coating restores it. The team carried out the dyeing in an ethanol-water system and systematically varied the ethanol content, discovering that color strength peaked when the solvent mixture reached 98 percent ethanol. The ethanol-rich environment appears to promote dye uptake and fixation on the nanoparticle layer, driving the coloration toward its maximum intensity. The result is a fabric whose color is not a superficial paint job but a chemically anchored dye-protein system integrated into the fiber assembly.

Color alone, however, would not survive the environments the researchers had in mind. Spacecraft exteriors and astronaut textiles face vacuum, intense ultraviolet bombardment, and temperature swings that would destroy most conventional dye systems. To protect the coloration, the team applied a polydimethylsiloxane coating and cured it at high temperature. Polydimethylsiloxane, usually abbreviated PDMS, is a silicone elastomer renowned for its thermal stability, chemical inertness, optical clarity, and low surface energy. Cured as a thin film over the dyed fabric, it acts as a transparent shield: light passes through to reveal the vivid color beneath, while the polymer blocks moisture, moderates ultraviolet exposure, and cushions the underlying layers against mechanical and thermal stress.

The hydrophobic character imparted by the PDMS layer is one of the study’s most practically significant outcomes. After surface functionalization, the water contact angle of the samples reached approximately 120 degrees, a value well into the hydrophobic regime. Water beads on the surface rather than spreading, which limits moisture absorption, reduces contamination, and helps the fabric shed liquids in humid or wet conditions. For aerospace applications, where condensation, coolant leaks, or exposure to precipitation can compromise materials, this self-shedding quality adds a layer of robustness that goes hand in hand with the color protection. The combination of hydrophobicity and dye durability in a single treatment is what elevates the work from a coloration study to a genuine multifunctional materials advance.

The most striking evidence for the system’s resilience came from extreme environmental testing. The researchers subjected the PDMS-coated, dyed basalt fabric with silk fibroin nanoparticles to repeated cycles between 150 degrees Celsius and minus 196 degrees Celsius, the latter being the boiling point of liquid nitrogen. Such cycling imposes enormous thermal stress, because the components of a composite expand and contract at different rates, and brittle coatings tend to crack or delaminate under repeated shock. The PDBS fabric retained both its vivid coloration and its structural integrity through these cycles. It also withstood intense ultraviolet irradiation, the kind of exposure that in low Earth orbit bleaches and degrades most organic colorants within a short time. The team attributes this durability to the synergy of the three-layer architecture: the protein nanoparticles anchor the dye, and the silicone overlayer protects the whole assembly.

The authors point to a range of potential aerospace applications for the material. Deep-space exploration missions require components and surfaces that can be visually identified and distinguished, whether for assembly, inspection, or scientific marking, and a fabric that stays colorful under radiation and thermal cycling could serve as identification material on spacecraft. Protective textiles for astronauts could benefit from the same combination of visual function and environmental resistance, and flexible spacecraft coverings, such as thermal blankets or deployable structures, could incorporate the colored basalt fabric where both durability and visibility matter. Beyond aerospace, the researchers suggest the strategy could extend to other high-technology sectors where extreme conditions rule out conventional coloration methods.

The work also carries a broader lesson about bioinspired materials design. Rather than treating basalt fiber’s inertness as a flaw to be overcome with harsh chemical treatments, the team layered natural protein chemistry on top of the mineral surface, borrowing the dye-binding behavior that silkworm silk offers naturally, and then finished the assembly with a synthetic polymer chosen for its own extreme-environment credentials. The hierarchical structure, protein nanoparticles beneath dye beneath silicone, mirrors the way biological materials often combine soft and hard components at multiple scales to achieve properties no single layer could deliver. Funded by the National Natural Science Foundation of China and the Key Research and Development Program of Hubei Province, the study offers a template that other researchers may adapt to other inert reinforcements, other biopolymer intermediates, and other protective overlayers, potentially widening the palette of materials available to engineers who design for the harshest environments imaginable.

Subject of Research: Bioinspired coloration and environmental protection of basalt fiber composites using silk fibroin nanoparticles and PDMS coatings

Article Title: Bioinspired hierarchical assembly of silk fibroin nanoparticles and PDMS on basalt fibers for vivid coloration and extreme environment resistance in aerospace composites

Article References: Gao, H., Liu, S., Lei, Z., Cao, G., Sheng, D., Xiao, X., Zhang, Q., Jin, W., Wang, Y., Pei, K., & Xu, W. (2026). Bioinspired hierarchical assembly of silk fibroin nanoparticles and PDMS on basalt fibers for vivid coloration and extreme environment resistance in aerospace composites. Advanced Composites and Hybrid Materials. https://doi.org/10.1007/s42114-026-02062-5

Image Credits: AI Generated

DOI: 10.1007/s42114-026-02062-5

Keywords: basalt fiber, silk fibroin, PDMS, aerospace composites, hydrophobicity, acid dyeing, nanoparticles, extreme environment resistance, ultraviolet radiation, thermal cycling, bioinspired materials, textile engineering

The study, led by Quéren Hapuque de Castro Novelli of the University of Campinas in São Paulo, together with colleagues from ImmunoCamp Science and Technology, the Adolfo Lutz Institute, and other Brazilian institutions, focused on a quantity known as the zeta potential. This is a measure of the electrical potential at the slipping plane surrounding a suspended particle, and it governs how particles interact with each other and with their chemical environment. When two surfaces carry like charges, they repel; when their charges are opposite, they attract. For parasite eggs, cysts, and oocysts suspended in fecal material, these electrostatic forces can determine whether the structures sediment to the bottom of a tube, float to the surface of a dense solution, bind to debris, or drift uselessly out of the operator’s field of view.

Standard diagnostic protocols for intestinal parasites—spontaneous sedimentation, centrifugal sedimentation using formalin with ether or ethyl acetate, and flotation techniques based on zinc sulfate, sodium chloride, or sucrose solutions—are designed around a single physical property: the density of the parasite structure. Yet the researchers point out that these methods largely ignore electrostatic forces and the inherent hydrophobicity of parasite surfaces, factors that can reduce recovery efficiency and contribute to the low-to-moderate sensitivity that plagues routine parasitology. The motivation for the new work was to quantify this neglected variable in structures taken directly, or in natura, from preserved fecal samples rather than from laboratory-cultured parasites under idealized conditions.

To obtain clean parasite material, the team screened samples submitted to the Ouro Verde Hospital Municipal Laboratory of Campinas, selecting those that tested positive with high infection intensity by the Kato-Katz method. The samples, preserved in 7.5 percent buffered formalin, were filtered through 400 and 200 micrometer meshes and then subjected to repeated cycles of dilution in deionized water and centrifugation at 490 times gravity for five minutes, a process repeated five times to strip away fecal debris and concentrate the parasite structures. Under a stereomicroscope, individual eggs and cysts were then captured with a 10 microliter micropipette and transferred to fresh tubes, a meticulous manual procedure repeated six times that ultimately yielded approximately 400 helminth eggs and more than 1,000 protozoan cysts completely free of contaminating fecal material.

Surface charge was then measured with a Malvern Zetasizer Nano ZS, an instrument that determines zeta potential from electrophoretic mobility. An electric field is applied across the sample cell, inducing charged particles to move at speeds proportional to their charge density. The instrument tracks this motion by analyzing Doppler shifts in laser light scattered by the moving particles: faster-moving particles produce larger frequency shifts, and from these shifts the electrophoretic mobility and the zeta potential are calculated. Each sample was analyzed in triplicate, and the instrument’s software classified every measurement as good quality, ruling out artifacts from bubbles, viscosity, or inadequate particle concentration.

The results were unambiguous. All three parasite species carried net negative surface charges, with values ranging across samples from −14.2 to −32.1 millivolts. Giardia duodenalis cysts proved the most strongly charged, averaging −28 millivolts, while Ascaris lumbricoides eggs averaged −21.9 millivolts and Taenia species eggs averaged −18.4 millivolts. Statistical comparison across species groups using ANOVA confirmed the significance of the measurements. Notably, this is the first study ever to report the surface charge of Ascaris lumbricoides and Taenia eggs, filling a long-standing gap in the physicochemical characterization of these globally important pathogens.

The findings align closely with earlier work on related organisms studied under controlled conditions. Previous research found that Cryptosporidium oocysts carry surface charges of around −38 to −40 millivolts and Giardia cysts around −17 to −35 millivolts, with charge becoming less negative as the surrounding medium grows more acidic. Studies of Ascaris suum eggs have shown that more than 70 percent of the egg surface is hydrophobic, a property explained by electron microscopy studies revealing the egg’s layered architecture: an outer proteinaceous membrane, a middle chitin layer, and an inner lipid layer. That layered composition likely underlies the negative charge and hydrophobic character observed in the present study as well.

The clinical significance of these numbers becomes clear when placed in the context of known diagnostic failures. The authors cite work on the formalin-ether concentration procedure showing that even when centrifugation force, time, solvents, and surfactants were systematically optimized, certain parasite species stubbornly resisted sedimentation—as though an invisible chemical force were acting against their movement through the suspension. The zeta potential measurements now provide a candidate explanation: repulsive electrostatic interactions between the negatively charged parasite surfaces and the surrounding medium or other negatively charged fecal particles can oppose the gravitational and density-driven forces on which sedimentation and flotation depend, keeping eggs and cysts suspended and out of the diagnostic sediment.

Understanding these surface properties also points toward solutions. One proposed alternative technique, dissolved air flotation, exploits surface charge directly by using carrier molecules adsorbed onto air bubbles to capture oppositely charged particles, which then rise to the surface for collection. Similar electrostatic logic underpins the successful use of paramagnetic microspheres to isolate Schistosoma mansoni eggs from feces and of immunomagnetic particles to capture Cryptosporidium oocysts. The authors suggest that ionic compounds capable of reducing the repulsive charges in fecal suspensions could replace some of the harsh and hazardous reagents currently used—saturated salt solutions that damage parasite morphology, and volatile solvents such as ether and ethyl acetate that pose risks to laboratory workers and the environment. Evidence from malaria research reinforces the principle: red blood cells infected with Plasmodium falciparum trophozoites exhibit a zeta potential of −14.6 millivolts, significantly lower than uninfected cells, promoting the cytoadherence that is central to the disease’s pathology.

Beyond improving today’s diagnostic protocols, the researchers argue that these first quantitative surface-charge data for Ascaris and Taenia eggs open the door to an entirely new generation of tools, including engineered nanoparticles designed to bind specifically to enteric pathogens based on their electrochemical signatures. In an era when intestinal parasites still disproportionately affect communities with poor sanitation, and when preventive chemotherapy faces the growing threat of anthelmintic resistance, even modest gains in diagnostic sensitivity could translate into meaningful public health benefits. By revealing the hidden electrostatic forces at play inside a routine stool specimen, this study gives laboratory scientists a physical parameter they have largely ignored for decades—and a concrete target for the diagnostic methods of the future.

The choice of formalin as a preservative deserves particular attention when interpreting these measurements. Buffered formalin has been the workhorse preservative of parasitology laboratories for generations because it fixes parasite morphology and halts decay without requiring refrigeration, making it practical in resource-limited settings where most infections occur. Yet fixatives can alter surface chemistry, cross-linking membrane proteins and changing the ionizable groups exposed at the particle surface. The fact that robust negative charges persisted even after formalin fixation suggests that the electrostatic character of these structures is stable and intrinsic, but it also means that measurements from fresh, unfixed specimens remain an open question for future work.

The zeta potential itself is not a direct reading of the membrane charge but an indirect inference made at the slipping plane, the boundary between the tightly bound ion layer around a particle and the diffuse layer that moves with it under an electric field. This is why factors such as ionic strength, pH, and temperature of the suspending medium all influence the measured value. The deionized water and dilute formalin used here create a low-conductivity environment that favors clean electrophoretic measurements, but real fecal suspensions are far more chemically complex, rich in bile salts, fatty acids, and electrolytes that can screen or modify surface charges. Translating these clean measurements to the messy reality of a diagnostic suspension is the next conceptual step.

The public health stakes are considerable. Soil-transmitted helminths such as Ascaris lumbricoides infect hundreds of millions of people worldwide, and Giardia duodenalis is among the most frequently identified causes of diarrheal illness in children in low-income regions. World Health Organization deworming programs depend on diagnostic stool examination both to map infection prevalence and to monitor the impact of mass drug administration, yet the modest sensitivity of conventional concentration techniques means true infection burdens are likely underestimated, particularly for light infections that fall below the detection threshold of a single slide.

There is also a methodological legacy worth noting: the sedimentation and flotation techniques in routine use today descend largely from methods formalized in the early twentieth century, refined empirically long before particle electrophoresis became accessible to parasitology laboratories. The present study exemplifies a broader trend of importing characterization tools from colloid science and environmental engineering into medical parasitology, a convergence that previously proved fruitful in water treatment research on Cryptosporidium and Giardia, where surface charge informed the design of filtration and coagulation processes for drinking water safety.

Subject of Research: Measurement of surface zeta potential charges of intestinal parasite eggs and cysts in preserved fecal samples and their impact on diagnostic separation techniques

Article Title: The Evaluation of Surface Charges of Ascaris Lumbricoides, Giardia Duodenalis, and Taenia spp., in Preserved Fecal Samples Processed in Natura

Article References: de Castro Novelli, Q. H., Soares, F. A., Margatho, V. S., Fernandes, E. P., Suzuki, C. T. N., Sabadini, E., dos Santos, B. M., de Melo, L. C. V., de Oliveira Baccin, A., Falcão, A. X., & Gomes, J. F. (2026). The Evaluation of Surface Charges of Ascaris Lumbricoides, Giardia Duodenalis, and Taenia spp., in Preserved Fecal Samples Processed in Natura. Acta Parasitologica, 71(5), Article 209. https://doi.org/10.1007/s11686-026-01367-1

Image Credits: AI Generated

DOI: 10.1007/s11686-026-01367-1

Keywords: Ascaris lumbricoides, Giardia duodenalis, Taenia, zeta potential, surface charge, parasite diagnosis, fecal samples, sedimentation, flotation, electrophoretic mobility, hydrophobicity, parasitology

PVDF is a semicrystalline fluoropolymer prized for its chemical resistance, thermal robustness, mechanical durability, and innate hydrophobicity. It is also polymorphic, crystallizing in phases that include the nonpolar alpha form and the piezoelectric beta phase, a combination that makes it attractive for filtration membranes, sensors, energy harvesters, and water-oil separation systems. The Brazilian group, led by Gabriel da Cruz Dias of the Universidade Estadual de Maringá together with colleagues at UNESP and UNIFUNEC, asked a question that most prior studies had avoided: what happens when clay content climbs far beyond the low loadings, typically at or below 10 percent by weight, that researchers usually dare to use?

The answer required an unconventional fabrication route. Electrospinning, the dominant method for producing polymer nanofibers, relies on high electric fields, delivers modest production rates, and is difficult to scale. Solution Blow Spinning instead uses a pressurized gas jet to draw fibers from a polymer solution, offering higher throughput, simpler equipment, and lower cost. In the experiments, PVDF was dissolved in N,N-dimethylformamide at a concentration of 30 percent weight per volume, and montmorillonite K10 clay was dispersed in the solvent beforehand at levels of 3, 5, 10, 20, and 30 percent relative to the polymer mass. The mixture was fed through the nozzle at 76 microliters per minute under an air pressure of 140 kilopascals, with a working distance of 21 centimeters, yielding self-supported fibrous mats whose average fiber diameters stayed below 200 nanometers.

Scanning electron microscopy revealed that pure PVDF fibers were uniform, smooth, and cylindrical, with only occasional bead defects caused by jet instability and incomplete solvent evaporation. As clay content rose, imperfections multiplied. At 30 percent loading, clay clusters became prominent, hanging from the fibers like stones tied to a string and, according to the authors’ vivid analogy, pulling the loaded jets toward the collector faster than the polymer threads could follow. The consequence was measurable: with a constant 5 milliliters of solution for every production run, composite thickness fell only slightly up to 10 percent clay but dropped considerably at 20 and 30 percent, signaling that the process was losing efficiency as aggregates sabotaged fiber deposition.

Perhaps counterintuitively, the viscosity of the spinning solutions decreased as more clay was added. The explanation lies in sample preparation: because the clay was first dispersed in DMF, higher clay concentrations demanded additional solvent, and this dilution effect outweighed the thickening expected from suspended solid particles. Thinner solutions allowed polymer chains to disentangle and stretch more easily under the constant air pressure, producing finer fibers at high clay contents. Up to 10 percent clay, where solvent content remained constant, the trend reversed, with diameters rising slightly as viscosity increased—behavior consistent with earlier electrospinning and blow-spinning studies of clay-laden polymer solutions.

Elemental mapping by energy-dispersive X-ray spectroscopy confirmed that silicon, oxygen, and aluminum from the clay were distributed fairly homogeneously through the fibrous networks, with localized clustering at the two highest loadings. X-ray diffraction showed that both the alpha and beta crystalline phases of PVDF coexisted in every mat and, crucially, that clay addition did not alter this balance. The researchers attribute the phase formation to the blow-spinning process itself, in which rapid solvent evaporation favors the alpha phase while simultaneous fiber stretching promotes the beta phase, and they note that room-temperature processing may explain why clay did not act as the beta-phase nucleation catalyst reported in studies using heated routes. Differential scanning calorimetry reinforced the structural picture, showing a single melting peak near 176 degrees Celsius for all compositions, with a shoulder attributed to melting of the interfacial region between crystalline and amorphous lamellae.

Thermogravimetric analysis, however, delivered a caution. Pure PVDF remained stable to roughly 420 degrees Celsius before losing about 75 percent of its mass through dehydrofluorination, the reaction that releases hydrogen fluoride and leaves behind unsaturated carbon species. The composites degraded in two steps, and an initial degradation peak intensified with clay content, evidence that dispersed rather than exfoliated clay particles, and particularly the metal ions within them, catalyzed chain scission. Without the barrier effect that well-exfoliated clay layers would provide, higher filler contents reduced the composite’s thermal stability rather than enhancing it.

Mechanical testing traced a clear arc from reinforcement to collapse. Pure PVDF membranes were highly ductile, stretching about 58 percent before breaking with an elastic modulus near 13 megapascals, behavior typical of fibrous mats in which fibers align and reorient under load. Adding up to 5 percent clay increased both stiffness and tensile strength, because rigid particles acted as bridging points that transferred stress between neighboring fibers. Beyond roughly 5 to 10 percent, however, performance deteriorated sharply: elongation at break fell steadily with filler content, and at 30 percent clay the tensile strength had dropped by about 54 percent relative to pure PVDF. The culprit, visible in both electron micrographs and elemental maps, was agglomeration—defects that concentrate stress and sever efficient load transfer through the network.

Wettability measurements added an unexpected twist. All composites remained hydrophobic, with static water contact angles of 114 degrees for pure PVDF and, apart from a slight dip at 3 percent clay, rising values of 115, 119, 122, and 123 degrees as clay content climbed to 5, 10, 20, and 30 percent. Because montmorillonite is inherently hydrophilic, the trend runs against intuition, but the authors attribute it to increased surface roughness imparted by clay particles, which amplifies the low surface energy conferred by PVDF’s strongly bonded carbon-fluorine groups. A water-ethanol mixture reduced the contact angles, offering a simple lever for tuning wettability in applications such as filtration and separation without changing the material’s composition.

The study’s broader message is twofold. First, Solution Blow Spinning is a genuinely viable and scalable route to PVDF-based fibrous nanocomposites, producing sub-200-nanometer fibers at productivity levels electrospinning cannot match—here, 5 milliliters of a 30 percent solution yielded mats roughly 500 micrometers thick. Second, the technique’s tolerance for inorganic fillers has hard limits. The 30 percent formulation, with its thin, fragile mats, abundant aggregates, and depressed mechanical performance, marks a boundary that future work should not cross without improved dispersion strategies. For now, the sweet spot sits at low clay contents, where composites combine hydrophobic surfaces, controllable porosity, and enhanced stiffness, positioning them for filtration, environmental remediation, and membrane applications. The authors suggest that next steps should focus on refining filler dispersion, optimizing processing parameters, and evaluating functional metrics such as permeability, selective adsorption, and long-term stability under realistic operating conditions.

Beyond the specific findings, the study offers a useful methodological template for anyone probing the limits of high-throughput fiber fabrication. Rather than presenting a single optimized formulation, the authors deliberately swept a wide compositional range and documented where each characterization technique registered a change in behavior. This threshold-mapping approach—tracking solution viscosity, fiber diameter, mat thickness, crystalline phase content, degradation onset, tensile response, and contact angle as a function of filler loading—makes the results directly comparable across laboratories and provides benchmarks against which future dispersion strategies can be judged.

The work also situates itself within a broader shift in fibrous membrane research. Electrospinning remains the reference technique for producing submicron polymer fibers, but its dependence on high voltages and modest throughput has long constrained industrial adoption. Solution Blow Spinning, by contrast, requires only a pressurized gas supply, a syringe pump, and a rotating collector, all of which are inexpensive and straightforward to operate. The demonstration that this setup can accommodate inorganic loadings up to 30 percent by weight—while still yielding self-supported mats with sub-200-nanometer fibers—suggests that the technique’s real bottleneck is not fiber formation itself but the rheology and homogeneity of the precursor solutions.

For applications, the combination of hydrophobic surfaces, interconnected porosity, and tunable stiffness is particularly relevant to membrane-based separations, where water-repellent fibrous mats are sought for treatments involving oily wastewater or for supporting catalytic and adsorptive phases. The observation that a simple water-ethanol test liquid lowers contact angles hints at how wetting behavior could be tuned in practice, either through liquid choice or through post-processing that modifies surface texture. The authors’ open-access publication, released in the first volume of the Journal of Materials Science: Polymers, makes the full dataset available to groups working on scalable nanocomposite fibers, and the identification of agglomeration as the dominant failure mode above roughly 10 percent clay gives a clear target for subsequent studies employing surface-modified or organophilic clays, alternative solvents, or in-line dispersion methods.

Subject of Research: Fabrication of hydrophobic PVDF/clay fibrous nanocomposites via solution blow spinning with tunable mechanical properties

Article Title: Hydrophobic PVDF/clay fibrous nanocomposites prepared by solution blow spinning with tunable mechanical properties

Article References: Dias, G. D. C., Zadorosny, L., Sanches, A. O., de Paula, F. R., dos Santos, M. C., & Malmonge, L. F. (2026). Hydrophobic PVDF/clay fibrous nanocomposites prepared by solution blow spinning with tunable mechanical properties. Journal of Materials Science: Polymers, 1(1), Article 19. https://doi.org/10.1007/s44493-026-00018-1

Image Credits: AI Generated

DOI: 10.1007/s44493-026-00018-1

Keywords: PVDF, montmorillonite clay, solution blow spinning, nanocomposites, nanofibers, hydrophobicity, contact angle, tensile properties, thermal stability, crystalline phases, fibrous membranes, morphology