In the relentless pursuit of advancing telecommunications technology, researchers are continually seeking materials capable of operating with extraordinary efficiency at increasingly higher frequencies. The dawn of 5G networks has already reshaped global communication landscapes, and the anticipation of 6G looms on the horizon, promising unparalleled data speeds and connectivity. Operating in the millimeter wave spectrum, these next-generation wireless systems demand components that manage electromagnetic signals with minimal interference, distortion, and energy loss. Central to this technological evolution are dielectric materials, insulating substances that guide electromagnetic waves. Achieving ultralow dielectric loss in polymers—materials prized for their flexibility and processability—has been a formidable challenge for scientists. Now, a breakthrough from a research team at Waseda University in Japan illuminates a promising pathway toward ultralow dielectric loss polymers, potentially revolutionizing high-frequency telecommunications.
Dielectric materials used in high-frequency environments must navigate a delicate balance: they require a low dielectric constant (D_k), which reduces signal delay and energy storage, and an exceptionally low dissipation factor (D_f), indicative of minimal energy loss as signals traverse the material. Polymers often exhibit favorable mechanical properties and design versatility, yet optimizing both D_k and D_f simultaneously has proven difficult. Past polymer architectures have either compromised on dielectric constant or allowed detrimental energy dissipation, hindering their practical application in the GHz frequency range essential for modern and future wireless communication.
The Waseda University team, led by Professor Kenichi Oyaizu of the Department of Applied Chemistry, embarked on an innovative approach inspired by prior work involving high refractive index polymers. Traditionally, poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) has been a benchmark polymer in balancing low dielectric constant and dissipation factor. However, Oyaizu and colleagues hypothesized that substituting oxygen atoms in the polymer backbone with sulfur—an element with distinct bonding characteristics—could drastically reduce dielectric loss. This bold strategy led them to develop derivatives of poly(phenylene sulfide) (PPS), including new copolymers with mixed oxygen and sulfur sequences, aiming to harness the advantages of both elements.
Central to their research was the synthesis of poly(2,6-dimethyl-1,4-phenylene sulfide) (PMPS), a PPS derivative where sulfur replaces the oxygen atoms found in PPO. This substitution capitalizes on the differing electrical properties of sulfur compared to oxygen. Sulfur, having larger atomic polarizability and a smaller bond dipole moment in the carbon–sulfur linkage, can potentially minimize dielectric loss, which is a critical advancement for materials operating at gigahertz frequencies. By experimentally measuring the dielectric properties of PMPS at 10 GHz, 40 GHz, and 80 GHz, the team directly compared its performance against PPO and newly synthesized copolymers with alternating sulfur and oxygen sequences, designated as P1 and P2.
The results were striking. PMPS demonstrated a dielectric constant of 2.80 with an ultralow dissipation factor of 0.00087 at 10 GHz—substantially outperforming PPO in minimizing energy loss. The copolymers further revealed nuanced trade-offs. Copolymer P1 exhibited a dielectric constant of 2.76 and a dissipation factor of 0.00169, while P2 showed a constant of 2.64 with a dissipation factor of 0.00130. These findings indicate that strategic incorporation of sulfur into the polymer backbone can systematically reduce dielectric losses, making sulfur a potent element for tuning electronic performance in polymer dielectrics.
Crucially, examination across the broad 10 GHz to 80 GHz frequency range revealed distinctive behaviors. While the dielectric constants of PPO, PMPS, and the copolymers remained relatively stable, the dissipation factor exhibited varying frequency dependence. Notably, P1 maintained an almost constant dissipation factor across this spectrum, showing the lowest dielectric loss at the highest frequency tested, 80 GHz. This remarkable frequency stability is attributed to the molecular architecture of P1, where alternating sulfur-oxygen units foster enhanced intermolecular forces that constrain molecular mobility, reducing the energy dissipated through molecular rotations and vibrations as electromagnetic waves pass through.
Professor Oyaizu elaborates on this phenomenon, noting that the alternating heteroatom design in P1 and P2 modifies intermolecular interactions, effectively elevating resistance to molecular motions that typically contribute to dielectric loss. Such molecular-level control ensures that P1 sustains its low dissipation factor even under the demanding conditions of ultra-high frequency signal transmission. Thermal stability, an essential characteristic for practical electromagnetic materials, was also preserved, highlighting the robustness of these novel polymers in real-world applications.
This work transcends mere material synthesis; it redefines the fundamentals of polymer dielectric design. By substituting oxygen with sulfur in key locations within the polymer chain, the team has unlocked a new dimension in dielectric engineering, paving the way for low-energy-loss materials that can meet, if not exceed, the rigorous performance needs of next-generation telecommunications infrastructure. This breakthrough holds promise not only for telecommunications but extends to other fields where high-frequency signal integrity is paramount, such as in radar systems, satellite communications, and advanced computing devices.
In light of these revelations, the implications of this research are vast and multifaceted. The efficient propagation of GHz electromagnetic waves through ultralow loss polymers could substantially improve the energy efficiency of 5G and future 6G systems. Devices fabricated with these materials may exhibit reduced heat generation and enhanced longevity, substantially advancing communication technology’s sustainability goals. Moreover, the tunable molecular design principles introduced can inspire the development of customized polymers tailored for specific frequency bands or application requirements, representing a versatile platform for future innovation.
The research team’s journey, documented in the prestigious journal Communications Materials, underscores the power of combining chemical ingenuity with rigorous experimental validation. With Professor Oyaizu and Junior Researcher Seigo Watanabe spearheading these efforts, the collaboration has illustrated how targeted heteroatom manipulation within polymers can yield dielectric properties that were previously unattainable. Their study, published on August 16, 2025, stands as a beacon for material scientists tasked with forging the backbone of advanced communication technologies.
As the world anticipates a hyper-connected future enabled by 6G and beyond, the materials underpinning these systems must evolve. The introduction of poly(phenylene sulfide) derivatives with ultralow dielectric loss and stable frequency responses represents a critical leap forward. These developments equip engineers and technologists with the tools necessary to sustain the ever-increasing demands on wireless communication—a pursuit essential for the digital age.
Professor Kenichi Oyaizu reflects on the broader impact of this discovery, emphasizing that the pioneering strategy of sulfur substitution opens a fresh avenue for the design of polymers with vastly improved dielectric characteristics. He envisions this as a foundational step towards realizing practical, scalable materials integral to pushing the boundaries of telecommunications far beyond current limitations.
The seamless integration of molecular chemistry, materials science, and telecommunications engineering embodied in this research epitomizes the interdisciplinary drive necessary to power tomorrow’s connectivity. As these novel poly(phenylene sulfide) derivatives transition from laboratory innovation towards commercial viability, their influence could ripple across industries, heralding a new era of efficient, high-frequency signal transmission.
Subject of Research: Not applicable
Article Title: Poly(phenylene sulfide) derivatives as ultralow dielectric loss materials with stable frequency response
News Publication Date: 16-Aug-2025
Web References:
https://doi.org/10.1038/s43246-025-00917-w
References:
Watanabe, S., Miura, S., Miura, T., Tsunekawa, Y., Ito, D., & Oyaizu, K. (2025). Poly(phenylene sulfide) derivatives as ultralow dielectric loss materials with stable frequency response. Communications Materials, DOI: 10.1038/s43246-025-00917-w
Image Credits: Kenichi Oyaizu from Waseda University, Japan
Keywords: Telecommunications, Internet, Electrical engineering, Software, Materials science, Engineering, Nanotechnology, Manufacturing, Polymers, Dielectrics
