A Novel Phosphoric Acid Crosslinked Copolymer as an Anhydrous Proton Conductive Electrolyte Matrix
Journal of Applied Polymer Science, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Publication Date: 2026
- Doi Number: 10.1002/app.71156
- Journal Name: Journal of Applied Polymer Science
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, Applied Science & Technology Source, Chemical Abstracts Core, Chimica, Compendex, INSPEC, Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Keywords: copolymer, dielectric parameters, N-[tris(hydroxymethyl)methyl]acrylamide, orthophosphoric acid, proton conductivity
- Karadeniz Technical University Affiliated: Yes
Abstract
A novel crosslinked copolymer electrolyte, poly(N-[tris(hydroxymethyl)methyl]acrylamide-co-styrene) [pP(TrisNHMAm-S)] was synthesized for the first time via free radical polymerization followed by orthophosphoric acid-mediated chemical crosslinking. The structural, thermal, and morphological characteristics were confirmed by FT-IR spectroscopy, TGA, and SEM analysis. Proton conductivity and dielectric properties were systematically investigated under completely anhydrous conditions (0% relative humidity) over a wide temperature (300–400 K) and frequency (20 Hz–1 MHz) range. AC conductivity (σ) measurements showed strong temperature- and frequency-dependent behavior. The membrane with higher phosphoric acid content exhibited nearly frequency-independent conductivity at room temperature (~4.5 × 10−4 S/cm) and reached values up to ~1.4 × 10−3 S/cm at 400 K. DC conductivity (σdc) analysis revealed thermally activated transport with two distinct regimes, yielding activation energies of approximately 0.056 eV at low temperatures and 0.29 eV (≈27.6 kJ/mol) at high temperatures. Dielectric spectroscopy demonstrated extremely high dielectric permittivity at low frequencies (ε′ ≈ 2.9 × 106 at 20 Hz and 300 K), attributed to enhanced interfacial polarization and proton density. Loss tangent (tanδ) analysis showed relaxation behavior and higher temperatures caused shorter relaxation times consistent with faster proton movement. pP(TrisNHMAm-S)-2 represents a novel promising solid polymer electrolyte (SPE) matrix with high proton conductivity and dielectric characteristics for future proton-conducting SPE applications.