Journal Article

IMPULSE-2025-00075

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Impact of Humidity on Water Dynamics and Electrical Conductivity in PEDOT:PSS/Cellulose Nanofibril Nanocomposite Films: Insights from Quasi-Elastic Neutron Scattering

Kreuzer, L. P. (Corresponding author)MLZ*TUM* ; Betker, M.Extern* ; Wolf, M.MLZ*TUM* ; Niebuur, B.-J. ; Ollivier, J.Extern* ; Söderberg, L. D. ; Roth, S. V.Extern*

2025
Soc. Washington, DC

Please use a persistent id in citations: doi:10.1021/acs.macromol.4c02412

Abstract: The water dynamics in a nanocomposite film thatconsists of the electrically conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and cellulosenanofibrils (CNFs) have been investigated during three cyclesof exposure to low and high relative humidity (RH = 5% and 85%,respectively) using quasi-elastic neutron scattering (QENS). Theobtained dynamical structure factors are transformed into theimaginary part of the dynamic susceptibility to better differentiatebetween the individual relaxation processes. In a humid environment,two different water species are present inside the films: fastmovingbulk water and slow-moving hydration water. During thefirst cycle, a large amount of hydration water enhances the polymerchain mobility, eventually leading to irreversible structural rearrangements within the film. In the subsequent cycles, we observed arelease of all bulk water and portions of hydration water upon drying, along with an uptake of both water species in a humidenvironment. The relaxation times of hydration water diffusion as a function of momentum transfer can be described by a jumpdiffusionmodel. The obtained jump lengths, residence times, and diffusion coefficients of hydration water suggest a change in thehydration layer upon drying: water molecules around hydrophobic groups are released from the film, while the hydrogen bondsbetween water and hydrophilic groups are sufficiently strong to keep these molecules inside the films, even in a dry state. The QENSresults can be correlated to the structural and conductive properties. In the dry state, the low hydration water content and theabsence of bulk water allow for improved wetting of the CNFs by PEDOT:PSS, which eventually increases the electrical conductivityof the films.

Keyword(s): Polymers, Soft Nano Particles and Proteins (1st) ; Soft Condensed Matter (2nd)

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Contributing Institute(s):

1. TOFTOF (TOFTOF)

Experiment(s):

1. Measurement at external facility

Appears in the scientific report 2025

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Database coverage:
; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 5 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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