Year: 2025
Type: article
Abstract: The mechanical mismatch between semiconductors and biological tissues can be a challenge for the development of conformal bioelectronics. Organic mixed ionic‐electronic conductors (OMIECs) such as conjugated polymers with oligoether side chains are promising materials due to their low stiffness, which may minimize adverse immune reactions and thus promote biocompatibility. However, significant volume changes during electrochemical cycling—driven by ion and water ingression and expulsion—can lead to drastic changes in stiffness, complicating device‐tissue mechanical matching across redox states. Here, the electromechanical response of a thienothiophene‐based conjugated polymer with triethylene glycol side chains is investigated. Electrochemical nanoindentation and atomic force microscopy reveal a modest and reversible increase in elastic modulus at room temperature from ≈70 to more than 120 MPa upon electrochemical oxidation. This unusual mechanical stability is attributed to a reversible increase in π‐stacking that compensates for swelling‐induced softening. These findings demonstrate that it is feasible to design OMIEC materials with stable mechanical properties across redox states, opening new possibilities for compliant and tissue‐matched bioelectronic interfaces that remain mechanically invariant during operation.
Source: Advanced Functional Materials
Language: English
Subfield: Polymers and Plastics
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $5,790
Funders: National Science Foundation, U.S. Department of Energy, Northwestern University, Stiftelsen för Miljöstrategisk Forskning, Linköpings Universitet, Knut och Alice Wallenbergs Stiftelse, Vetenskapsrådet, China Scholarship Council, Marcus och Amalia Wallenbergs minnesfond, Office of Science, Engineering and Physical Sciences Research Council, Office of Naval Research, Division of Materials Research, Basic Energy Sciences, SLAC National Accelerator Laboratory, HORIZON EUROPE European Research Council, National Science Foundation Graduate Research Fellowship Program
Awards: G1229526393, G1243123360, G1286251239, G1824702445, Graduate Research Fellowship Program (GRFP), G193668846, G2156986825, G2343375527, G2371548206, G2416599479, G262532246, G3013266843, G303061748, G3203750490, G3352712625, G3836483654, G4235786860, Northwestern University Materials Research Science and Engineering Center, G4473368111, G4546055442, G495301720, G498139845, Cell-membrane anchored conductive polymers, G5570207115, Bio-derived and Bio-inspired Advanced Materials for Sustainable Industries (VALUED), G6550344761, G7283024673, Electrical Modulation of Elastic Moduli, G7938408761, G8382000481, G8876996369, G911061179, G969889393
OpenAlex ID: W4415299624