Strain‐Invariant, Highly Water Stable All‐Organic Soft Conductors Based on Ultralight Multi‐Layered Foam‐Like Framework Structures

Abstract

Soft and flexible conductors are essential for the development of soft robots, wearable electronics, electronic tissue, and implants. However, conventional soft conductors are inherently characterized by a large change in conductance upon mechanical deformation or under alternating environmental conditions, e.g., humidity, drastically limiting their application potential. This work demonstrates a novel concept for the development of strain‐invariant, highly elastic and highly water stable all‐organic soft conductors, overcoming the limitations of previous strain‐invariant soft conductors. For the first time, thin film deposition technologies are combined in a three‐dimensional fashion, resulting in micro‐ and nano‐engineered, multi‐layered (<50 nm), ultra‐lightweight (< 15 mg cm−3) foam‐like framework structures based on Poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) and Polytetrafluoroethylene (PTFE), characterized by a highly strain‐invariant conductivity (≈184 S/m) between 80% compressive and 25% tensile strain. Both the initial electrical and mechanical properties are retained during long‐term cycling, even after 2000 cycles at 50% compression. Furthermore, the PTFE thin film renders the framework structure highly hydrophobic, resulting in stable electrical properties, even when immersed in water for a month. Such innovative multi‐scaled and multi‐layered functional materials are of interest for a broad range of applications in soft electronics, energy storage and conversion, sensing, water and air purification, as well as biomedicine.

PFAS-free Superhydrophobic Surfaces using Femtosecond Laser Processing and Hot-Filament Chemical Vapor Deposition

“…Various techniques for the chemical vapor deposition of polymer thin films exist [36]. While parylene CVD polymerization is limited to para-xylylene-precursors [37,38] and plasma-enhanced CVD (PECVD) is limited in retaining monomer functionalities [39], initiated chemical vapor deposition (iCVD) represents a technique with extraordinarily large toolbox [40] of monomers, that retain full chemical functionality [41] and can be deposited conformally on the nanoscale [42][43][44]. Fluoropolymers/PFAS via iCVD were previously used by Lau et al [45] in combination with carbon nanotubes to create SHS.…”

Supramolecular metallic foams with ultrahigh specific strength and sustainable recyclability

“…Advanced structural materials with ultrahigh strength and lightweight are highly desirable for a wide variety of technological applications, including aerospace 1 , 2 , automotive 3 , 4 , and construction industries 5 , 6 . Constructing porous architectures is a proven approach to realize weight reduction but usually lead to the decrease of mechanical properties, making it difficult to meet structural material requirements 7 , 8 . To date, it is still a great challenge to achieve ultrahigh mechanical properties of lightweight porous materials.…”

Highly Conductive PEDOT:PSS Aerogels

“…Among them, poly (3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) aerogels have been extensively studied for their relatively high electrical conductivity, diverse functionality, and superior chemical and environmental stability. [8][9][10] PEDOT:PSS aerogels are usually fabricated from commercially available PEDOT:PSS dispersions via the introduction of crosslinking DOI: 10.1002/adfm.202315188 agents into the dispersion [11][12][13][14][15][16][17][18][19] or coating PEDOT:PSS on non-conductive polymer templates. [20,21] Both the extrinsic crosslinkers and polymer templates are unfavorable for the removal of PSS component and the rearrangement of PEDOT chains, limiting the enhancement of electrical conductivity of the resultant PEDOT:PSS aerogels (typically lower than 100 S m −1 ).…”