Facile Soaking Strategy Toward Simultaneously Enhanced Conductivity and Toughness of Self-Healing Composite Hydrogels Through Constructing Multiple Noncovalent Interactions

Abstract

Tough and stretchable conductive hydrogels are desirable for the emerging field of wearable and implanted electronics. Unfortunately, most existing conductive hydrogels have low mechanical strength. Current strategies to enhance mechanical properties include employing tough host gel matrices or introducing specific interaction between conductive polymer and host gel matrices. However, these strategies often involve additional complicated processes. Here, a simple yet effective soaking treatment is employed to concurrently enhance mechanical and conductive properties, both of which can be facilely tailored by controlling the soaking duration. The significant improvements are correlated with co-occurring mechanism of deswelling and multiple noncovalent interactions. The resulting optimal sample exhibits attractive combination of high water content (75 wt %), high tensile stress (∼2.5 MPa), large elongation (>600%), reasonable conductivity (∼25 mS/cm), and fast self-healing property with the aid of hot water. The potential application of gel as a strain sensor is demonstrated. The applicability of this method is not limited to conductive hydrogels alone but can also be extended to strengthen other functional hydrogels with weak mechanical properties.

Stretchable Conductive Polymers and Composites Based on PEDOT and PEDOT:PSS

“…This IPN allowed for high mechanical stability and strength while maintaining good conductivity. An interesting variant of the double network hydrogels involved the use a dynamic assembly process to enable healing . Wu et al reported the synthesis of a thermoplastic PEDOT:PSS IPN with a supramolecularly crosslinked polymer which healed at 90 °C ( Figure a).…”

Strategies for Designing Stretchable Strain Sensors and Conductors

“…In addition to mechanical properties, achieving high electrical conductivity is also challenging. There are mainly two types of conductive hydrogels, i.e., hydrogels consisting of intrinsically conductive materials such as metal nanowires, carbon nanomaterials, or conducting polymers (polypyrrole, polyaniline, and PEDOT:PSS) and ionic hydrogels prepared by adding polyelectrolytes or salts . To achieve high electrical conductivity, it is vital to effectively incorporate conductive materials in the matrices of polymeric hydrogels due to nanomaterials' tendency to agglomerate and the low solubility of the conducting polymers.…”

“…To achieve high electrical conductivity, it is vital to effectively incorporate conductive materials in the matrices of polymeric hydrogels due to nanomaterials' tendency to agglomerate and the low solubility of the conducting polymers. Wang et al reported a facile soaking strategy by soaking freezed/thawed PVA‐PEDOT hydrogels in sulfosuccinate acid aqueous solution to simultaneously improve their conductivity and toughness. Inspired by the method of using preconstructed 3D conductive networks to develop conductive polymer nanocomposites, Song et al demonstrated highly stretchable conductors by backfilling PNIPAM into Ag nanowire aerogel framework ( Figure ).…”

Properties of conductive polymer hydrogels and their application in sensors

“…prepared a poly(vinyl alcohol) (PVA)‐PEDOT‐based hydrogel with enhanced toughness and conductivity by soaking the synthesized hydrogel in sulfosuccinic acid (SA) aqueous solution [Fig. (a)] . The treated hydrogel can withstand tremendous deformation (stretching and twisting) [Fig.…”