Stretchable, self-healing, transient macromolecular elastomeric gel for wearable electronics

Abstract

Flexible and stretchable electronics are emerging in mainstream technologies and represent promising directions for future lifestyles. Multifunctional stretchable materials with a self-healing ability to resist mechanical damage are highly desirable but remain challenging to create. Here, we report a stretchable macromolecular elastomeric gel with the unique abilities of not only self-healing but also transient properties at room temperature. By inserting small molecule glycerol into hydroxyethylcellulose (HEC), forming a glycerol/hydroxyethylcellulose (GHEC) macromolecular elastomeric gel, dynamic hydrogen bonds occur between the HEC chain and the guest small glycerol molecules, which endows the GHEC with an excellent stretchability (304%) and a self-healing ability under ambient conditions. Additionally, the GHEC elastomeric gel is completely water-soluble, and its degradation rate can be tuned by adjusting the HEC molecular weight and the ratio of the HEC to glycerol. We demonstrate several flexible and stretchable electronics devices, such as self-healing conductors, transient transistors, and electronic skins for robots based on the GHEC elastomeric gel to illustrate its multiple functions.

A Thermosetting Polyurethane with Excellent Self‐Healing Properties and Stability for Metal Surface Coating

“…[ 14–16 ] For example thiol‐disulfide exchange reactions(disulfide metathesis), [ 17,18 ] Diels‐Alder reactions, [ 19 ] or Boron‐oxygen bonding. [ 20 ] It has a nondynamic covalent bond, for example, hydrogen bonding, [ 21–24 ] metal–ligand coordination. [ 25,26 ] Judit et al.…”

Interface Design for Stretchable Electronic Devices

“…Nano-and microscale organic-organic interfaces for obtaining stretchability have been studied in the following areas; control of the permanent or dynamic bonds between two molecules in a homogeneously mixed state, [58][59][60] control of the dynamic bonding in the functional nanodomains where microphase separation is present, [63,64] adjusting the dynamic interaction between the functional nanodomains and the matrix, [67][68][69][70][71] creating strong interface between the organic matrix and the nanofibrils which is advantageous for securing stretchability due to its long contour path, [62,[73][74][75][76][77][78] and adjusting the interaction between infinitely long organic nanofibers and the organic matrix. [82][83][84] This section introduces some outstanding works for the different interfacial aspects.…”

“…Hao et al inserted low-molecular-weight glycerol in hydroxyethylcellulose to create hydrogen bonds between the polymer chains, and they formed a macromolecular gel with a high stretchability ( ≈ 300%) and the self-healing performance. [59] Kang et al reported a supramolecular polymer film constructed with a network of crosslinked polymer chains having both strong and weak hydrogen bonding units. [60] The strong hydrogen bonding units formed elastic nanodomains, and the weak bonding units dissipated the energy through the breakage of the bonds.…”

“…The molecules, nanostructures, microstructures, multiple layers, and unit devices forming the interfaces in stretchable devices have different modulus and mechanical hysteresis, therefore the interfaces need to be systematically studied according to the proper physical scales. The organic-organic composites with the nanoand microscale interfaces have focused on stretchability and selfhealing, [58,59,63] without considering integration with other constituent elements. In order for the organic materials to be used in practical unit devices or in integrated device arrays, the process stability (high-temperature processing, film uniformity, material compatibility to other units, etc.)…”

Intrinsically Stretchable and Self‐Healing Electroconductive Composites Based on Supramolecular Organic Polymer Embedded with Copper Microparticles

“…[ 20,21 ] On the other hand, for the development of advanced technologies like human–machine interfaces, the creation of new electronic devices and components having human‐like multifunctional properties is more critical. In general, the combination of electroconducting, stretching, and self‐healing abilities is a promising direction to meet the criteria for developing advanced technologies and applications, including soft robotics, [ 22,23 ] wearable healthcare electronics, [ 24–29 ] electronic/artificial skin and skin‐like electronics, [ 30–38 ] energy harvesting, and energy storage devices. [ 39–43 ]…”