Stretchable, Transparent, Tough, Ultrathin, and Self-limiting Skin-like Substrate for Stretchable Electronics

Abstract

Human skin is highly stretchable at low strain but becomes self-limiting when deformed at large strain due to stiffening caused by alignment of a network of stiff collagen nanofibers inside the tissue beneath the epidermis. To imitate this mechanical behavior and the sensory function of human skin, we fabricated a skin-like substrate with highly stretchable, transparent, tough, ultrathin, mechanosensory, and self-limiting properties by incorporating piezoelectric crystalline poly((vinylidene fluoride)- co-trifluoroethylene) (P(VDF-TrFE)) nanofibers with a high modulus into the low modulus matrix of elastomeric poly(dimethylsiloxane). Randomly distributed P(VDF-TrFE) nanofibers in the elastomer matrix conferred a self-limiting property to the skin-like substrate so that it can easily stretch at low strain but swiftly counteract rupturing in response to stretching. The stretchability, toughness, and Young's modulus of the ultrathin (∼62 μm) skin-like substrate with high optical transparency could be tuned by controlling the loading of nanofibers. Moreover, the ultrathin skin-like substrate with a stretchable temperature sensor fabricated on it demonstrated the ability to accommodate bodily motion-induced strain in the sensor while maintaining its mechanosensory and thermosensory functionalities.

Mechanically and biologically skin-like elastomers for bio-integrated electronics

“…Fiber reinforced composites have been developed to mimic the mechanical properties of skin. The nanofibers increased the toughness of resultant composites, but also compromised the stretchability (below 150%) 25,26 . The lack of strong interaction between nanofibers and matrix may lead to stability issues when the elastic materials were subjected to cyclic deformation.…”

Highly Stretchable, Transparent, and Bio‐Friendly Strain Sensor Based on Self‐Recovery Ionic‐Covalent Hydrogels for Human Motion Monitoring

“…Figure 3c and Table S1, Supporting Information, display the comparison of our strain sensor with recently reported soft electronics in the field of transmittance and maximum strain. [37,[55][56][57][58][59][60][61][62][63][64] Obviously, our PAC hydrogel combines the advantages of both high transparency and large strain range.…”

Graphene Oxide as an Optical Biosensing Platform: A Progress Report

“…Later (2013-2014), Prof. Alberto Bianco, Prof. Peter Wick, and other members of the EU Graphene flagship project took action on this important matter and recommended a specific nomenclature and classification for 2D carbon materials, mainly based on their lateral size, number of layers, and oxidation degree. [8][9][10][11][12] Aside from this, monolayer GO optical transmittance has been reported to be modulated up to 24.8% by using an external electric field, [13] which has been associated with the electric-field-induced changes of electronic density of localized states and may enable new biosensing strategies based on electrochromic or optoelectronic principles/mechanisms. The following section summarizes and highlights these crucial features with especial emphasis on their overall impact related to optical bio/sensing performance.…”

“…Hence, this feature should be carefully evaluated in GO-based bio/sensors intended for visual determination, optoelectronic interfaces and wearable devices. [8][9][10][11][12] Aside from this, monolayer GO optical transmittance has been reported to be modulated up to 24.8% by using an external electric field, [13] which has been associated with the electric-field-induced changes of electronic density of localized states and may enable new biosensing strategies based on electrochromic or optoelectronic principles/mechanisms. [14] Moreover, GO thickness has been reported to be crucial in laser energy absorption capabilities and laser energy transfer for efficient laser desorption/ionization mass spectrometry analysis.…”