am8b08283_si_002.mpg (2.78 MB)
Stretchable, Transparent, Tough, Ultrathin, and Self-limiting Skin-like Substrate for Stretchable Electronics
media
posted on 2018-07-24, 00:00 authored by Adeela Hanif, Tran Quang Trung, Saqib Siddiqui, Phan Tan Toi, Nae-Eung LeeHuman 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.