Preparation And Characterization Of Flexible Sensing Electronic Skin Based On Supramolecular

Skin that is the interface between human and the environment plays a vital role in shaping our interactions with the world.It can not only sense external information from the external environment and transmit the information to the brain,but also has the ability to prevent destruction and heal itself.Electronic skin that has various applications in the field of artificial limbs and artificial intelligence designing can simulate or even replace natural skin by mimicking its mechanical properties and the ability to sense.In addition,electronic skin can also be used as portable medical apparatus and instruments to monitor human physiological activities and vital signs for its ability to detect mechanical,temperature and humidity signals.Non-covalent interactions have been equipped to the network of ordinary hydrogels to obtain the supramolecular hydrogels by optimizing their network structure.Supramolecular hydrogels retain the properties of ordinary hydrogels,such as biocompatibility and environmental friendliness.In addition,supramolecular hydrogels have often quite stretchable,even self-healable for the crosslinking interactions in networks of supramolecular hydrogels are generally reversible.Here we combine the area of the electronic skin with the area of the supramolecular hydrogels to fabricate electronic skin that is highly sensitive,self-healing,with ideal good interfacial bonding.We also explore the application of supramolecular hydrogels in flexible devices,including:Here we designed and synthesized a cross-linking agent 4-(6-(3-(6-methyl-4-oxo-1,4-dihydropyrimidin-2-yl)ureido)hexylcarbamoyloxy)ethyl acrylate(UPyHCEA).Hydrogels were prepared by polymerization of UPyHCEA and AAm in micelles that provide hydrophobic environment.We did a variety of tests on hydrogels.The test results indicate the hydrogels are pretty soft,stretchable,self-healable,even have interface bonding capability.To be specific,the elastic modulus of hydrogels with 9.1 mM UPyHCEA was about 1.49 kpa-1 and a stretch of more than 87.At the same time,the hydrogels showed excellent healing efficiency for the existence of both hydrogen bonding and hydrophobic interactions.After cut,the hydrogels repaired themselves quickly,the tensile properties of the hydrogels were restored to 94%of the original,and the electrical conductivity of the hydrogels recovered rapidly.Most importantly,the cross-linking agent UPyHCEA can improve the interface adhesion between PAAm hydrogel and skin surface,and the interface peel strength is 3.62 Jm-2.By combining this supramolecular hydrogel with graphene fibers,we successfully prepared a capacitive electronic skin that is flexible and self-healable.This electronic skin had highly sensitivity(211.86 kpa-1)and extremely low detection limit(0.98 Pa).It can also dynamically match the complex surface of the human skin and monitor physiological activities such as finger joints,apex beats and arterial pulses on the skin surface,as well as distinguish different syllables emitted by the vibration of the throat.