Fabrication Of Carbon-Polymer Two-Dimensional Composite Films And Their Application In E-Skin

Artificial E-skin could have profound implications for artificial intelligence（AI）,prosthetics and medicine as their ability to imitate skin’s unique characteristics in response to complex sensations,such as pressure,temperature and chemical stimulus.Recently,significant advances have been achieved in E-skin study.However,E-skins has not yet been widely applied in our daily life as there exist critical challenges for E-skin,such as stability,sensitivity,narrow sensing range,and anti-interference performance.Thus,to further develop and design new structural materials for the fabrication of high performance E-skin sensor is significantly important.Carbon nano materials,such as carbon nanotubes and graphene,have combined superiorities such as good electrical conductivity,intrinsic flexibility,ease of chemical functionalization,enabling them to be promising candidate materials for flexible and wearable E-skin electronics.However,it is a great challenge for carbon nano materials to maintain their high performance when they composed with soft polymers.Thus,it is of vital importance to develop and design new structure for carbon and polymer composite materials for applications in next-generation high performance soft electronic.In this thesis,the author has developed bioinspired carbon-polymer based heterogeneous sensing junction structure and asymmetric composite structure for E-skin.The main works are as follows.（1）.Inspired by the molecular detecting system based on weak bond interactions in the natural organism,we designed a new concept of tunable graphene-polymer heterogeneous nano sensing junction by confining reasonable thickness sensing material into graphene nanochannels.The promising advantages of the sensor allow us to record humidity fluctuation information in real time during a user’s speech and breath,which can both reveal the speech feature and monitor the respiration rate accurately.Importantly,this advanced sensor provides a new opportunity for accurate and reliable physiological and psychological monitoring by detecting the subtlest RH fluctuations on human skin in a non-contact way.（2）.A novel symmetric composite material design strategy is developed to fabricate soft pressure sensor exhibits unprecedented comprehensive properties with both high sensitivity(1875.53 kPa^-1)and wide linear detection range（0-40 kPa）.Taking advantages of these performances,a universal high accuracy wireless and wearable pulse monitoring system was built.This platform first provides the subtle arterial pulse signal information even under the interference of strong body movement in real-time,which could not have been realized before.（3）.A stretchable symmetric composite material based on wrinkled elastomer-graphene is fabricated.This work provides a candidate strategy for the fabrication of stretchable graphene-based E-skins.Based on this stretchable material and device design,a human-machine interaction system was constructed in this work.In summary,a highly sensitivity and fast response humidity sensor based on graphene-polydopamine nanoheterojunction materials was prepared by nanocomposite method.In addition,a highly sensitive and wide linear response piezoresistive flexible devices and a stretchable self-power E-skin were constructed by asymmetric compose of interfacial self-assembled graphene film with polymer elastomers.These two devices are expected to be applied in medical and human-computer interaction fields.