Synthesis Of Healable,Antibacterial And Conductive Polyurethane Composites And The Study On Sensing Performance

Flexible electronic sensors with real-time response and sensing to external stimuli have gained rapid development in recent years for their application prospects in smart electronic skin,timely medical diagnosis and wearable human-machine interfacing.However,the preparation of flexible electronic sensors with high sensitivity,broad sensing range,fast response to achieve full-range human healthcare monitoring is still a substantial challenge.In addition,the flexible electronic sensors with single sensing function cannot meet the user’s usage needs and seriously hinders its practical application.Thus,it is highly urgent to develop multifunctional flexible electronic sensors with sensing,healable and antibacterial functions,can effectively improve the service life of the sensor and promote its practicality.This thesis aims to develop multifunctional flexible electronic sensors with excellent sensing performance,healable and antibacterial functions through the facile synthesis of functional polyer matrix material and the sensor microstructure design.1.The polyurethane elastomer matrix functionalized with polysiloxane,Cu（II）ions-coordinated dimethylglyoxime（DMG）,and urethane groups（PUPDU-Cu）is prepared by polycondensation reaction from bis（3-aminopropyl）-terminatedpoly（dimethylsiloxane）（NH₂-PDMS-NH₂,Mn=～3000）,ethylene carbonate（EC）,isophorone diisocyanate（IPDI）and dimethylglyoxime（DMG）with the addition of copper（II）ions in the presence of catalyst dibutyltin dilaurate.The material exhibited excellent mechanical properties（the tensile strength and tensile strain at 3.11 MPa and 386%,respectively）,rapid healing performance（the healing efficiency up to 94.5%）,recyclable performance,good biocompatibility and reliable antibacterial capability（the bactericidal efficacy of the material against E.coli and S.aureus at 95.5%and 92.0%,respectively）.The functional polyurethane material lays a foundation for the preparation of high-performance multifunctional flexible electronic sensors due to their healable,recyclable and antibacterial performance,and excellent mechanical property.2.Inspired by the highly sensitive human skin microstructure,a skin bionic multifunctional flexible electronic sensor with excellent sensing performance,healable and antibacterial functions,was prepared from the face-to-face assembly of the MXene nanosheets-coated microdome array-contained PUPDU-Cu polyurethane film（bionic protective layer/sensing layer）and the conductive interdigitated electrode-coated PUPDU-Cu polyurethane film（bionic signal transmission layer）.The as-assembled sensor exhibited ultrahigh sensitivity(S₁=1573.05 k Pa^-1),broad sensing range（up to 325 k Pa）,fast response/recovery time（4/7 ms）,good reproducibility,healable capability,good biocompatibility and antibacterial function,which could be long-term safely contacted with the human skin.3.High-performance flexible electronic sensor can achieve highly sensitive sensing and real-time response to realize full-range human healthcare monitoring of various physiological signals for reflecting human health status.The sensor could be exploited to detect subtle human activities（such as pronunciation,human pulse,etc.）and large-scale human activities（such as joint bending,gait recognition,etc.）,showing great potential in timely medical diagnosis and wearable human-machine interfacing.