| Stretchable strain sensing materials are widely used in electronic skin,human health and human detection due to their excellent flexibility.Wearable devices and bioelectronics,which are usually in contact with the human body and living organisms and used for a long time,need to have excellent skin affinity,mechanical flexibility,and antibacterial properties.However,as more and more various commercial polymer films are used as substrates/substrates for constructing various electronic products,the accumulation pollution of electronic waste has been caused.At the same time,serious concerns have been raised about the environmental pollution caused by this ubiquitous e-waste.The degradability and single-use properties of materials are very important for the future sustainability of wearable devices and bioelectronics,which means that the flexibility and stretchability of materials are critical for devices on the skin,while achieving their degradation and recycling are also indispensable.In addition,antimicrobial properties are also important for skin-contact devices to meet long-term biosafety and environmental requirements.Therefore,it is still challenging to realize a multifunctional electronic platform with the above-mentioned advantages on one material.In this paper,a composite antibacterial material was prepared by electrospinning and spraying techniques,and its sensing properties were investigated.The main research contents are as follows.First,polyvinyl alcohol(PVA)was modified by amino-terminated hyperbranched polymer(HBP-NH2)(MPVA),and the electrospinning process of MPVA was explored.When the voltage is 15 kV,the spinning solution concentration is 120 mg ml-1,the flow rate is 0.1 ml h-1,and the receiving distance is 20 cm,the morphology of MPVA fibers is better.Compared with the pure PVA fibrous membrane(Elongation at break～83%,Breaking strength～10.2 MPa),the MPVA fibrous membrane exhibited higher elongation at break(～123%)and lower tensile stress(2.4 MPa).At the same time,the MPVA fiber membrane has good stretching cycle characteristics under 50%strain,which also meets the deformation needs of human skin.Then,silver nanoparticles(AgNPs)can be successfully introduced through the capture and reduction of silver ions by HBP-NH2,which can endow the flexible substrate materials with antibacterial properties.When the concentration of reduced silver nitrate is 4 mM,the MPVA/AgNPs fiber membrane has good flexibility and recovery,and meets the deformation range of human skin(～50%).Due to its good encapsulation effect on AgNPs,MPVA/AgNPs fiber membrane has a good inhibitory effect on Escherichia coli and Staphylococcus aureus,and the bacteriostatic rate can reach more than 99%.In addition,the fiber membrane can be easily dissolved in water and regenerated by electrospinning,which is environmentally friendly,and the regenerated MPVA/AgNPs fiber membrane still has good morphological characteristics and excellent antibacterial effect.Finally,nano silver wires(AgNWs)with excellent electrical conductivity were used to build a conductive network by spraying method and assemble the AgNWs/MPVA/AgNPs sensing material.It is found that when the AgNWs content is 111.1μg cm-2,this sensing material has good cyclic resistance response ability under different strain conditions,and the resistance response of the material in the tensile process is between the tensile strain and the tensile strain.A good linear relationship was established with a correlation coefficient(R2)as high as 0.995.In addition,when the AgNWs content is the same,pre-tension is applied to the fiber membrane during the spraying process.Due to the resilience of the fiber membrane,after the tension is removed,it is beneficial to form a more compact conductive network of AgNWs.The cyclic resistance response performance of the AgNWs/MPVA/AgNPs sensing material is more stable under different strain conditions,and the sensitivity is also improved.The sensing material can be used to monitor the bending-extending activities of human fingers and wrist joints through resistance changes,showing good bending repeatability... |
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