Research On Flexible Multi-sensory Electronic Skin Based On Silk Fibroin

Due to wide application prospects in artificial intelligence,health monitoring,virtual reality and other fields,flexible and stretchable multi-functional intelligent sensors have been widely concerned by scientific researchers.By transforming physical changes such as temperature and stress into electrical signals,it can sense the external world.In this paper,we focus on the research of a flexible bionic multi-functional sensor for human health assessment and plant growth monitoring.We hope that the sensor can sense the external temperature and micro deformation as human skin,and also can monitor the plant growth status.Because of ultra-light,ultra-thin and air permeability,the sensor will not affect not only the skin movement and sweat evaporation,but also the normal growth of plants,which will greatly expand its application range.Silk fibroin,as a natural material,possess excellent mechanical properties,biodegradability and biocompatibility.It is an ideal substrate for wearable flexible sensors.In this paper,the substrate of regenerated silk fibroin film was prepared by solution method,and then the content of ?-nano microcrystalline and the structure of?-nano microcrystalline mesoscopic network were controlled by mesoscopic doping to overcome the shortcomings of poor mechanical flexibility and chemical stability of silk fibroin,and the silk fibroin film with high flexibility,chemical stability and biocompatibility were developed.At the same time,electrospinning and magnetron sputtering were used to prepare conductive nanofibers with high aspect ratio.The effects of different spinning parameters on the morphology of polymer nanofibers and the distribution of metal nanoparticles were discussed.The conductive nanofibers were covered on the surface of the substrate by the wet transfer method,and the sandwich structure of silk fibroin/conductive Nanofibers/silk fibroin was constructed.The results show that the mesoscopic doped silk fibroin sensor has excellent mechanical flexibility,and the tensile ratio is up to 100%.The light transmittance of the device is more than 80%when the square resistance of 20 ?/sq nanowire is constructed.The strain coefficient is 3.93 and the temperature sensitivity coefficient is 0.137%°C-1 at room temperature,which showing excellent mechanical or thermal response characteristics.When testing mechanical flexibility,the resistance response and sensitivity did not change significantly after 7000 cycles of tensile changes.Through the experiments of water vapor permeability and macromolecule permeability,the water vapor permeability of the device is about 183.59 mg/h,and there is no allergy and swelling in the long-term application process of the device on the skin surface,and the biodegradation can be controlled within 24 h.Based on this,the flexible multi-sensory sensor prepared by the above method was used for real-time monitoring of human motion and health.The device can not only accurately monitor the small movement of human joints,but also real-time monitor the pulse beat frequency of human body,which can reflect the human health through comprehensive data analysis.In the shooting process,correct the shooting posture and muscle force of the athletes are reliable.In addition,the sensor was used to monitor the growth of plant leaves.The effect of external injury on the growth of Chlorophytum Phnom Penh leaves are studied in detail.The growth of different stages of Narcissus is tracked and the effect of light on the leaf state and flowering period of Narcissus is explored.These applications fully prove that the flexible multi-sensory sensor in this paper has broad application prospects in the field of human health assessment and plant growth monitoring.