Preparation Of Silk Fibroin Composite Hydrogel And Its Application In Flexible Sensors

In recent years,with the rapid development of flexible electronics and biomimetic fields,the new kind of hydrogel material has aroused great interests and wide concern of scholars.Hydrogel is widely used in flexible wearable sensors,electronic skins,implantable medical devices,and other fields due to its outstanding characteristics including softness,high stretch,and highly matching modulus with biological tissues.This thesis focuses on the preparation,morphology and structure characterization and performances of the silk fibroin composite hydrogel(SFH)including mechanical properties,self-adhesiveness,and self-healing properties,showing its application value in the fields of human motion detection,health monitoring,voice recognition,and other fields as a flexible wearable sensor.The main innovations and works of this thesis are as follows:1.A high-stretching,self-adhesive and self-healing silk fibroin(SF)composite ionic conductive hydrogel was prepared through a simple and low-cost one-pot thermal polymerization method.The hydrogel is chemically and physically cross-linked by acrylamide(AM),acrylic acid(AA)and SF.It has a double network structure and is stable in the air.The addition of SF not only greatly improves the mechanical properties of SFH,but also gives the hydrogel excellent self-adhesiveness and self-healing ability.It can form a tough combination with the surface of tested object such as the human skin without additional tapes.The fit improves the accuracy and stability of signals in the detection and transmission process of SFH flexible wearable sensors.In addition,SFH can realize the synchronous recovery of electrical and mechanical properties under room temperature without external stimulation such as light,heat,electricity,etc.The electrical properties of the SFH can recover instantaneously owing to ion conduction,and its mechanical self-healing efficiency can reach up to 50%after 12 hours healing at room temperature.2.Due to its wide pressure detection range(about 0.455～568.9 kPa),SFH can be used as a resistive-type strain/pressure sensor to monitor the joint movements and facial micro-expression of the human body in real time,and it has a sensitive response to temperature in the range of-10～60℃.SFH,which has a dual response to machinery and temperature,is expected to be applied in fields of flexible wearable sensors,electronic skin,human health monitoring and other fields.3.The SFH flexible sensor has excellent response sensitivity to tiny and complicated vibrations.It can sense the subtle movements of the neck skin during the human phonation and output information specified as resistance.It can be integrated with machine learning of artificial intelligence and applied in speech recognition,pronunciation rectification,"intelligent vocalization" of deaf-mutes,early detection of laryngeal diseases and other fields.