Investigation Of Ionogel Based Flexible Strain Sensor

Intelligent,flexible and wearable electronics have attracted increasing research interests in recent years.As an important part of wearable electronic products,flexible strain sensors have received extensive attention.However,the currently reported flexible strain sensors still have some problems,such as narrow working temperature range,inability to balance high stretchability with high sensitivity,large hysteresis,and poor self-adhesion.Therefore,there is an urgent requirement to develop high-performance flexible strain sensors to meet the growing demand for wearable electronics.Due to their unique properties,ionogels have been widely used in the field of electronics,but their application as flexible strain sensor is rarely reported.So,in this research,three novel ionogels were prepared,their performance as flexible strain sensors was studied,and the feasibility of ionogels as high performance strain sensors was explored.The main research contents are as follows:1.The weak mechanical properties of traditional ionogel greatly limit their application in the field of strain sensors.By introducing the hydroxyethyl acrylate(HEA)cross-linking network into the agarose cross-linking network,a physically cross-linked double-network ionogel(DN ionogel)was successfully obtained.Due to the unique energy dissipation mechanism,the double network structure greatly improved the mechanical property of the ionogel,its tensile strength could reach 0.37 MPa,and the strain could reach 700%.In addition,DN ionogel possessed high transparency and wide working temperature range.As strain sensor,DN ionogel exhibited remarkable electromechanical properties,such as good linear correlation,fast response speed,superior stretchability,low hysteresis and outstanding durability,and could monitor different human activities.2.How to endow the strain sensors with excellent repetitive self-adhesion is the hotspot and difficulty of the current research.Acrylic acid(AA)and 1-ethyl-3-methylimidazolium chloride([EMIM]Cl)were used as raw materials to synthesize polyacrylic(PAA)ionogel by in-situ photopolymerization.PAA ionogel exhibited excellent self-adhesion,and could repetitively adhere to different substrates.PAA ionogel possessed high transparency,superior stretchability,wide operating temperature range and good self-healing property.Since the Young's modulus of PAA ionogel is similar to human skin,it could be used as a high-performance electronic skin to detect human motions and temperature change.The manufacturing method of ionogel was simple and fast,so it is expected to achieve large-scale production.3.In order to improve the environmental stability of the ionogel,the hydrophobic monomer butyl acrylate(BA)and the hydrophobic ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonylimide)([BMIM]TFSI)were used as raw materials to fabricate polybutyl acrylate(PBA)ionogel by in-situ photopolymerization.PBA ionogel exhibited high transparency,high stretchability,wide operating temperature range and excellent environmental stability.PBA ionogel could repetitively adhere to different substrates firmly even under water.PBA ionogel could be applied as high performance strain-temperature sensor...