Synthesis And Properties Of Functionalized Silicone Materials Containing Imidazolium Cations

Polyionic liquids(PILs)are an interesting class of polymers where ionic liquids(IL)are included in repeating units of polymer chains.PILs combine the unique physical and chemical properties of IL(i.e.high ionic conductivity,low saturated vapor pressure,wide electrochemical window,adjustability,good thermal stability and chemical stability)with the inherent properties of polymers(i.e.excellent eversatile processability,good mechanical stability and ease of functionalization).PILs have broadened the performance and applications of IL.In recent years,PILs have attracted widespread attention in the fields of polymer chemistry and physics,catalysis,separation,analytical chemistry,materials science and other fields.Due to the special structure of Si-O bonds,silicone polymers have many unique properties compared to other polymer materials,such as weatherability,radiation resistance,biocompatibility,insulativity,and low glass transition temperature.They are widely used in military industry,electric industry,healthcare industry,construction and other fields.With the rise of smart materials,silicone materials are widely used in smart materials due to their biocompatibility,transparency,and flexibility.At the same time,ionic liquids with high conductivity,good stability and excellent adjustability make it a hot spot in the field of smart materials.We combined ionic liquids with silicone polymers to prepare a kind of material which have both excellent properties.In this paper,we studied the synthesis and properties of imidazolium-based silicone materials.The maincontents are as follows:1.The imidazolium-based silicone material was synthesized at room temperature through poly-Radziszewski reaction with 1,3-bis(3-aminopropyl)tetramethyl disiloxane(BAPTMS)as the main raw material and oxalic acid as the ion crosslinking agent.The results show that a novel kind of silicone material with good conductivity and excellent self-healing ability has been prepared.Due to the presence of free ions,the conductivity of the silicone material reaches 2.79×10-4 S/m.This is a great improvement of the imidazolium-based silicone material considering silicone polymers excellent insulation.Because of the good conductivity,the silicone material is sensitive to stretching and can be applied as a flexible sensor.Due to the dynamic supramolecular interaction of the ionic cross-linking site,the material exhibits a high healing efficiency,reaching 89%in 6 h.In addition,the imidazolium-based silicone material emits a yellow-green fluorescence under ultraviolet light.2.Firstly,the aminopropyl-terminated polydimethylsiloxane was reacted with isofordone diisocyanate to synthesize aminopropyl-terminated polysiloxane-polyurea.And then the hydrogen-bonded imidazolium-based silicone material was synthesized via the poly-Radziszewski reaction.The results show that the material displays good conductivity and increased hydrogen bond reduces their conductivity.At the same time,due to the increase of Si-O-Si content,the material exhibits obvious hydrophobicity.The material also emits a yellow-green fluorescence under ultraviolet light.3.Imidazolium-based polysiloxane was synthesized with BAPTMS via poly-Radziszewski reaction,followed by reacting with octamethylcyclotetrasiloxane.its self-assembly performance was studied.The experimental results showed that the Imidazolium-based polysiloxane aggregated into spherical vesicles when the solvent was xylene or petroleum ether.