Self-healing Polymeric Ionic Liquids Composite Materials Based On Multiple Reversible Interactions

High-strength materials have been widely used in load-bearing materials such as cartilage and tissue engineering scaffolds,electronic skin,and automotive industry.However,these materials are inevitably damaged in the practical usage such as stretch,bend,and compression,leading to the loss of original functions and shorten the lifetime.An effectively approach to solve this problem is to endow materials with self-healing capability.Polymeric Ionic Liquids(PILs)possess many advantages such as excellent ion conductivity,chemical stability,and non-flammable has been widely used in polymer chemistry,electrochemistry,material science and energy science.Combining the self-healing ability with the properties of PILs allows us to design various functionalized materials with specific properties and functions.Moreover,multiple reversible interactions are crucial to the control of the mechanical properties of the material.Therefore,in this thesis,,We prepared self-healing polymeric ionic liquids composite materials based on multiple reversible Interactions:(1)The salt-mediated polyampholytes(PA)hydrogels with high mechanical strength,excellent self-Healing property and satisfactory electrical conductivity are prepared by one-step polymerization of positively charged monomer containing urea modified ionic liquid(urea-IL)and negatively charged 3-sulfopropyl meth-acrylate potassium salt monomer(SPMA)and dialyzing in water.We control the salt content of the hydrogel by controlling the dialysis time to effectively regulate the strength of electrostatic interactions,thereby regulating the mechanical properties and self-healing properties of the PA hydrogel.Additionally,the incorporation of hydrogen-bonding interactions between urea groups into the hydrogels dramatically improves their toughness.After dialysis in water for 3 d,the hydrogel becomes mechanically robust with a high Tensilestrength of 1.3 MPa.Moreover,the hydrogel can automatically heal mechanical damage after 24 h at room temperature and the healing efficiency is~91%.The presence of salt also endows hydrogel with satisfactory conductivity.(2)The rapidly room-temperature self-healing polymeric ionic liquids materials based on Li~+-O coordination are fabricated by Poly-Radziszewski reaction and simple post-processing.The as-prepared polymeric ionic liquids materials show excellent mechanical properties with a strain at break up as high as 1100%.The reversibility of electrostatic interactions between the imidazolium cations and the counteranions(TFSI)and coordination interactions between lithium-ion and oxygen atom and the high mobility of polymer chains endow the materials with the ability of rapidly self-healing at room temperature.They can completely healed damages by cut at room temperature with 2 min.By simply adjusting the monomer ratio and the content of lithium-ion,we can accurately control the mechanical properties and self-healing ability of the material.