Preparation And Properties Of Organic/inorganic Hybrid Microcapsules With Controllable Structure

With the advent of the intelligent era,human demand for the service life of materials has increased sharply.Microcapsule is a sphere with core-shell structure.It has the advantages of protecting the original physicochemical properties of core materials and simple application methods.It is widely used in the fields of self-healing materials,phase change materials and self-lubricating materials.In particular,the self-healing microcapsule composite can realize the physical repair of crack by controlling the release of the core material in the microcapsule,which can significantly prolong the service life of the material.The durability of traditional microcapsules based on polymer materials is poor,which is prone to early shell rupture or core material failure,resulting in its low self-healing repair performance.In order to improve the structural stability and repair efficiency of self-healing microcapsules,self-healing microcapsules with high stability,high embedding efficiency and low porosity were constructed.Multicomponent isocyanate and liquid metal have been used as core materials,and the organic/inorganic multilayer film modified by alumina nano-layer was used as dense shell.And the feasibility of its application in anti-corrosion,electrode and other fields has been explored.The specific research contents are as follows:(1)The organic/inorganic hybrid shell microcapsules embedded with 4,4'-dicyclohexylmethane diisocyanate(HMDI)were prepared by combining atomic layer deposition(ALD)with the principle of in-situ polymerization and interfacial polymerization,which improved the mechanical and thermal properties of the microcapsules.A densely stacked alumina nano-layer was formed by atomic deposition technology,which gave the hybrid microcapsules high mechanical properties and high heat resistance.In terms of mechanical performance improvement,hybrid microcapsules still maintained a complete structure and show excellent structural stability at 90?and0.5 MPa;In terms of heat resistance,the initial weight loss temperature of hybrid microcapsules was 200?,in thermogravimetric analysis,which was higher than that of the control group.Furthermore,the self-healing epoxy-microcapsule anti-corrosion coating was prepared on a carbon steel substrate and hot pressed.In the 48 h salt spray corrosion experiment,the carbon steel substrate at the damage of the hybrid microcapsule self-healing coating did not appear corrosion,while the carbon steel substrate at the damage of the control group appeared serious corrosion,which proved that the hybrid microcapsule greatly improved the self-healing and anti-corrosion performance of the coating in the harsh working environment.Therefore,the organic/inorganic hybrid microcapsules constructed by the modification of dense inorganic nano-shells have excellent durability,which could greatly improve the efficiency of self-healing microcapsules.(2)Based on the principle of in-situ polymerization and ultrasonic dispersion,polyurea formaldehyde microcapsules embedded with gallium indium alloy(EGa In)were prepared(EGa In-MS),which could improve the stability of EGa In in the environment and solve the problems of agglomeration,surface oxidation and dispersion of EGa In.Firstly,through the optimization of ultrasonic dispersion process,the morphology and particle size of EGa In-MS were controlled,and the particle size was about 20?m.Secondly,the self-healing electrode was prepared by mixing EGa In-MS with conductive silver paste electrode,and the self-healing piezoelectric sensor was prepared by combining with lactic acid-based piezoelectric elastomer film.The piezoelectric signal retention rate of the sensor was as high as 76.9%before and after cutting off the damage.Finally,a self-healing silicon anode was prepared with EGa In-MS as additive.It showed excellent cycle stability and rate performance,that is,after 100cycles of charge and discharge under the condition of current density of 2.1 A?g^-1,the specific discharge capacity and capacity retention of silicon negative electrode containing20%EGa In-MS were 806.7 m Ah·g^-1 and 35.15%respectively,which is significantly better than Pure Si and EGa In/Si;In addition,the silicon negative electrode of20%EGa In-MS showed excellent rate performance,and the average discharge specific capacity at 2.1 A?g^-1 and 4.2 A?g^-1 current density were 1400 mAh·g^-1 and 709 mAh·g^-1 respectively.