Preparation And Application Of Special-shaped Functional Microspheres By Multi-component Click Dispersion Polymerization

Polymer microspheres have the advantages of high specific surface area,controllable particle size,and easy functionalization;polymer microspheres are widely used in fluorescence detection,adsorption separation,biomedicine,catalysis,photoelectric and other fields.The click polymerization and dispersion system combination can prepare micron-scale monodisperse microspheres under mild and free of environmental oxygen.Some progress has been made in the preparation of monodisperse microspheres by click-disperse polymerization,but most of the microspheres obtained are relatively smooth particles.However,there are still some challenges in the preparation of rough particles with uniform size and adjustable surface morphology,such as raspberry-like particles,by simple synthesis strategy.The polymerization rates of mercaptoisocyanate and mercaptoene are different in click-polymerization,and two reactions in the same dispersion system will affect the nucleation and growth stages of the particles.Most of the previous studies on the preparation of microspheres by click polymerization focused on the reaction of mercapto-isocyanate or mercapto-ene.The third component was only added as a small amount of functional monomer few of the two reactions were combined to prepare microspheres.To prepare functional microspheres by clicking polymerization of mercapto-isocyanate-ene,the reaction process needs to be regulated.In addition,the current applications of functional microspheres derived from point-to-point polymerization are mainly focused on fluorescence detection and drug encapsulation,rarely used in the construction of structural colors and preparation of chiral molecular carriers.Superwettability surface can be easily obtained by in situ polymerization grafting on fabric surface and further hydrophilic/hydrophobic modification of microspheres,but there are few researches in this area.In this paper,thiol-isocyanate raspberry-like microspheres with adjustable size and morphology were prepared by one-step click dispersion polymerization,and the formation mechanism of their morphology was investigated.The mercapto-isocyanate-ene click reaction process was controlled by controlling monomer type,catalyst addition time and feeding mode,and monodisperse functional microspheres were prepared.The application of click functional microspheres in antibacterial,loading metal nanoparticles,preparation of structural colors and hydrophobic fabrics was further explored.The main research contents of this paper include:1.Click polymerization of mercapto-isocyanate to prepare raspberry-like functional microspheres and explore its application:Monodisperse raspberry-like microspheres were prepared by one-step click dispersion polymerization of pentaerythritol tetra-3-mercaptopropionate(PETMP)and isophorone diisocyanate(IPDI).The formation reasons of raspberry-like morphology and the influence of monomer concentration on the particle size and morphology of microspheres were investigated.Polydopamine(PDA)shells were coated on the surface of raspberry-like microspheres.Platinum(Pt)nanoparticles were reduced in situ on the surface of thiol functionalized raspberry-like particles and on the surface of PDA shell coated particles.2.Click-polymerization of mercapto-isocyanate-ene components to prepare functional microspheres and explore its application:Sulfhydryl group can react with isocyanate and electron-deficient olefin of acrylate under alkali-catalyzed environment at room temperature,but isocyanate and olefin do not react.Therefore,different e-deficient enes with different structures were selected to explore the universality of microspheres prepared by the two reactions.One-step and two-step reactions were adopted to control the reaction process,and functional polymer microspheres with adjustable size,morphology and glass transition temperature(Tg)were prepared.The structure colors of nanoparticles prepared by one-step method were successfully prepared.Click microspheres with sulfhydryl(-SH)/ isocyanate(-NCO)groups on the surface were prepared by non-isomolar functional group ratio injection.Monodisperse liquid crystal click microspheres were prepared by clicking polymerization of 1,4-bis [4-(6-acryloxy hexyl)benzoyl]-2-methylbenzene(C6M)and 4’-(6-(acryloxy)hexyl)biphenonitrile(CHA)with PETMP and IPDI as the third component.The optical chirality transition of liquid crystal tap microspheres was investigated,that is,the transition from achirality to chirality induced by chiral inducers,which provided a new idea for the preparation of chiral liquid crystal microspheres.3.Preparation of superhydrophobic fabric by click polymerization of surface in situ sulfhydryl isocyanate:Firstly,click polymerization of mercapto-isocyanate in situ was carried out on the surface of cotton cloth,and click polymer particles containing-NCO group were grafted onto the surface of cotton cloth by non-isomolar ratio injection.Further,the superhydrophobic surface was formed by the reaction of-NCO group with octanethiol on particle surface.The cotton cloth has selfcleaning ability and high oil-water separation ability,and the separation efficiency is above 97%.The hydrophobic materials were prepared by extending the surface modification method to nylon mesh and stainless steel mesh,which provided a simple and environmentally friendly new idea for hydrophobic and superhydrophobic surface structure.