Design And Preparation Of Multifunctional Microporous Polymer Nanospheres

In the field of smart polymers,developing novel advanced polymers with multiple responses is of much greater practical importance,and thus has been becoming a new research hotspot,since the external environments are much more complex and the demands of practical applications are multi-leveled and diversified.Furthermore,the stereotype images of smart polymers usually lie in “soft materials”,such as micelles,vesicles and hydrogels.This imperfection hinders the applications of smart polymers in many areas.For example,the common smart polymers lack hyper-cross-linked polymeric frameworks and cannot demonstrate high surface areas and permanent nanoporosities that persist in the dry state.Therefore,it will be a valuable yet challenging structure design for smart materials to incorporate a carefully orchestrated rigid hyper-cross-linked component into their conventional soft polymeric frameworks.Porous materials,have become a research hotspot for their very small pore size(< 2 nm)and extremely high surface area.Up to now,much important progress has been made in synthesis strategy,material morphology,structural and compositional control over polymeric framework,and tuning of microporous structure in the field of microporous polymer.However,the polymeric frameworks of most microporous polymers usually comprise a highly cross-linked aromatic network which is rigid,hydrophobic and non-responsive,thus restricting their potential use in many advanced applications.Therefore,there is an urgent for developing smart microporous polymers with inherently multifunctional characteristics.In this dissertation,a novel method was first proposed to design and prepare a new kind of microporous polymer materials with multiple functions,by using poly4-vinylbenzyl chloride(xPCMS)as a microporous polymer matrix with one-step or multi-step organic / polymeric modification.Consequently,a variety of functional components were grafted onto the surface of those microporous nanospheres.Microporous polymer nanospheres xPCMS with pore size 1.2 nm were prepared by soap-free emulsion polymerization and hypercrosslinking method using4-vinylbenzyl chloride(CMS)as monomer.Then functional microporous polymer nanospheres xPCMS-Cz with 9H-carbazole-carbodithioate groups at the surface were prepared through a simple one-step substitution reaction between benzyl chloride grafting site at xPCMS and 9H-carbazole-carbodithioate groups.The resulting functional polymers not only maintain a good microporous pore structure and a high surface area,but also demonstrate hydrophilicity environmental fluorescence response and rapid adsorption properties for nitroaromatic compounds in aqueous phase.Then,the organic / polymeric reaction modified precursor xPCMS-Cz-MAh was obtained by further modifying xPCMS-Cz.xPCMS-Cz-MAh has not only a RAFT reaction precursor structure,but also the acid anhydride groups which can react with the functional molecules with the amine structure.Based on this,we modified xPCMS-Cz-MAh by multi-step organic / polymeric reaction and successfully designed and prepared the intelligent microporous polymer nanospheres xPCMS-Cz-PDMAEMA-CEA with multiple functions and environmental fluorescence response property.The as obtained xPCMS-Cz-PDMAEMA-CEA and xPCMS-Cz,still retains a good microporous pore structure and considerable surface area(530 m2/g).By characterizing the performance of xPCMS-Cz-PDMAEMA-CEA,xPCMS-Cz-PDMAEMA-CEA was found to be responsive to the pH of environment by changing its own fluorescent color.Furthermore,x PCMS-Cz-PDMAEMA-CEA can be used to detect heavy metal ions(Hg2+)and the deficient / rich electron aromatic compounds in the water by quenching response behavior under the corresponding pH value.At the same time,due to excellent hydrophilicity of the surface of xPCMS-Cz-PDMAEMA-CEA,the adsorption of nitroaromatic compounds and heavy metal ions in the aqueous system is realized.To sum up,in this dissertation,the innovative design and preparation of the multi-functional intelligent microporous polymer nanomaterials with excellent adsorption performance had been successfully developed.Such a design will provide scientific guides to unify the advantages of microporous polymers and intelligent polymers,which will make a great step forward to the development of preparationscience theories and applications of porous polymers.