Study On The Synthesis And Performance Of Modified Polyacrylamide Ice Gel Materials

Cryogels are a macroporous high-molecular polymer with three-dimensional network-like structure synthesized at a frozen state.Different morphologies,different pore structures,and different active site of recognition properties can be obtained by selecting suitable templates,monomers,and cross-linking agents,or using different methods for chemical modification or grafting on the surface of the internal pores of the cryogel.According to their own needs to prepare a variety of cryogel materials.In this paper,we used the method of pending template-imprinting to prepare protein molecularly imprinted cryogel with complex sample bovine serum as template molecules,which have loose macroporous structure,strong mass transfer ability,good mechanical properties and stability.It can deplete the abundance proteins of bovine serum effectively,meanwhile enriched low abundance proteins,providing an efficient and convenient method for the separation of proteins.The polyacrylamide synthesized by the freeze polymerization method emits multicolor fluorescence phenomena through the squeezing effect of ice crystals.Providing a valuable method for the design and synthesis of organic light-emitting materials.We also modified the cryogels by use of co-solvents and surfactants,and adding different luminescent monomers lead to red shift of the fluorescence wavelength and increase the fluorescence intensity.The research content of this article is mainly divided into the following three parts:1.Synthesis of bovine serum imprinted cryogels and deplete of high abundance proteinsMolecularly imprinted polyacrylamide cryogels were synthesized with pending templates(bovine serums of different concentrations).As the serum concentrations increased in the monomer solutions,the resulted protein imprinted cryogels could adsorb and deplete more proteins from serum samples.Due to the addition of vinyltriethoxysilane(VTEOS)in the prepolymerizing solutions,the polymers came as organic-inorganic hybrid materials.It endued the silica-modified amphoteric polyacrylamide cryogels with improved mechanical strengths.Scanning electron micrograph(SEM),infrared(IR)spectrometry,thermogravimetry-differential thermal analysis(TG-DTA),and x-ray photoelectron spectroscopy(XPS)were carried out to characterize these macroporous polymers.Amphoteric cryogels proved to be favorable materials recognizing and binding proteins.When used as liquid chromatography stationary phases,they were capable of simultaneously adsorbing various serum proteins.Electrophoresis exhibited that abundant proteins were gradually depleted by the cryogels prepared from increased ratios of bovine serums in the monomer solutions.This sample per se imprinting method provides an effective and convenient way to deplete abundant proteins from complex samples like serums,meanwhile to concentrate and collect scarce species therein.2.Synthesis and fluorescence properties of polyacrylamide cryogelsBeing short of conventional chromophores,polyacrylamide is generally not regarded as a fluorescent material.Exactly the polymerization of dilute solutions of acrylamide and N,N'-methylenebisacrylamide led to thick liquids at 60?,showing no fluorescence phenomenon.Things changed when the phase transition of water was involved.The squeezing effect of ice crystals allows the prepolymerizing solutions to created polymeric solids(cryogels)at-20? and endowed them unexpected fluorescence emissions properties.The macroporous cryogels are mainly blue fluorescent polymers.However red fluorescence were also achieved by changing the ingredient ratios.A series of instrumental detections revealed that the multicolor fluorescence were based on exquisite amido stacking induced from ice squeezing.If people make good use of the squeezing effect of the heaven-sent molecule to manipulate the interactions of monomer functionalities,cryogenic polymerization can be a promising method to produce diverse polymeric materials.3.Synthesis and fluorescence properties of modified cryogels with different monomersPolyacrylamide was modified with 1-Vinylimidazole and 9-Vinylanthracene as functional monomers.Two types of modified cryogels materials were synthesized from cryogenic polymerization,and characterize them by digital cameras,scanning electron microscope(SEM)and infrared(IR)spectrometry.1-Vinylimidazole has strong dissolving power in water and high icing rate,the resulted modified cryogels obtained from the fluorescence photograph shows that the fluorescence intensity gradually increases with the increase of imidazole amount.The color gradually changes from blue to light green,and the maximum emission wavelength increases from 408 nm to 433 nm,red shift 25nm.9-Vinylanthracene is a hydrophobic monomer that requires the use of ethanol as a cosolvent to promote its dissolution in water.It also requires the addition of the surfactant cetyl trimethyl ammonium bromide(CTAB)to disperse it uniformly.The fluorescence photographs of the resulted modified cryogel has change significantly from green to orange,the maximum emission wavelength of the cryogel material in the green fluorescence picture did not change significantly,and the orange color may not be able to measure its emission spectrum because its fluorescence intensity is too weak.The ice crystals squeezing effect has a great influence on the monomer with strong dissolubility in water,but it has little effect on poor solubility.It is speculated that the possible reason is that their water solubility is different,and ice crystals have different squeezing effects on them.