Study On The Synthesis Of Cucurbit[6]Uril-based Stimulus Response Polymers And Their Properties

In this paper,cucurbit[6]uril was successfully introduced into the polymer system by radical polymerization.Then CB[6]-based multi-stimulus response polymers were successfully prepared and their properties were studied.The paper is mainly divided into the following sections:（1）Firstly,hydroxycucurbit[6]uril was obtained from cucurbit[6]uril by H₂O₂ photochemical oxidation.And CB[6]-methacrylate monomer is further synthesized by nucleophilic addition reaction.CB[6]-based multi-stimulus response random copolymers were successfullypreparedbyfreeradicalpolymerizationof CB[6]-methacrylate monomer with N-isopropyl acrylamide.The structures of the copolymers were characterized by ¹H-NMR,IR spectra and static light scattering,and the morphology was observed by TEM and SEM.In addition,the effects of pH,external salt,guest molecules,and CO₂on responding chracteristics were studied in detail.The results shows that the lowest critical temperature（LCST）of the copolymers is affected by the pH,external salt,guest molecules,and CO₂ due to the presence of the CB[6]macrocycle molecule.Therefore,the stimuli response characteristics of the copolymer can be controlledby controlling the content of CB[6]and solution aggregation conditions.It was observed by TEM that the structure of copolymer was nanosphere in the water;the aggregation morphology of the copolymer was successfully changedafter adjusted by pH and NaCl.We studied the characteristic of the copolymer as a drug carrier in the further experiment,and the methyl orange was used as a model molecule on the study of the inclusion’s release in this chapter.The slow release of stimulation can be achieved by changing the environmental conditions.The final result shows that the system has better characteristic on sustained release.We prepared CB[6]-based copolymers by free radical polymerization of CB[6]-methacrylate monomer with N-vinylcaprolactam,which is also a monomer has sensitivity on temperature.The structure was characterized by ¹H-NMR,IR spectra and GPC.It has been found that the presence of CB[6]has a significant effect on the temperature sensitivity of polymers through preliminary studies.This part work is being further improved.（2）The CB[6]-based rotaxane monomer with double bonds wasobtained by the reaction of CB[6]and organic ammonium ions through the interaction of ion-dipole and hydrophobic.The CB[6]-based rotaxane monomer was used to prepared smart copolymers by the free-radical copolymerization.We used CB[6]as raw material on the synthesis of monomer butylammonium acrylate/CB[6]rotaxane by interacting with the host-guest of acrylic acid and n-butylamine.Then CB[6]-based multi-stimulus response polymers were successfully prepared with butylammonium acrylate/CB[6]rotaxane and N-isopropylacrylamideby redox polymerization.The structures of the polymers were characterized by ¹H-NMR,IR spectra and static light scattering,and the morphologies were observed by TEM and SEM.In this chapter,the effects of pH,external salt,etc.on the response performance of polymer stimuli were studied in detail.The result shows that the LCST of the copolymers is affected by the copolymer concentration,pH and NaCl content.The SEM and TEM demonstrate that the copolymer was in the form of nanovesicle and the change in the morphology of the polymer can be regulated by changing the conditions of aggregation.Considering the properties of the copolymer,this material has great application prospect in the field of drug delivery and release.Then,we used CB[6]as raw materials to synthesize the CB[6]-hexamethylenediamine bisacrylic acidby the interaction with host-guest of acrylic acid and hexamethylenediamine.Then,the CB[6]-based stimuli-responsive polymer vesicle was successfully preparedwith free radical polymerization with N-isopropylacrylamide.It was found that the Solution property of polymer was affected by thepolymer concentration,pH,and NaCl.The SEM and TEM demonstrated that the copolymer was a nanovesicle and the copolymer vesicles were destroyedafter mediated by NaOH（p H=11.53）.