Study On Polymerization-Induced Self-Assembly Of Salicylic Acid Polymer

The traditional preparation of polymer nano-aggregates is completed in two steps.Firstly,the polymer chains are synthesized and purified,and then the polymer chains are assembled by direct dissolution or solvent switching,which is cumbersome to operate.In recent years,researchers have explored polymerization-induced self-assembly,which takes only one step to prepare polymer nano-aggregates.Using hydrophilic macromolecules as initiators,the polymerization reaction is carried out in a solvent in which the hydrophobic segment monomer is soluble but the hydrophobic segment polymer is insoluble in a certain degree of polymerization With the polymerization reaction,the self-assembly process is synchronized with the increase of the degree of polymerization of the hydrophobic segment.Its operation is simple and easy to prepare,and it has been widely used in various controllable polymerization,such as RAFT polymerization,ATRP polymerization,NMR polymerization,etc.The polymerization product of N-carboxylic anhydride(NCA)monomer has a polyamino acid structure,which has certain applications in biomedicine and other fields.The polymerization product of Ocarboxylic anhydride(OCA)monomer has a polyester structure,which provides potential degradability.In recent years,there have been a few reports of NCA polymerization induced self-assembly,but no reports of OCA polymerization induced self-assembly.Therefore,it is particularly important to synthesize a degradable nano-aggregate induced by OCA polymerization.In this paper,salicylic acid with anti-inflammatory and antioxidant properties was selected as raw material to synthesize salicylic acid O-carboxylic anhydride(SAOCA)monomer,and bio-compatible mPEG2000-OH was used as macromolecular initiator in selective solvent to study SAOCA polymerization induced self-assembly.after optimizing the reaction conditions,BEMP,3,5-bis(trifluoromethyl)phenyl-3-phenylurea,The molecular weight of the polymer is 7.5 KDa and the molecular weight distribution is 1.18 when the molar ratio of mPEG2000-OH and SAOCA is 0.25/1/1/50.it is an mPEG2000-b-PSA diblock polymer by NMR analysis.After that,the controllability study of polymerization proves that it is controllable polymerization.The self-assembly process was traced by UV test and TEM test,which proved that the polymerization induced self-assembly process occurred...