| The amphiphilic polymer is a special molecule with both hydrophilic sides and lipophilic sides. It possessed particular specificity in surface properties because both hydrophilic sides and lipophilic sides tended to be separated from micro-phase. Therefore, more and more attention has been paid to researching amphiphilic polymers.Polyethylene glycol (PEG) is a common biochemical drug. Not only does PEG have high hydrophilia, it also has properties of low toxicity, and has been widely used in the synthesis of special biological polymers and modifying amphiphilic polymers. Cholesterol is an organic compound with a rigid steroid structure, which has been usually used in the study of polymer hydrophobic. Both polyethylene and cholesterol have good biocompatibility, and can form a lipid monolayer that is similar to biological monolayer in the gas-liquid interface spontaneously if combined together. In this case, they can be used in the area of drug carrier technology, drug slow-releasing technology, solubilization of indissolvable drugs and so on.In this paper, a series of amphiphilic polymers were synthesized by Atom Activators Regenerated by Electron Transfer Atom Transfer Radical Polymerization (ARGET ATRP) using cholesteryl chloroacetate as initiator, CuCl/PMEDTA as catalyst system, anisole as the solvent and polyethylene glycol monomethyl ether acrylate as monomer, in the condition of different temperatures and different reaction time. In addition, Langmuir monolayer technologies were used to study the interaction between monolayer of polymer product and the fixed film of polymer product with phospholipid. Their surface properties were studied by the π-A isotherms that was gained through Langmuir-Blodgett film balance.The conclusions areas followed:(1) The structure and composition of initiator was characterized by infra-red(IR), nuclear magnetic resonance spcctroscopy (Il'NMR) as well as melting point test.It can be also found that the best result came when benzene was used as solvent, and4-dimethyl-aminopyridine was used as acylating agent. (2) The structure and composition of monomer was characterized by IR and H'NMR.It can be also found that the best result came when reaction time was7h, and molar radio of triethylamine/acryloyl chloride/polyethylene glycol monomethyl ether was73:23:8.5.(3) The structure and composition of product were characterized by IR as well as H'NMR.The molecular weights and the molecular weights distribution were characterized by gel chromatography (GPC). The GPC showed that the monomer conversion increased as the temperature became higher, and In ([M] o/[M]) and reaction time showed a linear relationship. At the same time, the monomer conversion also increased over time, and molecular weights became larger gradually. It could be also found that the molecular weight distribution changed from wide to narrow, and the final Index of Polymer Distribution (PDI) were all less than1.5, which showed that the whole reaction can be seen as living polymerization with good controllability.(4) The LB film balance was used to compress polymer product with different molecular weight or different length of PEG to gain π-A isotherms. The isotherms were discussed by The Scaling Law, and showed the length had strong effect on the properties of phospholipid film.That is as the content of PEG decreased, the tightness of film increased obviously, and the limit molecular occupies area decreased, too.(5) The LB film balance was also used to compress polymer product with different molecular weight or different length of PEG mixed with phospholipid. The isotherms showed that the m-PEG polymer product had been interacted with phospholipid.After the interaction, the stability of phospholipid enhanced significantly. The stability increased obviously as the PEG chain became longer. |
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