环形侧链聚合物刷的合成与表征

Synthesis and Characterization of Cylindrical Polymer Brushes with Cyclic Side-chains

通过grafting-onto方法合成高侧链接枝密度的环形侧链聚合物刷并进行结构表征.先通过开环易位聚合(ROMP)制备带有炔基侧基的线形聚降冰片烯衍生物主链(l-PND),通过原子转移自由基聚合(ATRP)和铜催化的叠氮-炔环加成(Cu AAC)反应制备带有一个叠氮基的环形聚丙烯酸叔丁酯侧链(c-Pt BA),再利用Cu AAC反应将环形侧链高密度地接入主链,得到环形侧链聚合物刷.通过核磁氢谱(1H-NMR)、凝胶渗透色谱(GPC)和红外光谱(IR)对聚合物主/侧链及聚合物刷的结构和组成进行了表征.该聚合物刷主链聚合度为400,高接枝密度的环形侧链使主链构象伸展.聚合物刷在原子力显微镜(AFM)下呈单分子蠕虫形貌(柱状形貌),分子长度为200 nm,直径为30 nm.

Cylindrical polymer brushes with densely grafted cyclic side-chains are synthesized via the graftingonto method. The structure and composition of the polymers are well characterized. Linear polynorbornylene derivative（ l-PND） backbones containing alkynyl groups are prepared by ring opening metathesis polymerization（ ROMP）,and cyclic poly（ tert-butyl acrylate） side-chains（ c-Pt BA） containing azide groups are synthesized by the combination of atom transfer radical polymerization（ ATRP） and copper catalyzed azide-alkyne cycloaddition（ Cu AAC） reaction. Then,the cyclic side-chains are grafted densely onto the backbone by Cu AAC reaction to form a cylindrical polymer brush. The structures of the polymers were characterized by1H-NMR,gel permeation chromatography（ GPC） and infrared（ IR） spectroscopy. The obtained polymer brush has a long backbone of 400 degree of polymerization. The densely grafted side-chains lead to extension of the backbone. A single molecule of the polymer brush shows a wormlike（ cylindrical）morphology observed by the atomic force microscopy（ AFM）. The length of the polymer brush is 200 nm,and the diameter is 30 nm. The polymer brush with cyclic side-chains is observed as a wormlike molecule for the first time,which has great reference value to study the influence of the topological structure（ backbone and side-chains） on the morphology of the polymer brushes.