相对分子质量对含多巴胺氢键薄膜的组装行为和结构的影响

Effect of Molecular Weight on the Assembly Behavior and Structure of Hydrogen-Bonded Film Contained Dopamine

以多巴胺改性的聚丙烯酸(PAA-dopa)和聚乙烯基吡咯烷酮(PVPON)为组装物,在氢键作用下,通过层层组装技术成功制备了PVPON/PAA-dopa薄膜。其中,PAA-dopa和PVPON分别作为氢键给体和受体,PAA-dopa上的羧基和酚羟基均可与PVPON上的羰基形成氢键,并研究了组装物相对分子质量对组装行为的影响。结果表明:具有较低相对分子质量的PAA-dopa以较舒张的链构象参与组装,与PVPON组装可获得较为光滑的薄膜;随着PAA相对分子质量的增大,PAA-dopa分子内氢键作用增强,以紧密的链构象参与组装,形成疏松粗糙的薄膜,薄膜厚度随之增大;而不同相对分子质量的PVPON与PAA-dopa进行层层组装均可获得结构规整且表面光滑的薄膜;随着相对分子质量的增大,PVPON分子链移动性减弱,薄膜的厚度逐渐降低。

The thin PVPON/PAA-dopa film was fabricated through layer-by-layer assembly of dopaminemodified poly(acrylic acid)(PAA-dopa)and poly(vinylpyrrolidone)(PVPON)based on hydrogen bonding.PAA-dopa and PVPON were acted as the hydrogen bond donor and acceptor,respectively.Both the carboxylic group and phenolic group of PAA-dopa could form hydrogen bond with the carbonyl group of PVPON.The influence of molecular weight on the assembly behavior of the layer-by-layer film was studied.The results show that PAA-dopa with relatively low molecular weight is assembled at the expanded chain conformation,thus a relatively smooth thin film is formed.With the molecular weight increases,the intra-molecular hydrogen bonding of PAA-dopa enhances,and it is assembled at the compact conformation.Thus,the film is rough and has a relatively high thickness.For PVPON with different molecular weights,all the films show regular and smooth surface morphologies.With the molecular weight increases,the mobility of the PVPON chain reduces,the thickness decreases gradually.