树枝状大分子与双十二烷基二甲基溴化铵在溶液中的分子间相互作用

Molecular interaction between dendrimer and didodecyldimethylammonium bromide in aqueous solution

通过负染色与冷冻蚀刻透射电子显微镜(TEM)、流变学性能测试等方法,研究了以1.0代聚酰胺-胺(PAMAM)为核心、以(PO)m(EO)n(其中PO与EO分别是环氧丙烷、环氧乙烷的缩写,m和n分别代表嵌段中PO和EO的个数)为辐射臂的树枝状大分子与双十二烷基二甲基溴化铵(DDAB)的分子间相互作用,并将此混合体系的聚集行为、流变学特性与DDAB的囊泡体系进行了比较.研究表明,由于DDAB分子可能插入到树枝状大分子聚集体的疏水微区中,使得混合体系中DDAB类似于凝胶的结构几乎被破坏,随其浓度的增加,混合体系中仅形成了DDAB单层囊泡及其与树枝状大分子构成的复合物,导致剪切后的黏度大幅下降,同时体系几乎不再具有黏弹性特征.

The molecular interaction between dendrimer composed of generation 1.0 poly（amidoamine） （PAMAM） and branched with （PO）m（EO）n （PO and EO are the abbreviations of propylene oxide and ethylene oxide,respectively;m and n are the numbers of PO and EO in a branch,separately） and didodecyldimethylammonium bromide （DDAB） was investigated through negative-staining and freeze-fracture transmission electron microscopy （TEM）,rheology measurements and so forth.Compared with the vesicle system of DDAB,some DDAB molecules maybe insert into the hydrophobic microenvironment of dendrimer aggregates in the mixture of dendrimer and DDAB,resulting in the destruction of the gel-like material feature in DDAB system,which leads to the formation of unilamellar vesicles of DDAB and dendrimer-DDAB complexes.Accordingly,the mixed system hardly possesses the viscoelastic trait any more and the viscosity decrease largely after shearing.