含Gemini表面活性剂结构单元的新型两亲聚电解质的合成及聚集行为

Synthesis and Self-aggregation Behavior of Novel Amphiphilic Polyelectrolytes Containing Gemini Surfactant Units

分别将Gemini型单体1,3-双(二甲基十四烷基溴化铵)-2-丙烯酰氧基丙烷(14G)或1,3-双(二甲基十六烷基溴化铵)-2-丙烯酰氧基丙烷(16G)与丙烯酰氧乙基三甲基氯化铵(DAC,D)共聚合反应,合成了新型含Gemini表面活性剂结构单元的两亲性阳离子聚电解质(D14G和D16G).采用稳态荧光、电导、动态光散射及透射电镜等手段研究了这些聚电解质在水溶液中的聚集行为.结果表明,临界聚集浓度(CAC)随着Gemini型表面活性剂单元含量的增加而减小,同时随着Gemini型表面活性剂单元中疏水碳链长度的增加而降低.这些聚电解质在水溶液中同时存在分子内和分子间两种类型的聚集体,而且碳链越长,形成分子内聚集体的倾向越强.随着Gemini表面活性剂单元含量的增加,D14G溶液中聚集体的流体动力学半径(Rh)也有所增大,而D16G溶液中的聚集体的流体动力学半径(Rh)却略有减小.

A novel class of amphiphilic polyelectrolytes bearing Gemini surfactant units were synthesized using the copolymerization of acryloyloxyethyltrimethylammonium chloride（D） and Gemini surfactant type monomer 1,3-bis（N,N-dimethyl-N-alkylammonium）-2-proplylacrylate dibromide（G）（alkyl = tetradecyl or cetyl）.The self-aggregation properties of these polyelectrolytes in aqueous solution were investigated by steady fluorescence,conductivity,dynamic light scattering（DLS） and Transmission electron microscopy（TEM） techniques as the function of the molar fraction of Gemini surfactant units in the polyelectrolyte.It was found that the critical aggregation concentration（CAC） decreases with the increase of molar fraction of Gemini surfactant segments and the length of alkyl chain on the Gemini surfactant units.Two kinds of aggregates coexist in the solution,one of which is suggested to be intrapolymer aggregate and the other is interpolymer aggregate.With the increase of alkyl chain length,the polyelectrolytes exhibit a strong preference for intrapolymer hydrophobe selfaggregation.With the increase of molar fraction of Gemini segments,the hydrodynamic radius（Rh） increases in the case of D14G and oppositely decreases slightly in the case of D16G.