界面扩张流变法研究部分水解聚丙烯酰胺与表面活性剂相互作用

Studies on the Interactions between Partially Hydrolyzed Polyacrylamide and Surfactants by Interfacial Dilational Rheology

利用界面扩张流变方法研究了部分水解聚丙烯酰胺(HY)和阴离子(SDS)、非离子型表面活性剂(Brij-35、TX-100)在十二烷-水界面上的扩张流变性质,探讨了油/水界面上聚合物与表面活性剂不同的相互作用方式和机理。结果表明,HY+TX-100体系的界面模量最小(约3 mN/m),HY与HY+Brij-35体系相当(约16 mN/m),HY+SDS体系的略高(约18 mN/m)。阴离子表面活性剂(SDS)带负电荷的头基、聚合物的羧基与矿化水中高价金属阳离子通过桥连作用在油水界面形成复合膜,导致界面膜强度增加。而非离子表面活性剂与部分水解聚丙烯酰胺的静电相互作用较弱,不易形成界面复合膜。在油水界面吸附能力较强的表面活性剂分子(TX-100)足以替换聚合物大分子,形成小分子界面膜,表现出与复合膜完全不同的界面流变性质。

The interactions between a partially hydrolyzed polyacrylamide（HPAM） and three types of surfactants including anionic and nonionic ones at dodecane/water interface were studied,respectively,by using interfacial dilational rheology,and the interactions and mechanisms between them were also discussed.It was indicated that,the value of viscoelastic modulus was arranged as follows： HY＋TX-100 system（3 mN/m）HY system≈HY ＋ Brij-35 systme（16 mN/m） HY＋SDS system（18 mN/m）.Based on the results,the strong complex film was formed by the electrostatic interaction between carboxyl groups of HPAM and the negatively charged ions of the anionic surfactant SDS via high-valent metal ions.However,the interactions between nonionic surfactant and HPAM were too weak to form complex film.Some nonionic surfactant,such as TX-100,with strong adsorbability at the oil/water interface,could displace HPAM and form small molecule films,which exhibited different interfacial dilational rheology.