School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
Langmuir. 2012 Apr 17;28(15):6282-90. doi: 10.1021/la300282m. Epub 2012 Apr 2.
The effects of a nonionic alcohol ethoxylate surfactant, C(13)E(7), on the interactions between PVP and SDS both in the bulk and at the silica nanoparticle interface are studied by photon correlation spectroscopy, solvent relaxation NMR, SANS, and optical reflectometry. Our results confirmed that, in the absence of SDS, C(13)E(7) and PVP are noninteracting, while SDS interacts strongly both with PVP and C(13)E(7) . Studying interfacial interactions showed that the interfacial interactions of PVP with silica can be manipulated by varying the amounts of SDS and C(13)E(7) present. Upon SDS addition, the adsorbed layer thickness of PVP on silica increases due to Coulombic repulsion between micelles in the polymer layer. When C(13)E(7) is progressively added to the system, it forms mixed micelles with the complexed SDS, reducing the total charge per micelle and thus reducing the repulsion between micelle and the silica surface that would otherwise cause the PVP to desorb. This causes the amount of adsorbed polymer to increase with C(13)E(7) addition for the systems containing SDS, demonstrating that addition of C(13)E(7) hinders the SDS-mediated desorption of an adsorbed PVP layer.
通过光子相关光谱法、溶剂弛豫 NMR、小角中子散射和光反射测量研究了非离子醇乙氧基化物表面活性剂 C(13)E(7)对 PVP 和 SDS 之间在本体和二氧化硅纳米颗粒界面相互作用的影响。我们的结果证实，在不存在 SDS 的情况下，C(13)E(7)和 PVP 不相互作用，而 SDS 与 PVP 和 C(13)E(7)均强烈相互作用。研究界面相互作用表明，可以通过改变 SDS 和 C(13)E(7)的量来操纵 PVP 与二氧化硅的界面相互作用。在 SDS 加入后，由于聚合物层中胶束之间的库仑排斥作用，PVP 在二氧化硅上的吸附层厚度增加。当 C(13)E(7)逐渐加入到体系中时，它与复合 SDS 形成混合胶束，从而降低每个胶束的总电荷，从而降低胶束与二氧化硅表面之间的排斥作用，否则会导致 PVP 解吸。这导致含有 SDS 的体系中随着 C(13)E(7)的加入，吸附聚合物的量增加，表明 C(13)E(7)的加入阻碍了 SDS 介导的吸附 PVP 层的解吸。
