Interactions of polymers, surfactants, bacteria and particle surfaces

溶液或悬浮液中的任何表面都会因其周围溶液中物质的吸附而发生改变。这些物质的吸附极大地改变了表面性质，是各种重要过程的初步步骤。我们对带正电的表面活性剂和聚合物的吸附特别感兴趣，特别是后者可以作为絮凝剂。絮凝——高岭土（粘土）等颗粒的聚集——在造纸和饮用水澄清等过程中很重要。表面活性剂可以吸附在表面上，并可以改变系统的性质，通常是通过溶解对水没有亲和力的物质。因此，表面活性剂的存在会干扰絮凝过程。虽然单一絮凝剂和表面活性剂的作用已经被很好地定义，并且已经在双体系上做了一些工作，但对于含有多种组分的体系，我们知之甚少。我们选择通过检测它们对红外光的吸收来进一步研究这些系统。红外线被吸收的波长对不同的化合物是不同的。我们能够从粘土和其他颗粒的悬浮在甲醇中制备稳定的薄膜，然后使用IR方法来测量感兴趣物种的特征吸光度。这些吸收波长和强度的变化可以告诉我们每种物质吸收到粒子上的方式作为时间的函数，以及它如何与表面上的其他物质相互作用。我们将使用同样的方法来监测油-高岭土聚集体，并研究其表面细菌生物膜的形成，以确定其表面生物膜的形成对油的生物修复是否重要。阳离子聚合物与其他溶解物之间的络合物的形成影响了它们作为絮凝剂的行为。这些配合物将通过它们在应用领域（毛细管电泳）中的运动和它们在高岭土薄膜上吸附的能力来表征，随后进行IR吸光度测量。

Any surface in a solution or suspension will be modified by the adsorption of species from that solution surrounding it. The adsorption of these species dramatically changes the surface properties, and is the preliminary step in a variety of important processes. We are particularly interested in the adsorption of positively charged surfactants and polymers, especially where the latter can act as flocculants. Flocculation - the aggregation of particles such as kaolin (clay)- is important in such processes as papermaking, and the clarification of drinking water. Surfactants can absorb onto surfaces and can change the properties of a system, often by solubilizing substances with little affinity for water. Thus, the presence of a surfactant can interfere with the process of flocculation. Although the actions of single flocculants and surfactants are well defined, and some work has been done on dual systems, much less is known about systems containing multiple components. We have chosen to further study these systems by examining their absorption of infrared (IR) light. The wavelength at which IR light is absorbed is distinctive for different compounds. We are able to prepare stable films of clay and other particles from their suspension in methanol, and then use IR methods to measure absorbances which are characteristic of the species of interest. The shifts in the wavelengths and intensities of these absorbances can tell us about the way each species absorbs onto the particle as a function of time, and how it interacts with other species on the surface. We will use the same approach to monitor oil-kaolin aggregates and study the formation of bacterial biofilms on them, in order to determine whether biofilm formation on their surface is important in bioremediation of the oil. The formation of complexes between cationic polymers and other dissolved species affects their behavior as flocculants. These complexes will be characterized by their motion in an applied field (capillary electrophoresis), and their ability to adsorb onto kaolin films, as followed by IR absorbance measurements.