Conformation and Kinetics in Polyelectrolyte Adsorption

9414289本课程将研究聚电解质在固/液和液/液界面上的吸附动力学和等温线。表面氧化还原基团衍生的金属表面将被用来精确地控制表面电荷，以努力将聚合物的构象和覆盖度与表面电荷密度联系起来。这些“智能”氧化还原活性表面将被用来确定吸附是受热力学还是动力学控制。合成了放射性标记的亲水/疏水共聚物，如苯磺酸盐/丁基苯乙烯，并研究了它们在两种不相容液体界面上的吸附。对于吸附的聚电解质，将测量平均线圈半径与盐浓度的关系，并与众所周知的溶液聚电解质尺寸与屏蔽长度的关系进行比较。两嵌段共聚物将被吸附在固/液和液/液界面上，并且它们在这两个界面上的表面覆盖率将被比较，并与疏水表面锚固块的迁移率相关。在零电场条件下，将测量聚电解质在相反电荷凝胶中的吸收，以确定带电大分子渗透到带电基质中的程度和动力学。聚电解质的%吸附是处理用于环境目的的水(饮用水、城市和工业废水等)的关键步骤。这项研究将提供与各种吸附理论相关联的重要实验。

9414289 Schlenoff Kinetics and isotherms of the adsorption of polyelectrolytes to solid/liquid and liquid/liquid interfaces will be investigated. Metal surfaces derivatized with surface-attached redox groups will be employed to control the surface charge precisely in an effort to relate polymer conformation and coverage to surface charge density. These "smart" redox-active surfaces will be used to ascertain whether adsorption falls under thermodynamic or kinetic control. Radiolabelled hydrophilic/hydrophobic copolymers, such as styrene sulfonate/butyl styrene, will be synthesized and their adsorption at the interface between two immiscible liquids will be studied. For adsorbed polyelectrolytes, the dependence of average coil radius on salt concentration will be measured and compared with the well-known dependence of solution polyelectrolyte dimensions on screening length. Diblock copolymers yielding brush-type morphologies will be adsorbed at the solid/liquid and liquid/liquid interfaces and their surface coverages at these two interfaces will be compared and related to the mobility of the hydrophobic surface-anchoring block. Absorption of a polyelectrolyte into an oppositely- charged gel will be measured to determine the extent and kinetics of penetration of a charged macromolecule into a charged matrix under conditions of zero applied electric field. %%% Adsorption of polyelectrolytes is the critical step in the treatment of water for environmental purposes (drinking water, municipal and industrial effluents, etc.). This research will provide important experiments that can be correlated with various adsorption theories.