Lipatov Y, Todosijchuk T, Chornaya V
Institute of Macromolecular Chemistry, National Academy of Sciences of Ukraine, 48 Kharkov Shaussee, Kiev, 02160, Ukraine
J Colloid Interface Sci. 2000 Dec 15;232(2):364-369. doi: 10.1006/jcis.2000.7173.
Adsorption from binary (poly(butyl methacrylate)-CCl(4), poly-styrene-CCl(4)) and ternary (poly(butyl methacrylate)-polystyrene-CCl(4)) solutions has been studied at 10, 25, and 60 degrees C. It was found that with increasing temperature the values of adsorption grew due to worsening of the thermodynamic quality of the common solvent. Worsening of the quality of the solvent leads to a decrease in size of the macromolecular coils and to an increase in the critical concentrations of overlapping macromolecules in solution. As a result, the state of macromolecules in solution depends on temperature and determines adsorption values. From the temperature dependence of adsorption using the Clapeyron-Clausius equation, the differential enthalpy of adsorbate (polymer) DeltaH was calculated for each polymer, by adsorption both from binary solution and from the mixture. Determining DeltaH values from the temperature dependence of adsorption allows us to find this value simultaneously for each polymer in the polymer mixture. It was established that transition of a polymer from solution onto the surface leads to an increase in its enthalpy in the case of adsorption from both binary and ternary solutions. DeltaH increases with increasing coverage of the surface. By transition from solution onto the surface, the enthalpy of the adsorbed polymer increases; i.e., the polymer transits in an energetically less favorable state. This effect is more pronounced for adsorption from the mixture, which may be connected with the presence of the second polymer in the adsorption layer. Copyright 2000 Academic Press.
研究了二元（聚甲基丙烯酸丁酯 - 四氯化碳、聚苯乙烯 - 四氯化碳）和三元（聚甲基丙烯酸丁酯 - 聚苯乙烯 - 四氯化碳）溶液在10℃、25℃和60℃下的吸附情况。发现随着温度升高，由于共同溶剂热力学性质变差，吸附值增大。溶剂性质变差导致大分子线团尺寸减小，溶液中大分子重叠的临界浓度增加。因此，溶液中大分子的状态取决于温度并决定吸附值。利用克拉佩龙 - 克劳修斯方程根据吸附的温度依赖性，计算了每种聚合物从二元溶液和混合物中吸附时吸附质（聚合物）的微分焓ΔH。根据吸附的温度依赖性确定ΔH值，使我们能够同时求出聚合物混合物中每种聚合物的该值。已确定，在从二元溶液和三元溶液吸附的情况下，聚合物从溶液转移到表面会导致其焓增加。ΔH随表面覆盖率增加而增大。通过从溶液转移到表面，吸附聚合物的焓增加；即聚合物转变为能量上较不利的状态。这种效应在从混合物吸附时更为明显，这可能与吸附层中存在第二种聚合物有关。版权所有2000年学术出版社。
