García-Salinas M J, Romero-Cano M S, de las Nieves F J
Complex Fluids Physics Group, Department of Applied Physics, University of Almería, Almería, 04120, Spain.
J Colloid Interface Sci. 2002 Apr 1;248(1):54-61. doi: 10.1006/jcis.2001.8188.
In this work, a study of the thermally induced flocculation of poly(N-isopropylacrylamide/2-acrylamido-2-methylpropanesulphonic acid) microgel, that is, poly(NIPAM/aMPS) microgel samples is presented. The aggregation process is monitored in continuous by dynamic light scattering measurements. Theoretical explanations are considered and discussed in terms of interaction potentials, paying special attention to osmotic and elastic contributions due to particle interpenetration. The rate of aggregation is studied as a function of temperature, and theoretical calculations of kinetic constants based on model core-shell particle interactions provide very good agreement with experimental results. The reversibility of aggregation is also analyzed. It is found that aggregation is completely reversible only under certain conditions: the temperature of an aggregated sample must decrease under 20 degrees C. These results are experimental evidence of the secondary minimum in the interaction potential where aggregation occurs.
在这项工作中，展示了对聚（N-异丙基丙烯酰胺/2-丙烯酰胺基-2-甲基丙烷磺酸）微凝胶，即聚（NIPAM/aMPS）微凝胶样品的热致絮凝研究。通过动态光散射测量连续监测聚集过程。从相互作用势的角度考虑并讨论了理论解释，特别关注由于颗粒相互渗透引起的渗透和弹性贡献。研究了聚集速率与温度的函数关系，基于模型核壳颗粒相互作用的动力学常数理论计算与实验结果非常吻合。还分析了聚集的可逆性。发现聚集仅在特定条件下是完全可逆的：聚集样品的温度必须降至20摄氏度以下。这些结果是相互作用势中发生聚集的二级最小值的实验证据。
