聚丙烯酰胺凝胶吸水膨胀驱动行为

Actuating Behavior of Polyacrylamide Hydrogels in the Process of Absorbing-Water

目的研究聚丙烯酰胺凝胶在吸水膨胀过程中的驱动行为,为实现智能凝胶的精确控制以及进一步应用奠定基础.方法常温条件下制备聚丙烯酰胺凝胶,通过微机控制的力学试验机测试其不同含水量时的应力-应变曲线,采用预压重物的方法测试聚丙烯酰胺凝胶在束缚状态下的吸水膨胀过程及对其外膨胀做功的能力.结果不同初始尺寸的凝胶在实际吸水膨胀过程中与理论预测出现偏差,不同尺寸试样的膨胀驱动做功能力也有显著差异.结论聚丙烯酰胺凝胶在实际应用中的吸水膨胀驱动行为,可看作是在自身重力和外界压力共同作用下的束缚膨胀做功过程,与试样的初始尺寸(长径比)、外界压力有密切关系.

Hydrogels exhibit the smart characteristics of changing their volume up to many times corresponding to the external stimulus. Control for actuating behavior of hydrogel in absorbing - water process has been a key issue for the commercial application of hydrogels as smart actuators. In this paper, the polyacrylamide （PAM）hydrogels were synthesized by conventional method, and their actuating behaviors in the process of absorbing - water were investigated. It was found that there were obvious differences in the swelling behaviors for those PAM hydrogels with different aspect ratios. Such a deviation from the theoretical forecast of swelling behaviors was mainly associated with the difference in the initial sizes for those hydrogels. Moreover, the output work for those swelling hydrogels was strongly dependent on the sample sizes, external force, and so on. An accurate control for actuating behavior of hydrogel can be obtained by designing the hydrogel structures with considerations of the applied force.