温度敏感型高分子膜特性在线测试新方法的研究

Study a Novel Measuring Method for Evaluating Property of Temperature-Sensitive Polymer Gel Membrane In-Situ

温度溶胀性是温度敏感型高分子膜作为智能感应材料的关键特性。研究提出用压电悬臂梁换能器在溶液中在线测试高分子膜的温度溶胀特性。该测试装置由集成压电元件的悬臂梁和高分子膜探针两部分组装而成。高分子膜可以采用不同的化学处理方法固定在探针上。悬臂梁压电元件将高分子膜微小质量的变化转化为压电元件电气阻抗的变化。首先用有限元分析方法和实验方法校准自制压电悬臂梁的频率特性,从理论上得出压电导抗的频率变化与高分子膜质量变化的关系;然后用此装置在溶液中测试了粘贴膜和涂敷膜的温度溶胀特性;结果清晰地表明了高分子膜的低温亲水性和高温疏水性。压电悬臂结构换能器能具有在线正确地测定高分子膜的温度溶胀特性,具有很好的应用前景。

Swelling ratio is an important characteristic of temperature-sensitive poly （N-isopropylacrylamide） gel membrane as smart material This study is concerned with the development of a cantilever transducer patched with a piezoelectric element for evaluating swelling ratio of temperature-sensitive polymer membrane in situ. The transducer consists of an aluminum cantilever beam patched with a piezoelectric ceramics and a probe coated by polymer gel membrane. Polymer membrane can be fixed on the probe in different ways. The electric impedance of piezoelelctric element is changed with the polymer small mass change. First, the characteristic of the piezo-cantilever transducer is criteria by experiment and simulated with the aid of the Finite Element Method. The relation between the natural frequency change of the transducer and absorbed mass of the polymer gel membrane is obtained theoretically. The experiments are conducted in liquid to measure the swelling ratio of pasted polymer and coating membrane. Temperature-sensitive polymer membrane characteristics of hydrophilic-hydrophobic can be explained clearly by the results. The results also show piezo-cantilever transducer has the potential in application for detecting polymer gel membrane characteristics conveniently and accurately in situ.