光照可逆调控侧链液晶聚合物膜的表面能

对侧链液晶聚合物聚甲基丙烯酸(5-[4-(4-氰基偶氮苯)苯氧基]戊酯)进行溶液铸膜,用473nm线偏振光(LPL)照射使聚合物膜发生光致取向,用锥光成像的方法表征了侧链液晶聚合物的取向。取向前接触角为71.8°,取向后为86.4°;用365nm紫外光照射后,薄膜发生了解取向,解取向后接触角为72.3°。取向使膜表面能由40.1变为30.8mJ/m2,解取向后又恢复到39.8mJ/m2。表明光照能可逆调控侧链液晶聚合物表面能。

Light-induced reversible changes the surface energy of side-chain liquid crystalline polymer film

Light-induced orientation and disorientation of an azobenzene containing side-chain liquid crystalline polymer poly(5-[4-(4’-cyano-azobenzene) phenoxy]pentyl methacrylate) were conducted on a solution-cast film.When exposed under a vertical linearly polarized light(LPL) at 473nm,in-plane orientations of the mesogens were induced and were confirmed by the POM observations under conoscopic and orthoscopic illuminations.The contact angles of a drop of water on the different orientated films were measured of 71.8 and 86.4° on the non orientated and orientated film,respectively.The disorientated film was obtained by irradiated the orientated film upon exposed with a 365nm UV-light.The contact angle of a drop of water on the disoriented film is 72.3°.The surface energy of thin film was further calculated according to the measured contact angles,which reversibly varied between 40.1 and 30.8mJ/m2.