静电纺丝制备具有浸润性梯度的聚酰亚胺纳米纤维膜

采用高压静电纺丝技术, 在非对称异型电极上制备得到放射状聚酰亚胺(PI)纳米纤维膜. 采用环境扫描电子显微镜(ESEM)观察了PI膜的微观形貌以及纳米纤维的排列状态; 采用接触角测量仪研究了水滴浸润性的变化; 采用高敏感性力学微电力学天平测量了水滴的黏附力, 分析了微观形貌变化与水滴浸润性质和黏附性质的关系. 结果表明, 该PI纳米纤维膜沿着非对称异型电极三角电极至弧型电极方向纤维排列由密到疏, 呈放射状, 具有独特的微结构梯度; 整个纤维膜上的PI纳米纤维直径均一且具有光滑均匀表面, 纤维与纤维之间的距离约为几微米到几十微米. 由于PI纳米纤维膜所具有的独特的微结构梯度, 致使沿着微结构梯度方向水滴的接触角(从超疏水到疏水)和黏附力(从低黏附到高黏附)均表现出梯度变化的特征.

Preparation of Polyimide Nanofiber Membrane with Gradient Wettability by Electrospinning

Radial polyimide(PI) nanofiber membrane was prepared on an asymmetric electrode by electrospinning.The morphology and arragement of the nanofiber on the PI membrane were observed by environmental scanning electron microscope(ESEM).The wettability was characterized by the apparent contact angle and the surface adhesive effect was characterized by the high-sensitivity microelectromechanical balance system.The effect of the microstructures on the contact angle and adhesive force was analyzed.The experimental results show that the PI nanofibers exhibit novel gradient microstructures.Particularly,the PI nanofibers were in a radial pattern from dense to sparse along the direction of triangular electrode to curved electrode.The diameter of the PI nanofibers was uniform and their surfaces were smooth.The distance between the adjacent fibers was from a few microns to tens of microns.The unique gradient microstructure of PI nanofiber membrane results in the gradient density of the surface chemical substance and they are crucial to the gradient changes of the contact angle and adhesive force.