CNCs增强相分离法构建PVDF/PDMS超疏水表面

Construction of PVDF/PDMS superhydrophobic surface by CNCs enhanced phase-separation

采用非诱导相分离法,将纤维素纳米晶(CNCs)与两种聚合物(聚偏二氟乙烯和聚二甲基硅氧烷)进行结合,利用CNCs之间的静电排斥力及其大比表面积特性有效降低相分离过程中聚合物的聚集,减小了粒子尺寸,增强了粒子分散性,在棉布、木板和玻璃表面构造了精细、均匀的微纳米粗糙结构。采用FTIR、SEM、AFM、接触角测量仪、3D光学轮廓仪对CNCs和超疏水表面的形貌、结构和超疏水性进行了表征。结果发现,棉布、木板和玻璃表面的水接触角最高分别可达158.0°、156.8°和153.8°,滚动角最低分别为2.0°、2.7°和3.4°,呈现出明显的超疏水特征。经过机械摩擦(约500次)、酸碱处理(pH 1~13)、温度变化(–40~40℃)以及紫外光照射(0~320 h)后,基材表面仍具有较好的超疏水性。此外,基材具有优异的自清洁性和油水分离效率,超疏水棉布的最高分离效率可达98.4%。

Fine and uniform micro-nano rough structures were constructed on the surface of cotton cloth,wood board and glass via non-induced phase separation method by combination of cellulose nanocrystals(CNCs)with two polymers(polyvinylidene fluoride and polydimethylsiloxane).Both the aggregation between polymers and particle sizes were effectively reduced during the phase separation owing to the electrostatic repulsion between CNCs and their high surface area.The morphology and structure of the CNCs and superhydrophobic surfaces were characterized by FTIR,SEM,AFM,contact angle measuring instrument and 3D optical profilometer.It was found that the highest water contact angles of cotton cloth,wood board and glass surface were 158.0°,156.8°and 153.8°,respectively,and the lowest rolling angles were 2.0°,2.7°and 3.4°,respectively,clearly indicating superhydrophobic characteristics.The superhydrophobicity of the substrate surface was retained very well after mechanical friction(over 500 times),acid-base treatment(pH 1~13),temperature change(–40~40℃)and ultraviolet irradiation(0~320 h).In addition,the substrates exhibited excellent self-cleaning and oil-water separation efficiency,with the superhydrophobic cotton cloth showing maximum separation efficiency of up to 98.4%.