利用水滴模板法成功制备出孔径可控的具有结构规则的聚合物多孔膜,并以所制备多孔膜为模板利用反向复刻法复制孔洞阵列结构,得到具有微米级突起阵列结构的聚二甲基硅氧烷(PDMS)膜片,然后将事先排布好的二氧化硅微球阵列通过热压印法转移到具有微米级突起结构的PDMS膜片上,然后成功制备出具有微纳米复合突起结构的膜片。通过对具有不同突起结构组合的PDMS膜片进行接触角测试发现,膜片的接触角随着其表面粗糙程度的增大而增大,即具有微纳复合结构膜片接触角((150.7±3.2)°)最大,达到了超疏水的效果;无突起结构膜片的接触角((108.9±3.1)°)最小;而仅具有微米级结构膜片的接触角((134.6±1.0)°)居中,这符合目前已知的物质表面浸润性与其表面粗糙度的关系。另外,经测试,具有微纳复合结构的膜片接触角最大达到155°,同时具有非常大的滚动角,使得这种膜片材料具备了粘性超疏水的性能,而这种特殊浸润表面性质可以在液体无损传输、生化分离等领域拥有巨大的应用前景。
A facial way to fabricate composite-structured polydimethylsiloxane (PDMS) film with both micro- and nano-sized structures was reported here in details. A porous polymer film with regular pore arrays was firstly prepared as structural template following the typical procedure of breath figures (BF) method. The micro-structured PDMS substrate was then prepared by molding from the BF template. And regular arrays of monodispersed silica particles were further stamped onto the surface of micro-structured PDMS film to obtain the composite-structure. The results of the water contact angles (WCAs) of the PDMS films with different levels of structures reveal that the hydrophobicity of the materials increases with the increasing roughness of the surface, which fits the commonly known conclusion. Moreover, the WCA of the composite-structured PDMS film could reach up to 155°. And it also possesses ultra-high water rolling angle, showing the so called sticky superhydrophobicity. Such property has many potential applications ranging from loss-free transmission to biochemical separation.