Superhydrophobic hierarchical structures produced through novel low-cost stamp fabrication and hot embossing of thermoplastic film

We present a simple and cost-effective method to produce superhydrophobic surfaces in thermoplastic polymer substrates, which contain hierarchical micro/nano structures that resemble lotus leaves. The method involved the fabrication of an Al stamp through the sequential application of laser ablation and anodization to create micro- and nano-structures, respectively. The fabricated patterns on the Al stamp were replicated on the thermoplastic Cyclic olefin copolymer (COC) film surfaces through a hot embossing technique. Static water contact angles were measured to evaluate the hydrophobicity of the patterned COC surfaces. The static water contact angle on the micro/ nano hierarchical structured COC surface was measured to be 162.3A degrees on average. The hot embossing process was repeated 31 times with a nano-structured Al stamp, and the replicated COC surfaces showed consistent water contact angles.