Fabrication of polyethylene surface with stable superhydrophobicity by nanoparticle assisted thermal micromolding process

Superhydrophobic surface with lotus leaf effect has many practical and potential applications in different fields. In this paper, a novel process based on nanoparticle assisted thermal micromolding was developed to create polyethylene superhydrophobic surface. Briefly, a thin layer of TiO2 nanoparticles was first coated on the featured surface of the poly(dimethylsiloxane) (PDMS) stamp replicated from a fresh lotus leaf. Then low-density polyethylene (LDPE) was thermally pressed onto such TiO2 coated stamp. A control process was also performed by thermally pressing TiO2/LDPE nanocomposite material onto a blank PDMS stamp. Scanning electron microscopy (SEM) imaging and contact angle measurements showed that the surfaces of LDPE films replicated from stamp coated with TiO2 had more delicate nano-structures and higher water contact angles (> or = 155 degrees) than those replicated from the blank stamp. Moreover, the superhydrophobic surface formed by TiO2 assisted micromolding was relatively stable under water stream with high pressure. This study shows that nanoparticle assisted micromolding is an alternative technique to other techniques for large scale production of superhydrophobic polymeric films.