Superhydrophobic surface with lotus leaf effect has many practical and potential applications in different fields.Although attempts to produce artificial superhydrophobic films have always been intensively performed in recent years
however
a simple and economical procedure to massproduce superhydrophobic surfaces is still in nead.In this paper
a novel replicamolding method using CaCO3 particles as template
was developed to fabricate bionic superhydrophobic polymer films.Briefly
CaCO3 particle suspension was first cast onto a glass substrate and then was dried towards forming a thin layer of particles.Then linear lowdensity polyethylene (LLDPE) was thermally pressed onto such a CaCO3 particles template.After being cooled
peeled off from the substrate and rinsed with flowing water
the LLDPE film with superhydrophilic surface was obtained.Then this superhydrophilic LLDPE surface was further etched in 20 wt% HCl solution for 10 min.After washing and drying
the LLDPE film with superhydrophobic surface was obtained
with water contact angle (WCA) up to (152.7±0.8)° and sliding angle less than 3°.Moreover
such superhydrophobicity was confirmed stable under water jet at high pressure and durable in warm water (lower than 50℃).SEM imaging showed that such superhydrophobicity was attributed to the typical micro-and nanometer scale porous surface structure.Other types of polymers such as LDPE
HDPE
polypropylene (PP)
polystyrene (PS) and polyurethane (PU) had also been replica molded using the similar process.All formed superhydrophobic and micro-and nano-porous surfaces except for PU
which only formed normal hydrophobic and microporous surface.Because CaCO3 microparticle is low-cost and can be easily covered onto the surface of the rolling mold
which is generally used in flow-casting process in manufacturing plastic films
superhydrophobic plastic films could be thus produced cost-effectively in large scale.