Hydrophobic layered double hydroxides (LDHs) based polymer composites

Abstract

Through intensive research and development, it has been established that hydrophobic coatings can impart several advantages to a variety of surfaces. Some advantages include decreased dirt retention, improved moisture and corrosion resistance and self-cleaning ability. It is known that surface roughness is one of the parameters that contributes to hydrophobicity. Many existing literatures focused on the use of silica particles and others as fillers in the development of hydrophobic polymer composite coatings. However, less attention was paid to using layered double hydroxides (LDHs) as fillers to develop such coatings.

In this project, hydrophobic LDHs based polymer composite coatings were prepared by using nickel cobalt layered double hydroxides (Ni-Co LDHs) as the fillers with hydrogenated styrene butadiene block copolymer (SEBS) as the polymeric matrix. The SEBS/Ni-Co LDHs coatings were prepared by solution casting. SEBS is a thermoplastic elastomer, which consists of rubbery elastomeric component and rigid component. The soft phase can be any typical elastomers such as polybutadiene while the hard phase can be polystyrene, urethane or poly(methyl methacrylate).

The hydrophobic performance of the SEBS/Ni-Co LDHs composite coatings was compared with pristine SEBS coating by contact angle measurements. Additionally, prepared coatings were characterized by surface roughness measurement, X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), pencil hardness test and peel test. The best hydrophobic performance was achieved when the mass ratio of SEBS to Ni-Co LDHs was 10:9. Furthermore, the morphology of the prepared coatings proves that the presence of Ni-Co LDHs in the SEBS matrix was responsible for the improved hydrophobicity.

Further research can be conducted to produce such coatings with better mechanical properties and improved transparency in order to widen its applicability to serve more purposes.