IIT Ghy mimics nature to develop water repellent coating

Guwahati, March 19: An extremely water repelling polymeric coating has reportedly been synthesized by a team from the Indian Institute of Technology (IIT) Guwahati and experts are all excited about this. The Journal of Materials Chemistry A says the coating will make beaded droplets of water roll off just like the surface of a lotus leaf or will make water stick to the surface, just like a rose petal.

The synthetic material could reportedly provide a platform to design materials for widespread applications like self-cleaning, oil-water separation, water harvesting, guided water transfer, drug release, drug screening etc. This kind of coating is called super-hydrophobic which means extremely difficult to wet.

This coating can be spray-coated on various surfaces like glass, plastic, metal, wood and concrete, the surface can be of diverse chemical composition or texture whether smooth or rough surface, can be of different shapes, like plain sheet or complex shape such as shoes and can be of any size.

The team led by Dr U Manna from the IIT Ghy’s Department of Chemistry reportedly found the water-repelling property of the coating intact despite being subjected to severe physical and chemical abuse.

This coating was prepared by mixing a polymer- branched poly(ethyleneimine) and a reactive small molecule- dipentaerythritol penta-acrylate, in different alcoholic solvents- ethanol to pentanol and has diverse applications depending on whether it is made adhesive or non-adhesive.

By ‘modulating’ the functionality of the coating with small amine molecules, the coated surface was made to behave either as non-adhesive super-hydrophobic coating where water rolls off as in a lotus leaf or adhesive super-hydrophobic coating where the droplets stick to the surface like in the case of rose petals.

The coating being highly chemically reactive, it makes it possible to even post modify the coating to make it either adhesive or non-adhesive super-hydrophobic. Unlike in other cases, the reactants themselves get covalently cross-linked thus making the use of external binder or cross-linker for stability redundant.