Three steps to organic–inorganic hybrid films showing superhydrophilic properties

The concept of surface polymerisation to obtain dendritic functionalised surfaces is combined with the grafting of nanoparticles to realise hyperbranched functionalised PE surfaces for the control of wettability and surface adhesion. First, plasma induced polymerisation of acrylic acid allows highly reactive PE surfaces to be obtained. The further covalent grafting of amine functionalised silica nanoparticles (NPs) of 20 nm diameter was realised in one step with specific coupling agents for the creation of amide bonds between the NPs and the polyacrylic acid (pAA) surface. This reaction can be conducted in dichloromethane as well as in water depending on the coupling agents. This procedure afforded in three steps (plasma activation, polymerisation of acrylic acid and grafting of silica nanoparticles) highly functionalised hybrid organic–inorganic films. IR analysis as well as microscopic observations (AFM and SEM) and wettability measurements attest the PE surface modifications. Depending on the conditions used to link the NPs to the surface, superhydrophilic material can be reached.