Nanoengineered transparent and environment friendly superoleophobic coatings

Lead Research Organisation: University College London
Department Name: Mechanical Engineering

Abstract

Transparent and oleophobic (oil repellent) coatings have plethora of applications such as hand held device displays (e.g. smartphones and pads), solar panels, windshields, household windows etc. Our aim is manufacture and test superoleophobic coatings with excellent optical transparency and robustness. This is in general much more challenging than superhydrophobic coatings because oils have a much lower surface tension and thus they 'wet' a surface more easily. Typically, chemical moieties e.g. low surface energy fluorinated groups, are used to achieve oleophobic character; however fluorinated compounds can show bio-persistent behaviour and are progressively being banned in the EU. Common scalable synthesis of superhydrophobic surfaces comprise of spray coatings polymer/nanoparticle dispersions, which produce undesirable volatile organic compounds (VOCs). The size of nanoparticles need to be controlled careful to achieve optical transparency. Here we will focus on realizing fluorine-free (super)oleophobic coatings, with controlled morphology, while simultaneously minimizing the use of organic solvents to reduce VOCs. This process will utilize a hydrophobic polydimethylsiloxane (PDMS), with metal oxide nanoparticles, such as silica, ceria and zinc oxide, with different sizes. A non-fluorinated silanes will help reduce the surface energy of the coatings- essential to get superoleophobic character. Crucially size and porosity of nanoparticles will be controlled to achieve simultaneous superoleophobicity and transparency.

Publications

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Janowicz NJ (2020) Fluorine-Free Transparent Superhydrophobic Nanocomposite Coatings from Mesoporous Silica. in Langmuir : the ACS journal of surfaces and colloids

Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/R512400/1 01/10/2017 31/03/2022
1917780 Studentship EP/R512400/1 25/09/2017 24/09/2021 Norbert Jaroslaw Janowicz
 
Description Manufacture of fluorine-free superhydrophobic coatings with good transparency is the main target of this work in order to develop an environment friendly coating formulation that benefits from the advantages of superhydrophobicity. We are using hybrid-polymer and nanoparticles nanocomposite and have a variety of different fabrication routes including but not limited to spray coating, spin coating and aerosol assisted chemical vapour deposition (AACVD). We have synthesised various functional mesoporous silica nanoparticles around 120 nm in size with pore diameter approximately 3 nm. We have also manipulated polydimethylsiloxane (PDMS) polymeric network with introduction of metal oxide species for enhanced coating properties such as its durability. Publication on combining the nanoparticles and hybrid-PDMS is now published in the Langmuir journal which compares two coating methods. Currently, we are also developing further modifications to coating composition to achieve superoleophobicity as well as enhanced durability and transparency through work on organic and inorganic crosslinkers for PDMS. The PhD student (Norbert Janowicz) is steadily progressing towards completing his PhD on time despite the Covid restrictions and limited laboratory access since the start of the pandemic.
Exploitation Route Project not yet completed. Further work will be conducted over the next months to further the research by the PhD student (Norbert Janowicz) to reach further outcomes as briefly outlined in the section above.
Sectors Chemicals,Manufacturing, including Industrial Biotechology