FPP3D: Coupling frontal photopolymerisation and interfacial wrinkling for single shot 3D patterning

The solidification of polymeric materials by light exposure is a common approach in coatings and patterning technologies. Under specific conditions, a solidification front (defined by the interface between liquid and solid) is sharp and, driven by light, travels thereby invading the unpolymerised material. Such light-driven travelling wave polymerisation processes give rise to frontal photopolymerisation which is an attractive manufacturing tool for multi-level patterns and objects. It is thus desirable that the liquid-solid front is planar and smooth. However, interfacial "roughness" may occur at certain front velocities, light intensity, temperature, time and other manufacturing conditions. This project will investigate and control this "roughness" - caused by wrinkling, folding and creasing of the interface - to manufacture functional surfaces of high value. An experimental capability map and predictive computational tool will be established and validated and then applied to rapidly prototype exemplars of this novel manufacturing approach, including optically active materials with smooth 3D profiles.

Our project will provide academic and industrial opportunities that have the potential to impact positively our economy, people, knowledge and society. In terms of economic impact, our novel 3D photolithography approach has substantial potential in: Optics and Photonics manufacturing, to inexpensively rapidly prototype and fabricate customised optical components, including aspherical lenses, diffractive optical elements, arrays, optical fibre couplers; Coatings sector, via the ability to controllably and inexpensively pattern large areas down to sub-micron dimensions, and thus impart function to materials, including directional or tailored wetting/spreading, optical appearance (including refection and scattering), adhesion, and tactile properties; Maritime industries, as patterned surfaces affect drag and fouling, which can lower energy consumption; Bioengineering and medicine as patterned surfaces and scaffolds can affect cell proliferation, motility and even differentiation; General rapid prototyping industries, including for the fabrication of microreactors. The project will generate knowledge in developing and opening routes for polymer science, pattern formation, light manufacturing and an array of technology application areas. It will also develop mathematical and simulation tools to describe no-planar wave processes, including directional solidification. In terms of people, will also train highly skilled experimentalists and modellers with broad expertise in these areas and unique knowledge in frontal photopolymerisation, who will work closely with large research teams, including in our PE-CDT, BP-ICAM and programme grant members; resulting publications and presentations at conferences will affect a wide cross-section of researchers and industrialists. Finally, the project will deliver societal impact via: potentially bespoke consumer goods with advanced properties, including optical/photonic, sensorial, wetting/spreading, manufactured at low cost; sustainable manufacturing processes, rapid and low cost, allowing successive iterations and exploring a large parameter space for innovative patterning-based technologies; possible increased manufacturing capability and job creation; public and young people engagement activities, promoting the role of science and engineering in solving complex societal problems.