ABSTRACTNovel surface engineering techniques of polymeric materials are essential to produce advanced topographies which could for example serve to modulate cell and tissue response in bio-materials. Direct Laser Interference Patterning (DLIP) permits the fabrication of repetitive arrays and microstructures by irradiation of the sample surface with coherent beams of light. Furthermore, the most important advantage of this method is that no additional process steps are required in comparison with other top-down or bottom-up techniques. In this study, we report a novel method for the advanced design of architectures in polymers using a single step process, as well as photo-activation of polymers with low absorption coefficient using a second polymer with relative high absorption coefficient. Previously calculated interference patterns using the well known interference theory could be directly produced on polymeric surface. Moreover, the cross-section of the structured polymers changes depending on the intensity of the laser beams, and photomachinability of polymers is highly influenced by laser wavelength. High absorbance of the polymeric materials at specific wavelengths allows the reduction of the laser intensity required to achieve a determined structure depth. For (60:40 %) polymethylmetacrylate/polystyrene copolymer substrate, different structures types were observed depending on the laser intensity including swelling and ablation of the material.
Bright betatron radiation from direct-laser-accelerated electrons at moderate relativistic laser intensity