Fabrication of multiscale structures on polymethylmethacrylate following pulsed CO2 laser irradiation

Different micro- and nanostructures are formed on the surface of the polymers following laser irradiation. The formation of these structures, which is dependent on the irradiation parameters and the material properties, affects the functionality and the efficiency of the polymers for a desired application. We investigate nano- and microstructure formation on the surface of polymethylmethacrylate polymer following pulsed CO2 laser irradiation at the wavelength of 9.55 μm in vacuum. Three different multiscale structures including nano- and microspheres, microholes, and ripples are formed on the surface after irradiation at various fluences below and above the ablation threshold. The possible mechanisms for the formation of these structures are explained. Melting, thermal waves, and internal stresses supposed to be the most important phenomena affect the shape and the size of the structures. The effect of irradiation on the UV–Vis spectra of the samples is also investigated.