Patterning of SiO2 nanoparticle–PMMA polymer composite microstructures based on soft lithographic techniques

Soft lithography and self-assembly provide powerful means of organizing colloidal solution of synthesized nanoparticles (NPs) for a wide variety of application. Pattern transfer of silicon dioxide (SiO2) nanoparticles–polymethylmethacylate (PMMA) nanocomposite was investigated using two such soft lithographic techniques, micro molding in capillaries (MIMIC) and micro transfer molding (μTM) using an elastomeric stamp in Polydimethyl siloxane (PDMS). Nanocomposite periodic arrays of 20 μm wide and 10 μm deep lines with 10 μm spacing were obtained over approximately 1 cm2 area on silicon substrates by μTM and MIMIC using a 3 wt.% monodisperse silica nanoparticles (∼338 ± 2 nm) in polymethyl methacrylate (PMMA) solution. In addition, free standing nanocomposite self-standing films of centimeter size were also manufactured by μTM. Single line of nanocomposite could also be obtained using MIMIC with a lower concentration of silica NPs (0.25 wt.%) in PMMA.