Hexagonally close packed Langmuir-Blodgett films from monodispersed silica nanoparticles

This report demonstrates a novel procedure to produce hexagonally close packed nanoparticle film using the Langmuir-Blodgett (LB) technique. The LB technique has advantages over previously reported techniques, such as high reproducibility, formation of large area films with low-cost capable of producing a large number of hexagonally close packed nanoparticle films at a single process. In this method, a monolayer of mono-dispersed silica nanoparticles was spread on the surface of water and then transferred it onto a gold sputtered glass substrate or silicon wafer. The silica particles used for fabrication of LB films were synthesized by the modified Stöber method. In present work, we synthesized 300 +/- 5 nm sized silica particles. A large area of hexagonally close packed nanoparticle films fabricated by the LB technique was confirmed by AFM and FE-SEM. Furthermore, we demonstrate fabrication of over 34 hexagonally close packed nanoparticle LB films on glass substrates with area of 18 x 18 mm2 from a single process.