Ultra-high ordered, centimeter scale preparation of microsphere Langmuir films

L. N. Deepak Kallepalli , C. Constantinescu , P. Delaporte (1) , O. Uteza (1) , D. Grojo (1)

1 LP3 - Laboratoire Lasers, Plasmas et Procédés photoniques

Controlling the preparation of nano/microsphere monolayers on large areas remains a difficult task but is crucial for several fabrication methods of highly-ordered periodic nanostructures. We demonstrate the preparation of ordered monolayers of few square centimeters with an extremely high coverage ratio (>98%) by implementing a modified protocol (MP) Langmuir Blodgett (LB) technique. We use octadecyl type hydrocarbon (0 8) functionalized spherical particles (polystyrene and silica) with diameters in the range 1-5 mu m, and a selected mixture of solvents for accurate control of the surface tension and particles mobility at the water surface. This leads to a delicate growth of crystal-like monolayers which are subsequently transferred to glass or silicon substrates. While operating the Langmuir-Blodgett trough, a key enabling the quality enhancement resides not only on surface tension measurements but also on simple visual inspections of the water surface supporting the monolayer. The protocol yields a strong reduction of sensitivity to thermodynamical and mechanical disturbances leading to a robust method that could be automated by adding a feedback on the operated system based real-time image processing. A simple analytical approach is used to explain why this MP-LB technique is more appropriate in growing micrometric-sized objects in comparison to standard protocols optimized for the preparation of molecular films. (C) 2015 Elsevier Inc. All rights reserved.

Domaines: Optique / photonique

L. N. Deepak Kallepalli, C. Constantinescu, P. Delaporte, O. Uteza, D. Grojo. Ultra-high ordered, centimeter scale preparation of microsphere Langmuir films. Journal of Colloid and Interface Science, 2015, 446, pp.237-243. ⟨10.1016/j.jcis.2015.01.047⟩. ⟨hal-01418527⟩