title: Ultra-high ordered, centimeter scale preparation of microsphere Langmuir films.
abstract: 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 (C18) functionalized spherical particles (polystyrene and silica) with diameters in the range 1-5 μm, 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.
authors: Aix Marseille Université/CNRS, Laboratoire LP3 (UMR CNRS 7341), F-13288 Marseille, France. Electronic address: kallepalli@lp3.univ-mrs.fr.
authors: L N Deepak
authors: LN
authors: Kallepalli
authors: Aix Marseille Université/CNRS, Laboratoire LP3 (UMR CNRS 7341), F-13288 Marseille, France. Electronic address: constantinescu@lp3.univ-mrs.fr.
authors: C
authors: C
authors: Constantinescu
authors: Aix Marseille Université/CNRS, Laboratoire LP3 (UMR CNRS 7341), F-13288 Marseille, France.
authors: P
authors: P
authors: Delaporte
authors: Aix Marseille Université/CNRS, Laboratoire LP3 (UMR CNRS 7341), F-13288 Marseille, France.
authors: O
authors: O
authors: Utéza
authors: Aix Marseille Université/CNRS, Laboratoire LP3 (UMR CNRS 7341), F-13288 Marseille, France. Electronic address: grojo@lp3.univ-mrs.fr.
authors: D
authors: D
authors: Grojo
keywords: Langmuir–Blodgett; Microspheres; Monolayer; Photonics; Polystyrene; Silica