There are various strategies to assemble nanoparticles (NP) over short length scales, but the organised arrangement of NPs over a large area to modulate optical and electrical properties is still remaining a challenge. We have recently developed a new, fast one-step route to create a polymer coating with periodic topographic patterns repeating with characteristic lengths on the order of a millimetre. In this presentation, we will report how we have added Au NPs to an aqueous colloidal dispersion and transported them to targeted positions during the formation of a patterned coating. In this method, which is called infrared radiation-assisted evaporative lithography, a lateral flow of both polymer and Au NPs in an aqueous dispersion is created by differences in the evaporation rate across the wet film surface. A directed transport of the Au NPs in the horizontal direction is possible by this technique. Ring or flake-like assemblies of the AuNPs embedded within the polymer in periodic dome-like structures are created, and the arrangement is tuned through variation of the sizes of the polymer particles and the Au NPs. The extinction coefficient (� in units of mm-1) was determined by transmission spectroscopy as a function of the lateral position with a step size of 50 �m. Depending on the process parameters, � can be modulated between values of 3 and 14 mm-1. Patterns prepared with smaller polymer particles lead to a stronger modulation of � in the visible range, whereas stronger modulation in the IR-range was observed when larger polymer particles were used. The fundamental insights into controlling particle transport, which were acquired in this research, have applications in the creation of materials for SERS substrates and for coating photovoltaics.

Directed organization of gold nanoparticles in polymer coatings over large length scales through infrared-assisted evaporative lithography

245th National Meeting (2013)

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