Abstract

Hybrid nano-devices are attractive systems, which combine the performance of hard-condensed materials with the versatility and flexibility afforded by soft-condensed functional materials. Instances of such systems are silicon-based nano-transistors, with organic elements introduced at specific locations to bring a new function such as bio-sensing, catalysis, chemical gating or even motion control; or organic channel nano-transistors wherein a polymer nano-wire serves to control charge transport between source and drain; or hybrid storage surfaces, where a hard patterned substrate hosts a grid of stimuli-responsive molecules.

The possibility to develop such hybrid nano-devices critically rests on our ability to assemble organic (macro-)molecules in nano-objects of controlled size, at specific locations on a substrate, with preferably some degree of control being achievable on the orientation of the molecules. Different ways can be used to reach these goals, from the relatively unsophisticated but sturdy lift-off methods used in classical semi-conductor technology, to the more demanding and error-prone self-assembly methods. In this lecture, we review a series of methods recently developed in our group to design nano-structured functional organic surfaces, which combine electron-beam [1] or nano-imprint lithography [2] with a variety of (self-)assembly processes such as crystallization [2,3], (layer-by-layer) adsorption [4-6], grafting to [7], grafting from, and dewetting [8]. These different methods will be described, and the principles governing the tuning of the physical parameters to control assembly will be discussed. Simple systems wherein chromophores or conjugated polymers provide an optical or electrical function will be presented and discussed. If time permits, first attempts towards controlling thermal responsivity at the nanoscale, the topic of my current sabbatical in Cambridge, will be briefly introduced.

References:

[1] ‘Binary Nano-patterned Surfaces Prepared from Silane Monolayers’, A. Pallandre, K. Glinel, A. M. Jonas, B. Nysten, Nano Letters 2004, 4, 365.

[2] ‘Nanoscale Control of Polymer Crystallization by Nanoimprint Lithography’, Z. Hu, G. G. Baralia, V. Bayot, J.-F. Gohy, and A. M. Jonas, Nano Letters 2005, 5, 1738.

[3] ‘Nano-Templated Crystallization of Organic Molecules’, J. Plain, A. Pallandre, B. Nysten, A. M. Jonas, Small 2006, 2, 892.

[4] ‘Tuning the Orientation of an Antigen by Adsorption onto Nanostriped Templates’, A. Pallandre, B. De Meersman, F. Blondeau, B. Nysten, A. M. Jonas, J. Am. Chem. Soc. 2005, 127, 4320.

[5] ‘Alignment and Assembly of Adsorbed Collagen Molecules Induced by Anisotropic Chemical Nanopatterns’, F. A. Denis, A. Pallandre, B. Nysten, A. M. Jonas, C. C. Dupont-Gillain, Small 2005, 1, 984.

[6] ‘Nano-Confined Polyelectrolyte Multilayers’, A. Pallandre, A. Moussa, B. Nysten, A. M. Jonas Adv. Mater. 2006, 18, 481-486.

[7] ‘Nano-Patterned Photo-Active Surfaces’, N. Frederich, thesis, Université catholique de Louvain, December 2006.

[8] ‘Decoding Nano-Patterned Surfaces by Block Copolymer Dewetting’, G. G. Baralia, C. Filiâtre, B. Nysten, A. M. Jonas, submitted.