Nanoimprinted Polyethyleneimine: A Multimodal Template for Nanoparticle Assembly and Immobilization

• Published in: Advanced functional materials Vol. 19; no. 18; pp. 2937 - 2942
• Main Authors: Subramani, Chandramouleeswaran, Ofir, Yuval, Patra, Debabrata, Jordan, Brian J., Moran, Isaac W., Park, Myoung‐Hwan, Carter, Kenneth R., Rotello, Vincent M.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY‐VCH Verlag 23.09.2009
• Subjects: Heterogeneous assembly; Nanoimprint lithography; Nanoparticle immobilization
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.200900805

Polyethyleneimine (PEI) is used as a scaffold for integrated top‐down/bottom‐up fabrication. In this synergistic strategy, patterned PEI surfaces are created using thermal nanoimprint lithography (NIL) using a sacrificial polystyrene (PS) overlayer. These imprinted surfaces act as versatile templates for assembling nanoparticles and dyes, with the amine groups of the PEI enabling electrostatic assembly, carbodiimide coupling, and dithiocarbamate attachment to the nanoimprinted features. The efficient assembly of particles and dyes is confirmed through fluorescence and atomic force microscopy. In these studies the PS overlayer serves two roles. First, the PS layer protects the PEI surface during the plasma‐etch removal of the residual layer of the NIL process. Second, the PS overlayer serves as a mask, enabling sequential functionalization of the sides and the tops of the PEI features. Thermal nanoimprint lithography is used to pattern a polyethyleneimine functional polymer, allowing the formation of nano/micro templates for assembling nanoparticles/dyes via diverse chemical reactions, such as electrostatic self‐assembly, carbodiimide coupling, dithiocarbamate and thiourea conjugation. Geometrically assisted assembly of two materials is achieved by a combination of a polystyrene mask layer in a two step assembly process (see figure).