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Lecture Lifeng Chi

Rooster

WanneerWaar
11 april 2007 FWN-Building 5113.0202, Nijenborgh 4, 9747 AG, Groningen
Speaker:Prof. Dr. Lifeng Chi
Affiliation:Physikalisches Institut and Centre for Nanotechnology, Westfaelische Wilhelms-Universitaet, Muenster, Germany
Title:Self-organized surface patterning
Date:Wed Apr 11, 2007
Start:15.30
Location:FWN-Building 5113.0202
Host:Paul van Loosdrecht
Telephone:+31 50 363 8149

Abstract

Surface patterning is of great importance in modern science and technology. Patterning is usually achieved by top-down strategies, such as optical and e-beam lithography, soft-lithography, scanning probe lithography, and nanoimprint lithography. In contrast, the concepts of self-assembly and self-organization provide another interesting route toward the formation of patterned structures via a bottom-up approach. We demonstrate a bottom-up approach to form regular line patterns by transferring a Langmuir monolayer of L-a-dipalmitoyl-phosphatidycholine (DPPC) from air/water interface onto solid substrate. By adjusting the experimental conditions such surface density (surface pressure), transfer speed, temperature, humidity and molecular compositions we are able to control the periodicity of the line patterns and even create other types of patterns, e. rectangular lattice. This method provides an easy and fast route to get chemically patterned surfaces with different chemical activities over large areas. Structured surfaces of several cm2 can be easily produced with feather size down to 100 nm. The surface exhibits different surface free energies and chemical activities, which gives rise to anisotropic wetting phenomena thus allow a further parallel nanofabrication on large-areas. In addition, we found a way to use monolayers as a resist to anisotropically etch features in silicon with an aspect ratio of ~1 and an etch selectivity >100:1 (monolayer thickness:etch depth). Recently, we extended the concept to two-component systems to create luminescent stripe patterns as well as polymer stripe patterns with sub-micrometer widths over large areas by mixing dye molecules or polymer initiators with DPPC. Potential applications for e. guided cell growth is demonstrated.
Laatst gewijzigd:22 oktober 2012 14:30