Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/198531

Title

High-resolution surface chemical analysis of a trifunctional pattern made by sequential colloidal shadowing

Author(s)

Ogaki, Ryosuke;  Lyckegaard, Folmer;  Kingshott, Peter

Abstract

We present a new method for creating surface chemical patterns where three chemistries can be periodically arranged at alternate positions on a single substrate without the use of top-down approaches. High-resolution chemical imaging by time-of-flight secondary ion mass spectrometry (ToF-SIMS), with nanometer spatial resolution, is used to prove the success of the patterning and subsequent chemical modification steps. We use a combination of colloidal self-assembly, plasma etching, self-assembled monolayers (SAMs) and physical vapour deposition (PVD). The method utilizes a double colloid assembly process in which a first layer of close-packed colloids is created, followed by plasma etching, coating with gold and deposition of a first SAM layer. A second particle layer is deposited on top of the first layer masking the interstitial spaces containing the first SAM. A second gold layer is deposited followed by a second SAM. After particle removal the surface consists of the pattern containing two different SAMs and a SiO2 layer that can be readily functionalized with silanes. The possibility in the replacement of the two different thiols is investigated by X-ray photoelectron spectroscopy (XPS) and it was found that no replacement is taking place. ToF-SIMS imaging is used to show the periodicity of the chemical patterns by tracking unique fragment ions from the different surface regions. The patterning method is adaptable to create smaller or larger chemical patterns by appropriate choice of particle sizes. The patterns are useful for immobilizing biomolecules for cell studies or as multiplexed biosensors.Layer cake: Up to three chemistries can be periodically patterned at alternative positions on a single substrate by using a combination of colloidal assembly, self assembled monolayers and PVD (see picture). High-resolution imaging of the patterned surface is carried out by time of flight secondary ion mass spectrometry with submicron-sized patterned features.

Publication type

Journal article

Source

ChemPhysChem, Vol. 11, no. 17 (Dec 2010), pp. 3609-3616

Publication year

2010

FOR Code(s)

0306 Physical Chemistry (Incl. Structural)

Keyword(s)

Chemistry;  Colloidal assembly;  Colloids;  Gold;  Mass spectrometry;  Methodology;  Particle size;  Photoelectron spectroscopy;  Self-assembly;  Sulfhydryl compounds;  Surface analysis;  Surface properties;  Thiol derivative;  X-ray photoelectron spectroscopy

Publisher

Wiley

ISSN

1439-4235

Publisher URL

http://dx.doi.org/10.1002/cphc.201000737

Copyright

Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Peer reviewed