Microcontact Printing of Uniform Nanoparticle Arrays

Abstract

Uniform, close-packed monolayer and bilayer arrays of alkanethiol-coated gold nanoparticles have been used as “ink” for microcontact printing (μCP) following the technique of Xia and Whitesides (see Xia, Y.; Whitesides, G. M. Polym. Mater. Sci. Eng. 1997, 77, 596). The process is accomplished in two steps. First, a uniform monolayer of the nanoparticles is self-assembled on a water surface and is transferred intact to a patterned poly(dimethylsiloxane) (PDMS) stamp pad by the Langmuir−Schaefer (LS) method. In the case of multilayer printing, this “inking” step is repeated as many times as desired. Because multilayer arrays are assembled on the stamp pad layer-by-layer, adjacent layers may be made up of the same or different particles. The nanoparticles are transferred to a solid substrate by conformal contact of the stamp pad and the substrate. The technique has been used to print patterned monolayer and bilayer arrays on both hydrophobic and hydrophilic substrates. The quality of the transferred arrays has been verified optically and by transmission electron microscopy (TEM). This new μCP technique should be applicable to any particles that can be spread as a monolayer on a water surface and promises to be useful for nanofabrication.

Methods of surface chemical patterning

“…За счет капиллярных взаимодействий штамп переносит раствор на обрабатываемую поверхность. В настоящее время микроконтакт-ная печать может быть использована для переноса практически любого материала: металлов [19], полимеров [20], биоматериала [21], различных наноструктур [22,23].…”

“…Nowadays microcontact printing can be applied to transfer almost any material, e.g. metals [19], polymers [20], biomolecules [21], different nanostructures [22,23].…”

Recent progress in direct patterning technologies based on nano-imprint lithography

“…Especially, organic solvent-based nanoparticle solutions have been utilized for useful processing in diverse applications. Various direct patterning processes such as micro-contact printing (μCP) [103][104][105], ink-jet printing [106][107][108] and screen printing [109][110][111] have been developed to fabricate nano-and micro-structures using nanoparticle solutions. However, these processes have limitations of resolution, throughput and cost efficiency for mass production of functional nano-structures.…”

Sub-Micrometer Patterning Using Soft Lithography

“…Finally, there are a number of demonstrations that involve colloidal particles as the ink. Patterns of ordered and dense films can be achieved when Langmuir-Blodgett films of nanoparticles are employed to ink the stamp [106,107]. Conversely, it is also possible to position individual nanoparticles on a substrate.…”