High-Resolution Direct Patterning of Gold Nanoparticles by the Microfluidic Molding Process

Abstract

A novel microfluidic molding process was used to form microscale features of gold nanoparticles on polyimide, glass, and silicon substrates. This technique uses permeation pumping to pattern and concentrate a nanoparticle ink inside microfluidic channels created in a porous polymer template in contact with a substrate. The nanoparticle ink is self-concentrated in the microchannels, resulting in dense, close-packed nanoparticle features. The method allows for better control over the structure of printed features at a resolution that is comparable to inkjet printing, and is purely additive with no residual layers or etching required. The process uses low temperatures and pressures and takes place in an ambient environment. After patterning, the gold nanoparticles were sintered into continuous and conductive gold traces.

Self-powered integrated microfluidic point-of-care low-cost enabling (SIMPLE) chip

“…In addition, it is difficult to increase concentration while keeping small footprints because multiple print runs are necessary. Other printing methods, such as capillary printing ( 8 ), microfluidic networks ( 9 ), evaporation ( 10 ), and degas-based printing ( 11 ), usually create continuous line-shaped patterns rather than dot-shaped patterns. There is a need for a method that can concentrate the reagents into highly defined dot-shaped footprints that fit in the microwells so that multiplexed reactions can commence directly in the microwells without cross-contamination.…”

Inducing compressive residual stress in microscale print-lines for flexible electronics

“…Control over the height of features can be corrupted by capillary action between the mold and the drying ink, in particular along the length of longer features. Thus, as a possible alternative to nanoimprint lithography, nanoparticle self-assembly methods, based on capillary filling of photoresist templates have been proposed (Demko, Cheng, & Pisano, 2010), and appear to be promising. It is important to note that many of the processes involve evaporative cooling, and require a simultaneous heat and mass transfer analysis.…”

Rapid Computation of Statistically Stable Particle/Feature Ratios for Consistent Substrate Stresses in Printed Flexible Electronics

“…For an early history of the printed electronics field, see Gamota et al [1], Applications include, for example, optical coatings and photonics [2], MEMS applications [3,4], and biomedical devices [5]. There have been many proposed processing techniques, and we refer the reader to Sirringhaus et al [6], Wang et al [7], Huang et al [8], Choi et al [9][10][11][12], Demko et al [13,14], and Fathi et al [15] for details.…”