A Modified Micromolding Method for Sub‐100‐nm Direct Patterning of Pd Nanowires

Abstract

An unconventional modification of a poly(dimethylsiloxane) stamp hosting microchannels leads to the formation of nanochannels entrapping a precursor, which metallizes into sub‐100‐nm Pd nanowires under the molding conditions (see image). This is a single‐step direct‐patterning technique termed nanoentrapment molding.

Micro- and nanostripes of self-assembled Au nanocrystal superlattices by direct micromolding

“…As seen in the magnified image of one stripe, the sizes of the crystal vary (5-10 nm) but the nanocrystals are tightly packed into thread-like features. The formation of such narrow stripe features from microchannels is typical of the nanoentrapment process [49]. In conformity with the nanochannel formation, we see pairs of parallel stripes ~70 nm wide with internal separation of ~430 nm and a distance of ~990 nm between each pair (see Fig.…”

“…One may manipulate the fluid flow conditions inside the microchannels to achieve narrow feature sizes. Earlier, we have shown that starting with a stamp with nearly micron sized features, it is possible to directly imprint truly nanometric line patterns [49]. We term this process nanoentrapment molding, since under the pressure and heat treatment applied, the precursor is only deposited at the edges of the relief features.…”

Self-modulating polymer resist patterns in pressure-assisted capillary force lithography

“…For example, if the polymer thickness is larger than $0.56 lm, a residual layer remains after the process (see Supplementary information, S1a); if the polymer thickness is less than $0.18 lm, on the other hand, the roof of the mold touches the substrate, so that there would be no polymer layer remaining in the center of the cavity, as judged by two broken lines accumulated at the mold edges (see Supplementary information, S1b). In fact, this edge capillary rise has been utilized to reduce pattern size from the original master [20,21].…”

“…For example, Rhee et al used PDMS molds for realizing a reversely tapered structure by the elasticity-based mold fabrication (EMOF) [18] and Huh et al fabricated a nanochannel with reversible functionality by PDMS wrinkling [19]. Also, the PDMS roof collapse by overpressure has been exploited in the contact printing of features with reduced size [20] as well as in the capillary filling of sub-100-nm Pd nanowires into nanocavities [21].…”

A Simple Water‐Based Synthesis of Au Nanoparticle/PDMS Composites for Water Purification and Targeted Drug Release

“…[12] It has applications in many fields including microfluidics, [13] biomedical implants and devices, [14,15] chemical separation, [16] and microstructure fabrication. [17,18] Another important feature of PDMS is its solid solution nature and resulting high absorption ability for a range of aromatic materials. [19] The literature on Au nanoparticles is rich and abound with examples relating interesting electronic and optical properties to potential applications.…”