Large-Area Accurate Position Registry of Microparticles on Flexible, Stretchable Substrates Using Elastomer Templates

Abstract

This work introduces a robust means for excellent position registry of microparticles via a forced assembly technique on flexible or stretchable substrates. It is based on the dry powder rubbing process which allows assembly of a microparticle monolayer in a short time without requiring any solvent or thermal treatment. Elastic physical templates are used as substrates for the forced assembly in this study. Since the elastic templates can reduce the stress accumulation between the closely packed particles, they can minimize the defect formation in the particle assembly in large areas. The method can be used with powders comprising irregularly shaped particles with a relatively large size distribution that cannot be periodically ordered by conventional self-assembly. Furthermore, a non-closely packed particle array can be fabricated readily in large area, which is highly desirable for practical uses of the particle monolayers. The particle monolayers formed on the elastomer templates can be transferred to surfaces coated with thermoplastic block copolymers. Once transferred, the particle monolayers are flexible and stretchable over their entire surface. This work uses the particle monolayers on a large-area flexible substrate as photomasks to produce various photoresist patterns.

Highly Stretchable and Wearable Thermotherapy Pad with Micropatterned Thermochromic Display Based on Ag Nanowire–Single‐Walled Carbon Nanotube Composite

“…To realize the RGB sub‐pixelation on the thermochromic display, the RGB TMPs were arrayed into the dot‐patterned PDMS stencil using soft lithography and a unidirectional rubbing technique . To overcome the deterioration in the display resolution caused by mechanical deformation, the micropatterned PDMS stencil with an island structure was introduced to relieve the strain by dispersing into the nonpatterned sites . A schematic illustration of the soft lithography process for the PDMS stencil is shown in Figure S9 (Supporting Information) and the detailed fabrication process is given in the Experimental Section.…”

E‐Skin Tactile Sensor Matrix Pixelated by Position‐Registered Conductive Microparticles Creating Pressure‐Sensitive Selectors

“…We modified the previously developed dry rubbing process to improve the positional accuracy and gain more freedom in pattern design. UV‐cured gel patterns were used as a physicochemical template on which the MPs were rubbed to be selectively located.…”

“…The assembly process is shown in Movie S1 (Supporting Information). The physical template used in our previous study has concave structures that are not selectively adhesive to the MPs, whereas the physicochemical template has the concave structures with selective chemical adhesion with the MPs. In this study, the semi‐cured soft gel in the grooves provided large adhesion to the MPs selectively.…”

Continuous roll-to-roll patterning of three-dimensional periodic nanostructures

“…Another nanofabrication approach relies on the "bottomup" self-assembly of colloidal elements to build 2D or 3D structures [29][30][31][32][33][34][35] . For the assembly of a single layer or few layers on a planar surface 32,34,[36][37][38][39][40][41][42] , these colloids can be used as physical masks for deposition 43,44 or etching [45][46][47] processes. For 3D assembly, these methods can be employed to fabricate opal or inverse opaline structures 5,32 , hemispherical metal shells 48 , or hierarchical nanopore arrays 5,45,49,50 .…”

“…However, the self-assembly of colloidal crystals can only yield nanostructures with limited lattice geometry, such as opal/inverse opal or hexagonal close-packed arrays. The resulting assemblies are also typically qualitatively studied through visual observation or frequency analysis of the spectra [35][36][37][38][39][40][41]51 , which provides limited information regarding the average lattice spacing and relative assembly order. Therefore, precise quantitative metrology of the assembly yield rate over a large area is challenging.…”