Tunable Colloidal Crystalline Patterns on Flat and Periodically Micropatterned Surfaces as Antireflective Layers and Printable–Erasable Substrates

Abstract

dip-pen lithography, [5] block copolymerbased patterning, [6] ink-jet printing, [7] and other techniques [8] have been used for different purposes and material types. Much attention has also been paid to 2D colloidal crystalline patterns, [9][10][11] which are useful in structure development and optical applications. Colloidal crystalline patterns are usually close-packed structures fabricated through Langmuir-Blodgett processes, [12,13] dip coating, [14,15] spin-coating, [16,17] electrodeposition, [18] floating and lift-up, [19,20] and other techniques. [21] Nonclose-packed structures can be achieved by etching the close-packed crystal patterns with plasma, [14,15,17,[22][23][24][25][26] ion beams, [13,[27][28][29] and electron beams. [30] Particle spacing can be controlled by the etching time. For inorganic corepolymer shell colloids, a thermal combustion method has been used to fabricate nonclose-packed inorganic colloidal patterns. [16,18] In some cases, nonclose-packed colloidal arrays may be achieved by deposition of core-shell and hydrogel colloids onto flat substrates in solutions and subsequent air-drying, [31,32] but spaces among the colloids are micrometer scale and the degree of crystalline order is low. Meanwhile, close-packed colloidal crystals can transform into nonclose-packed crystal patterns by stretching or swelling poly(dimethyl siloxane) (PDMS) substrates. [33][34][35] To fix the prepatterned colloidal arrays, the substrates should remain either stretched or swelled under certain conditions, and the pattern should be further transferred onto other substrates. Such a prepattern and transfer method could be advantageous to avoid damage to organic and polymer substrates caused by etching or thermal treatment. Nevertheless, there is a continual demand to develop a simpler method for nonclose-packed crystalline patterns without etching/combustion or transferring prepatterned colloids on substrates regardless of material types and surface structures of substrates. Additionally, it remains a challenge to effectively manipulate the structures of colloidal crystal monolayers, e.g., the size and morphologies of the colloidal particles. At the same time, a versatile method is also required to cover the fabrication of an ordered array of hybrid colloids comprising inorganic and organic particles. 2D nonclose-packed colloidal crystal patterns have received considerable attention in various fields, but it remains a challenge to fabricate patterns and manipulate their geometries regardless of substrate types and structures. Herein, a simple approach is developed for producing nonclose-packed hydrogel colloidal crystalline patterns on flat and periodically micropatterned substrates by exposing close-packed colloidal crystal monolayers to salt aqueous solutions. The patterns are achievable on flat surfaces like silicon, glass, graphene, poly(ethylene terephthalate), and poly(dimethyl siloxane) surfaces. Hydrogel colloidal spheres can deform into disk-like or hemispherical particles on different material subst...

Reaction-Based Scalable Inorganic Patterning on Rigid and Soft Substrates for Photovoltaic Roofs with Minimal Optical Loss and Sustainable Sunlight-Driven-Cleaning Windows

“…Details regarding the materials used in this experiment are provided in the Supporting Information. The building block colloids for forming a colloidal monolayer nanosheet were synthesized by modifying the method reported in the previous literature, 70 and the method is described in the Supporting Information. The colloidal nanosheets were fabricated on substrates by modifying the method reported in the previous literature, 54 and the method is also described in the Supporting Information.…”

“…The colloidal nanosheet coated on both side of a glass substrate was prepared by modifying a procedure in the literature. 70 For the preparation of a reaction solution, 50 μL of VTMS was hydrolyzed in 3 mL of deionized water for 10 min. Then, 2 mL of the aqueous VTMS solution was mixed with 5.6 mL of deionized water and 3 mL of methanol.…”

Chemically Triggered Metamorphosis of Colloidal Bilayer Sheets into Nanomazes and Their Conversion into Silicon and Plasmonic Optical Nanomazes

“…Synthesis of Colloids: The colloids were synthesized by modifying the method from a literature. [22] 1.5 g of N-isopropylacrylamide and 0.08 g of N,N′-methylene bis(acrylamide) were dissolved in 100 mL deionized water. The aqueous mixture attained equilibrium at 70 °C.…”

“…Closely packed monolayers can be converted into non-close-packed colloidal patterns through etching, solution treatments, and modulation of substrates. [12][13][14][15][16][17][18][19][20][21][22][23][24] The closely packed colloidal…”