Breath Figure in Reactive Vapor: A New Route to Nanopore Array

Abstract

A breath figure (BF)-inspired method for preparing ordered porous films has attracted more and more attention because of its simplicity, low cost, and easy implementation. However, it remains a challenge to use this method to fabricate nanoscale porous structures without designed polymer architecture and auxiliary. Herein, we first report a facile method to fabricate BF arrays with nanopores (nanoBFAs) in reactive vapor. Depending on the chemical reaction between the formic acid (FA) droplet template and the polyvinylpyridine (PVP) segments in copolymer, we successfully create nanoBFAs by casting a PVP-containing copolymer solution in CS in FA vapor. The condensed FA droplets can be instantly fixed by the PVP composition, and thus the growth and the aggregation of adjacent droplets are effectively restricted. Eventually, nanoBFAs are achieved in wide range solution concentration. In addition, binary porous structures with both nano- and microscale topology can be formed by using a FA/water mixed vapor with a one-step BF process. The produced nanoBFA films exhibit excellent antireflection performance with 0.5% reflectance, which is well-preserved even after hydrophobic treatment. This modified BF technique not only facilitates the elucidation of BFA formation mechanism but also opens a new way of fabricating nanoporous structures, which may have potential applications in electronic and optical devices.

Controlling the Self‐Assembly of Hierarchical PS‐b‐P4VP Structures Prepared by Dip‐Coating and Emulsion Breath Figure Techniques

“…For this purpose, as illustrated in Figure 1, BF films were created by dip‐coating a substrate into an emulsion consisting of water as the dispersed and PS‐ b ‐P4VP in chloroform as the continuous phase. PS‐ b ‐P4VP is an amphiphilic BCP, which has been extensively studied in the context of conventional BF fabrication [46–49] . The PS block is soluble in a wide range of organic solvents and the P4VP block can stabilize the water droplets during the BF formation by hydrophilic interactions.…”

“…PS-b-P4VP is an amphiphilic BCP, which has been extensively studied in the context of conventional BF fabrication. [46][47][48][49] The PS block is soluble in a wide range of organic solvents and the P4VP block can stabilize the water droplets during the BF formation by hydrophilic interactions. However, in our case, a stable emulsion could not be achieved solely by the P4VP block, indicated by phase separation between water and chloroform, resulting in a non-continuous BF film (Figure S2a).…”

Decoration of Material Surfaces with Complex Physicochemical Signals for Biointerface Applications

“…The breath figure method is considered as the self-assembled water droplets (or reactive vapor) on the surface of the polymer solution in a humid environment. The water droplet is the template during the solvent drying process, which leads to a hexagonal array of droplet-shaped holes on the substrate (Figure I). , …”

“…The water droplet is the template during the solvent drying process, which leads to a hexagonal array of droplet-shaped holes on the substrate (Figure 5I). 108,110 For example, Shebi and Lisa utilized polylactic acid (PLA) and rutile titanium dioxide (TiO 2 ) nanoparticles to generate porous thin films using this technique. The film has lightactivated bactericidal properties toward S. aureus because of the doped TiO 2 particles as well as good biocompatibility toward L929 fibroblast cells.…”