A Bioinspired, Highly Transparent Surface with Dry‐Style Antifogging, Antifrosting, Antifouling, and Moisture Self‐Cleaning Properties

Abstract

Transparent coatings with antireflection, antifogging, antifrosting, antifouling, and moisture self‐cleaning properties can dramatically improve the efficiency and convenience of optical elements and thus are highly desirable for practical applications. Here, it is demonstrated that a bionic nanocone surface (BNS) fabricated by a facile, low‐cost process consisting of template‐assisted prepolymer curing followed by surface modification can possess the multiple functions listed above. The polymer coating firmly adheres to a glass substrate due to bonding agents. After SiO2 nanoparticle deposition and low‐surface‐energy fluorosilane modification, the coating shows low microdroplet adhesion. As a result, the as‐prepared BNS exhibits a high transmittance when exposed to fog and good clarity even when the temperature decreases to −20 °C in a humid environment. Dipping the BNS into exemplified graphite powder has almost no influence on the transparency, and the BNS can realize self‐cleaning of moisture when the surface is covered with a thick layer of man‐made contaminants.

Large-Scale Formation of Fluorosurfactant-Doped Transparent Nanocomposite Films Showing Durable Antifogging, Oil-Repellent, and Self-healing Properties

“…Antifogging films have increasingly attracted much attention lately for a wide variety of practical applications including goggles, eyeglasses, windshields, mirrors, solar cells, medical/analytical instruments, and other industrial equipment. − To achieve such antifogging properties, preparation of superhydrophilic surfaces with static water contact angles (CAs, θ S ) of less than 5° is one of the most promising approach because on such surfaces, condensed water will rapidly form into a continuous transparent water-thin layer instead of formation of many small droplets, allowing for the reduction of visible light scattering. , Superhydrophilic surfaces have been widely prepared based on various techniques including layer-by-layer (LbL) deposition, − chemical vapor deposition (CVD), reactive ion/chemical etching, − postcalcination, − and so on, using silica (SiO 2 ) or UV-light-activated titanium dioxide (TiO 2 ) nanoparticles (NPs)/films, − ,, positively/negatively charged polyelectrolytes and/or NPs, − highly water-absorbent polymers, − composite hydrogels, − or polymer brushes. − Among these approaches, conventional methods for the preparation of superhydrophilic surfaces relying on textured/layered structures can be complicated, time-consuming, and not suitable for mass production. In addition, such man-made superhydrophilic surfaces typically lack self-healing abilities observed on living surfaces and so their functionalities are immediately and permanently lost once they are physically or chemically damaged.…”

Networked Zwitterionic Durable Antibacterial Surfaces

“…The surface hardness was measured by the pencil hardness test to confirm the surfaces for high-touch use. Concisely, the surfaces were scratched with pencils of various hardness ranging from 6H to 6B with a load of 750 g (ASTM D3363), − the test setup is shown in Figure S3. As a result, hardness ratings of 3H, HB, 2B, and 3B were obtained from AB-0, AB-47, AB-64, and AB-78 surfaces, respectively.…”

Coalescence-Induced Droplet Jumping

“…The pollutants attached to the surface layer can be quickly separated from the surface by the coalescence jumping of small droplets (Figure 12c1,c2). 88 Geyer et al coated the glass slide with siloxane nanowires in reducing the surface energy by fluorination to achieve selfcleaning. 89 Continuous outdoor experiments were carried out on polyester fabric with surface coating.…”