Light-induced charged slippery surfaces

Abstract

Slippery lubricant-infused porous (SLIPS) and superhydrophobic surfaces have emerged as promising interfacial materials for various applications such as self-cleaning, anti-icing, and antifouling. Paradoxically, the coverage/screening of lubricant layer on underlying rough matrix endows functionalities impossible on superhydrophobic surfaces; however, the inherent flexibility in programming droplet manipulation through tailoring structure or surface charge gradient in underlying matrix is compromised. Here, we develop a class of slippery material that harnesses the dual advantages of both solid and lubricant. This is achieved by rationally constructing a photothermal-responsive composite matrix with real-time light-induced surface charge regeneration capability, enabling photocontrol of droplets in various working scenarios. We demonstrate that this light-induced charged slippery surface (LICS) exerts photocontrol of droplets with fast speed, long distance, antigravity motion, and directionally collective motion. We further extend the LICS to biomedical domains, ranging from specific morphological hydrogel bead formation in an open environment to biological diagnosis and analysis in closed-channel microfluidics.

Morphing-to-Adhesion Polysaccharide Hydrogel for Adaptive Biointerfaces

“…The HABs have shown advantages over existing biointerfaces in superior bioactivity in directing cell functions, high-versatility geometrical adaptability for diverse biological tissues, particularly those of large surface curvatures, and excellent mechanical stability in high load-/shear-bearing physiologically mimicking environments. With synergistic adaptabilities in bioactivity, geometry, and mechanics, the HABs will provide new opportunities for biocompatible, conformal, and stable biointegration, which will also offer inspiration for developing adaptive biointerfaces to attain reliable functions for a variety of medical implants such as tissue engineering scaffolds and bioelectronics. − …”

Bioinspired superwetting materials for water manipulation

“…The controllable droplet movement was caused by the wettability gradient force due to the temperature gradient induced by asymmetric NIR loading (Figure 15b3). Wang et al 147 developed a light‐induced charged slippery surface (LICS) that held the dual advantages of both the solid substrate and the lubricant layer. The LICS was fabricated by three major components including microsized liquid metal particles for efficient photothermal conversion, copolymers with ferroelectric behavior, and surface microstructures for trapping the lubricant.…”

Electrification of water: From basics to applications

“…In detail, patterning light to achieve different conductivities of the surfaces can tailor different degrees of electrowetting for the water droplets on surfaces, and therefore, droplets could move from the light to the dark area (Figure 4g). 111,112 Different from optoelectrowetting, in the photopyroelectric effect, a light illumination‐induced electrostatic field is used to manipulate droplets 113–116 . As shown in Figure 4h, one single beam of light could trigger the heating of the irradiated spot on pyroelectric crystal substrates and therefore generate an electric field, which further exerts a dielectrophoretic force on the droplet.…”