Stimuli‐Responsive Liquid‐Crystal‐Infused Porous Surfaces for Manipulation of Underwater Gas Bubble Transport and Adhesion

Abstract

Biomimetic artificial surfaces that enable the manipulation of gas bubble mobility have been explored in a wide range of applications in nanomaterial synthesis, surface defouling, biomedical diagnostics, and therapeutics. Although many superhydrophobic surfaces and isotropic lubricant-infused porous surfaces have been developed to manipulate gas bubbles, the simultaneous control over the adhesion and transport of gas bubbles underwater remains a challenge. Thermotropic liquid crystals (LCs), a class of structured fluids, provide an opportunity to tune the behavior of gas bubbles through LC mesophase transitions using a variety of external stimuli. Using this central idea, we report the design and synthesis of liquid crystal-infused porous surfaces (LCIPS) and elucidate the effects of the LC mesophase on the transport and adhesion of gas bubbles on LCIPS immersed in water. We demonstrate that LCIPS are a promising class of surfaces with an unprecedented level of responsiveness and functionality, which enable the design of cyanobacteria-inspired object movement, smart catalysts, and bubble gating devices to sense and sort volatile organic compounds and control oxygen levels in biomimetic cell cultures.

Directional Transport of Underwater Bubbles on Solid Substrates: Principles and Applications

“…When the photostimulation is removed, the liquefied paraffin will be reconfigured to the solid phase, and the moving bubbles will be pinned (Figure 5c). Rather et al 42 fabricated a porous surface injected with thermotropic liquid crystals. The thermotropic liquid crystal molecules will selfassemble as a response to the temperature further resulting in a large change in surface wettability (Figure 5d).…”

“…The porous surface injected with the thermotropic liquid crystal made by Rather et al 42 can be used to detect and distinguish between pure bubbles and bubbles contaminated by volatile organic compounds. When pure bubbles are introduced from the inlet, the bubbles will not adhere to the substrate and will be directly released from compartment 1.…”

“…It can realize the remote and accurate manipulation of the object via the control of the bubble. The porous surface injected with the thermotropic liquid crystal made by Rather et al 42 has a greatly increased surface adhesion in volatile organic compounds. Therefore, bubbles can adhere to the substrate, and large bubbles can drive the light substrate to float by buoyancy (Figure 17a).…”

Fluid manipulationviamultifunctional lubricant infused slippery surfaces: principle, design and applications

“…92 (b) Thermally responsive SLIPSs prepared with thermally sensitive liquid crystals. 95 (c) SLIPSs with an asymmetric structure that deforms the bubble to generate a driving force for the directional motion of the bubble. 45 (d) Piecewise stitching of SLIPS tracks enables in situ bubble generation, capture and transport processes.…”

“…9b) by introducing thermotropic liquid crystals into this SLIPS. 95 Heng et al developed an amphibious slippery gel surface on which magnetically controlled motion of air and air bubbles was achieved. Magnetically controlled motion of air bubbles underwater was realized.…”