A shape memory porous sponge with tunability in both surface wettability and pore size for smart molecule release

Abstract

Recently, smart superwetting porous materials have aroused much attention, and it is well known that tunable surface wettability and pore structure/size are extremely important for their functions. However, only one factor can be regulated on existing materials, which significantly restricts their controllability, functions, and applications. A new material was prepared by electrodepositing a layer of polypyrrole on a shape memory sponge, on which switchable superhydrophobicity/superhydrophilicity and adjustable pore size within the range of about 28 nm to 895 µm can be observed. Through synergistically tuning the wettability and pore size, both ON/OFF water permeation and accurate flux can be obtained. Meanwhile, we also applied the sponge for molecule release, and diverse release manners with precise/smart controllability can be accomplished. This paper reports for the first time a smart material with controllability in both surface wetting and pore size, which provides a new strategy for the preparation of novel smart superwetting porous materials.

Designing Long-Term Cycle Life for a Lithium–Air Battery with a Modified Gas Diffusion Layer in Terms of the Moisture Intrusion and Electrolyte Volatilization

“…Researchers in the past used γ c as an extremely important empirical constant reflecting the wettability of solid surfaces with low surface energy. 45 Only the liquid with surface tension equal to or less than the surface γ c can spread on the solid surface, which means that the smaller the γ c value, the harder the surface is to wet. 46,47 In this experiment, PFDT was applied as a modifier to silver nanoparticles, which reduced the surface free energy of Ag and constructed nanostructures on the surface of the carbon paper.…”

“…Meanwhile, the terminal functional groups of the organic matter adsorbed on the surface will give new functions to the silver nanoparticles. Researchers in the past used γ c as an extremely important empirical constant reflecting the wettability of solid surfaces with low surface energy . Only the liquid with surface tension equal to or less than the surface γ c can spread on the solid surface, which means that the smaller the γ c value, the harder the surface is to wet. , …”

Precise Controlling of Friction and Adhesion on Reprogrammable Shape Memory Micropillars

“…Reprogrammed micro/nanostructures that can reversibly deform into multiple configurations as demanded have aroused enormous research interests for its broad application prospects in controllable friction, , tunable wettability, − optical engineering, − etc. , Up to date, various responsive materials that respond to different stimuli (e.g., light, heat, electricity, and magnets. , ) including elastic polydimethylsiloxane (PDMS) substrate, magnetic substance, , shape memory polymers (SMPs), − etc., have been adopted for realizing the controllable micro/nanostructure deformation. Among those, the SMPs possess particular advantages.…”

Controllable Droplet Sliding on a Smart Shape‐Memory Slippery Surface

“…[46,47] Based on the excellent shape memory effect of these materials, more convenient control of surface wettings and lots of new functions have been reported. [48][49][50][51][52][53][54][55][56][57] For example, through reversibly controlling microscale pillar shape between upright and collapsed states, Yang et al, realized the wetting transition and demonstrated droplet shedding on the superhydrophobic shape memory surface; [58] by decorating the shape memory arrays the pH-responsive capsules, Wu et al, reported the self-healing function on the superhydrophobic SMP surface; [59] based on similar shape memory effect, we also achieved several important results, such as precise wetting control, [48,51] controllable droplet storage, [60] capture/ release, [61] programmable droplet motion, [62,63] directional/ anti-directional droplet sliding, [64] and so on. [65][66][67] Nevertheless, almost all these works are concentrated on superhydrophobic surface, related wetting control on slippery surfaces are still extremely rare and only reported in recently.…”