Long Jiao,Dingqiang Tan,Yanjun Hu,Yijing Yang,Qianqian Guo,Nan Zhou,Huaping Wu,Chen Chen,Xingang Zhao,Guohua Hu
The droplet lossless directional motion control on slippery surfaces holds immense promise for applications in microfluidic chips, hazardous substance detection, chemical dispensing, etc. However, a significant challenge in this domain lies in efficiently developing soft, slippery surfaces with large-range anisotropic wettability and compatibility for curved scenarios. This study addressed this challenge through a quick 3D printing-assisted method to produce soft, ridged-slippery surfaces (SRSSs) as the droplet manipulation platform. The SRSSs demonstrated substantial anisotropic rolling resistances, measuring 116.9 μN in the perpendicular direction and 7.7 μN in the parallel direction, exhibiting a ratio of 15.2. Combining several extents of anisotropic wettability on a soft substrate could realize diverse reagent manipulation functions. Furthermore, these SRSSs showcased high compatibility with various droplet constituents, impressive liquid impact resistance, self-repair capability, and mechanical durability and thermal durability, ensuring exceptional applicability. As proofs of concept, the SRSSs were successfully applied in droplet control and classification for heavy metal ion detection, mechanical arm-based droplet grab and release, and cross-species transport, showcasing their remarkable versatility, compatibility, and practicality in advanced droplet microfluidic chips and water harvesting applications.
A series of poly(thioctic acid-catechol)s was prepared by supramolecular copolymerization of two low-molecular-weight monomers, thioctic acid (TA) and catechol (CA). The addition of a small amount of CA molecules significantly improved the adhesion ability of poly(TA) and transformed it into an applicable supramolecular polymer adhesive material. The robust adhesion of poly(TA-CA)s to soft surfaces was achieved by employing a hot-melt method. However, the supramolecular adhesion via the hot-melt method failed to perform in the presence of water. On-site supramolecular adhesion to wet and soft substrates was successfully realized through the solvent exchange behavior between water and the poly(TA-CA)s ethanol solution. Compared to the hot-melt method, the solvent exchange method displays various fascinating advantages and is suitable for adhesion conditions normally under the presence of water.