Introduction
Undesirable interfacial adhesion causes numerous technical issues that can impact various fields. A wide range of advanced anti-adhesion materials capable of repelling both water and oils have been developed to address these challenges, and they are described as anti-adhesion,1 non-stick,2self-cleaning,3 antifouling,4anti-smudge,5 anti-graffiti,6superwettability,7 superoleophobic,8superamphiphobic,9 or slippery liquid-infused porous surfaces (SLIPS).10 The common purpose of these materials is to minimize the interfacial wetting behavior and intermolecular forces between liquids and solid surfaces, which is achieved via the construction of micro/nanomorphologies or the manipulation of low-surface-energy molecules.
Micro/nanoscale roughened textures and re-entrant curvatures, which are generally regarded as lotus bioinspired structures, can enhance the liquid repellency of amphiphobic materials and render them superamphiphobic due to the presence of air pockets, exhibiting contact angles (CAs) greater than 150° and sliding angles (SAs) below 10°.11,12 Despite decades of intense research in this area, the applicability of these intricate micro/nanoscale surfaces has often been limited by their poor wear resistance, opacity, and the need for complex manufacturing processes.13,14
Flat surfaces comprised of molecules with weak intermolecular forces, including hydrogen bonds, electrostatic interactions, and van der Waals interactions, can also exhibit anti-adhesion performance, such as the repellency against water and cooking oil that is exhibited by polytetrafluoroethylene (PTFE, Teflon). It is noteworthy that the dynamics or rotation mobility of liquid molecules would greatly enhance the anti-adhesion performance. For example, the anti-adhesion function of solid Teflon would fail during contact with objects that exhibit strong multivalent hydrogen bonding such as crude oil, blood, and 2-amino-4-hydroxy-6-methylpyrimidine (UPy) modified hydrogels.1,15 In contrast, anti-adhesion behavior against these objects could be achieved by using a perfluorinated polyether (PFPE) lubricating film (with CAs of less than 120° and SAs below 10°).10 Unfortunately, it is a challenge to convert lubricating molecules into materials or incorporate them onto surfaces. The use of chemically modified monolayers,16,17 slippery liquid-infused porous surfaces (SLIPS),4,18 heating or UV-triggered polymer matrices,19,20 have been reported to achieve this so far, but these strategies plagued with the requirement of complex processes and extra equipment that restrict their on-site application onto structures with large surface areas.
Herein, we report a novel large-area and flat anti-adhesion coating with a lubricating surface that can be formed spontaneously at room temperature, thus it could be readily applied on-site via industrially-viable spray-, dip-, or paint-coating techniques onto various objects. The silicon-based and solvent-free precursor system also offers various attractive features, such as low cost, environmental friendliness, and biocompatibility, thus further enhancing the applicability of these anti-adhesion coatings.