Self-Stratifying Coating with Robust and Durable Superhydrophobic Underlayer Constructed by Amphiphilic Janus Nanoparticles

Abstract

The multifunctional gradient self-stratifying coating (SSC) is attractive in many applications, but the robustness and durability of the functionalities still remains challenging. Here, a water-based SSC composed of amphiphilic Janus nanoparticles (JNPs) and binder latex is constructed by an extremely simple one-step drying method. The surface-partitioned “soft–hard” JNPs are specially designed and synthesized, in which the hard side of the JNPs (fluorosilane modified silica) imparts hydrophobicity and mechanical strength to the SSC, and the soft side contributes to the uniform dispersion of the hydrophobic JNPs in a water-based mixture and strong adhesion of JNPs to binder. Coatings with various microstructures and properties could be obtained simply by adjusting the binder solid content. Among them, the desirable SSC with a binder-rich upper layer and a JNPs-rich lower layer possesses a smooth surface and a superhydrophobic underlayer. The superhydrophobic underlayer of this SSC exhibits durable superhydrophobicity after 300 abrasion cycles and remarkable water repellency after heavy pull-off as well as good flexibility (film-forming). Our designs could provide new strategies for the development of low-cost and high-performance water-based SSC.

Soft‐Hard Janus Nanoparticles Triggered Hierarchical Conductors with Large Stretchability, High Sensitivity, and Superior Mechanical Properties

“…Janus particles, a surface partitioned material, were proposed by P.-G. de Gennes in his Noble Prize address to depict a special class of colloidal particles with distinct chemical components (e.g., inorganic and organic), physical properties (e.g., soft and hard), or functionality (e.g., hydrophilicity and hydrophobicity) on their two hemispheres. [39,40] The opposite composition or properties on the surface of one object make it show attractive attention in the solid emulsifier, [41,42] functional coating, [43][44][45] compatibilizer for polymer blends, [46][47][48] colloidal motor, [49,50] etc. This Janus particle with bicomponent or biphasic property is expected to address the dilemma between mechanical properties and conductivity of composite, achieving the largely stretchable conductors by promoting the dynamic reconstruction of the conductive pathway.…”

Quantitative imaging methods for heterogeneous multi-component films

“…The drying of colloidal dispersions occurs in a wide range of applications, including paints, glues, inks, and cosmetics. Depending on the components and the application, the final dry film can impart a diverse range of functionalities to the surface, such as adhesiveness, 1 colour, 2 antimicrobial qualities, 3 mechanical robustness, 4 electrical conductivity, 5 water barrier properties, 6 corrosion resistance, and more. These features strongly depend on the spatial distribution of the ingredients, which should in some cases be uniform, yet in other cases exhibit preferential partitioning to the top or to the substrate.…”