Superhydrophobic Polyimide Films with a Hierarchical Topography: Combined Replica Molding and Layer-by-Layer Assembly

Citations Over TimeTop 10% of 2008 papers

Abstract

Artificial superhydrophobic surfaces with a hierarchical topography were fabricated by using layer-by-layer assembly of polyelectrolytes and silica nanoparticles on microsphere-patterned polyimide precursor substrates followed with thermal and fluoroalkylsilane treatment. In this special hierarchical topography, micrometer-scale structures were provided by replica molding of polyamic acid using two-dimensional arrays of polystyrene latex spheres as templates, and nanosized silica particles were then assembled on these microspheres to construct finer structures at the nanoscale. Heat treatment was conducted to induce chemical cross-linking between polyelectrolytes and simultaneously convert polyamic acid to polyimide. After surface modification with fluoroalkylsilane, the as-prepared highly hydrophilic surface was endowed with superhydrophobicity due to the bioinspired combination of low surface energy materials and hierarchical surface structures. A superhydrophobic surface with a static water contact angle of 160 degrees and sliding angle of less than 10 degrees was obtained. Notably, the polyimide microspheres were integrated with the substrate and were mechanically stable. In addition, the chemical and mechanical stability of the polyelectrolyte/silica nanoparticle multilayers could be increased by heat-induced cross-linking between polyelectrolytes to form nylon-like films, as well as the formation of interfacial chemical bonds.

Related Papers

• → Nanoparticles in Polyelectrolyte Multilayer Layer-by-Layer (LbL) Films and Capsules—Key Enabling Components of Hybrid Coatings(2020)76 cited
• → Characterization of polystyrene surface by a modified two-liquid laser contact angle goniometry(1995)32 cited
• → Anomalous Polyimide Nanoparticles Prepared from Blending of Unlike Polymers(2009)5 cited
• → Contact Angles on Swollen Polymers: The Surface Energy of Crosslinked Polystyrene(1979)22 cited