Stable Wettability Control of Nanoporous Microstructures by iCVD Coating of Carbon Nanotubes

• Main Authors: Annavarapu, Rama Kishore (Author), Sojoudi, Hossein (Contributor), Kim, Sanha (Contributor), Zhao, Hangbo (Contributor), Mariappan, Dhanushkodi Durai (Contributor), Hart, Anastasios John (Contributor), McKinley, Gareth H (Contributor), Gleason, Karen K (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Chemical Engineering (Contributor), Massachusetts Institute of Technology. Department of Mechanical Engineering (Contributor), Massachusetts Institute of Technology. Department of Urban Studies and Planning (Contributor)
• Format: Article
• Language: English
• Published: American Chemical Society (ACS), 2018-12-03T14:57:22Z.
• Subjects: Article
• Online Access: Get fulltext

Scalable manufacturing of structured materials with engineered nanoporosity is critical for applications in energy storage devices (i.e., batteries and supercapacitors) and in the wettability control of surfaces (i.e., superhydrophobic and superomniphobic surfaces). Patterns formed in arrays of vertically aligned carbon nanotubes (VA-CNTs) have been extensively studied for these applications. However, the as-deposited features are often undesirably altered upon liquid infiltration and evaporation because of capillarity-driven aggregation of low density CNT forests. Here, it is shown that an ultrathin, conformal, and low-surface-energy layer of poly perfluorodecyl acrylate, poly(1H,1H,2H,2H-perfluorodecyl acrylate) (pPFDA), makes the VA-CNTs robust against surface-tension-driven aggregation and densification. This single vapor-deposition step allows the fidelity of the as-deposited VA-CNT patterns to be retained during wet processing, such as inking, and subsequent drying. It is demonstrated how to establish omniphobicity or liquid infiltration by controlling the surface morphology. Retaining a crust of entangled CNTs and pPFDA aggregates on top of the patterned VA-CNTs produces micropillars with re-entrant features that prevent the infiltration of low-surface-tension liquids and thus gives rise to stable omniphobicity. Plasma treatments before and after polymer deposition remove the crust of entangled CNTs and pPFDA aggregates and attach hydroxyl groups to the CNT tips, enabling liquid infiltration yet preventing densification of the highly porous CNTs. The latter observation demonstrates the protective character of the pPFDA coating with the potential application of these surfaces for direct contact printing of microelectronic features.
United States. Air Force. Office of Scientific Research (FA9550-11-1-0089)
Massachusetts Institute of Technology. Department of Chemical Engineering
University of Toledo
MIT-Chevron university partnership program
Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (Contract DAAD-19-02D-002)
National Science Foundation (U.S.) (award CMMI- 463181)
United States. Air Force. Office of Scientific Research
Skolkovo Foundation