title: Asymmetric Superhydrophobic/Superhydrophilic Cotton Fabrics Designed by Spraying Polymer and Nanoparticles.
abstract: Inspired by the special wettability of certain natural life forms, such as the high water repellency of lotus leaves, many researchers have attempted to impart superhydrophobic properties to fabrics in academic and industrial contexts. Recently, a new switching system of wettability has inspired a strong demand for advanced coatings, even though their fabrication remains complex and costly. Here, cotton fabrics with asymmetric wettability (one face with natural superhydrophilicity and one face with superhydrophobicity) were fabricated by one-step spraying of a mixture of biocompatible commercial materials, hydrophobic SiO2 nanoparticles and ethyl-α-cyanoacrylate superglue. Our approach involves controlling the permeation of the fabric coatings by changing the distance between the fabric and the sprayer, to make one side superhydrophobic and the other side naturally superhydrophilic. As a result, the superhydrophobic side, with its high mechanical durability, exhibited a water contact angle of 154° and sliding angle of 16°, which meets the requirement for self-cleaning ability of surfaces. The opposite side exhibited high water absorption ability owing to the natural superhydrophilic property of the fabric. In addition, the designed cotton fabrics had blood absorption and clotting abilities on the superhydrophilic side, while the superhydrophobic side prevented water and blood permeation without losing the natural breathability of the cotton. These functions may be useful in the design of multifunctional fabrics for medical applications.
authors.affiliation: Center for Material Design Science, School of Integrated Design Engineering, Graduate School of Science and Technology, Keio University , 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan.
authors.forename: Kaichi
authors.initials: K
authors.lastname: Sasaki
authors.affiliation: Center for Material Design Science, School of Integrated Design Engineering, Graduate School of Science and Technology, Keio University , 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Tenjimbayashi
authors.affiliation: Center for Material Design Science, School of Integrated Design Engineering, Graduate School of Science and Technology, Keio University , 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan.
authors.forename: Kengo
authors.initials: K
authors.lastname: Manabe
authors.affiliation: Center for Material Design Science, School of Integrated Design Engineering, Graduate School of Science and Technology, Keio University , 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan.
authors.forename: Seimei
authors.initials: S
authors.lastname: Shiratori
mesh_terms: D065966:Absorption, Physicochemical; D000818:Animals; D001777:Blood Coagulation; D032561:Cotton Fiber; D057927:Hydrophobic and Hydrophilic Interactions; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D056951:Photoelectron Spectroscopy; D011108:Polymers / Q000737:chemistry*; D034421:Sus scrofa; D014835:Volatilization; D014867:Water / Q000737:chemistry; D017155:Wettability
chemical_list: D011108:Polymers; D014867:Water
keywords: Janus membrane; cotton fabrics; mechanical durability; spray; superhydrophobicity