Water Repellency of Bottlebrush Polymers Consisting of Monomer Units with a Long Alkyl Chain Synthesized by Ru-Catalyzed Living Radical Polymerization

• Published in: ACS applied polymer materials Vol. 1; no. 12; pp. 3422 - 3431
• Main Authors: Murase, Nobuo, Terada, Kayo, Ando, Tsuyoshi, Shibutani, Shota, Tanaka, Yoshito, Kawabe, Takuma
• Format: Journal Article
• Language: English
• Published: American Chemical Society 13.12.2019
• Subjects: long alkyl chain; living radical polymerization; surface property; water repellency; bottlebrush polymer
• ISSN: 2637-6105; 2637-6105
• DOI: 10.1021/acsapm.9b00852

Over the past few decades, techniques for improving the surface properties of various materials have been actively researched. In particular, water repellency is an important factor for controlling surface properties, with a wide range of potential applications. The synthesis of unique structural polymers, such as multibranched polymers, has become relatively easy via living radical polymerization. These multibranched polymers exhibit unique physical properties compared with linear polymers due to different solution viscosities and crystallization behaviors based on entanglement among macromolecules. Herein, we report the synthesis of a polymer with a Br-initiating group on the side chain and the polymerization of various alkyl-chain-containing monomers from the Br-initiating group by Ru-catalyzed living radical polymerization to produce bottlebrush polymers with a multibranched structure. We evaluated the water and CH2I2 contact angles of these polymers in comparison with a linear polymer. The water and CH2I2 contact angles of bottlebrush polymers were slightly larger than those of linear polymers. Moreover, a bottlebrush polymer synthesized by using stearyl methacrylate (C18) with a long alkyl chain exhibited a larger contact angle than those synthesized using tetradecyl methacrylate (C14) and methyl methacrylate (C1), and the sliding angle of poly­(stearyl acrylate) was improved by changing the polymer architecture from a linear polymer to a bottlebrush polymer. In addition, we demonstrate a facile method for achieving a finely rough surface by polymer aggregation to improve the water repellency by combining a good solvent with a low boiling point and a poor solvent with a high boiling point. We obtained a finely rough surface from the aggregation of a bottlebrush polymer, which differed from that of a linear polymer, and observed an increased water contact angle for a bottlebrush polymer thin film coated on a PET substrate.