title: Controlled Fabrication of Polypyrrole Surfaces with Overhang Structures by Colloidal Templating.
abstract: Here we present the fabrication of polypyrrole (PPy) surfaces with a controlled overhang structure. Regularly structured PPy films were produced using interfacial polymerization around a sacrificial crystalline colloidal monolayer at the air/water interface. The morphology of the final inverse colloidal PPy film is controlled by the amount of monomer, the monomer: oxidant ratio and polymerization time. The PPy films exhibit an overhang structure due to depth of particle immersion in the water phase. As a result of the overhang structure, the PPy films are made hydrophobic, although the material itself is hydrophilic. The apparent contact angle of water on the structured surfaces is 109.5°, which is in agreement with the predicted contact angle using the Cassie-Baxter equation for air-filled cavities. This fabrication technique is scalable and can be readily extended to other systems where controlled wettability is required.
authors.affiliation: †Physical Chemistry and Soft Matter, Wageningen University, Dreijenplein 6, 6703 HB Wageningen, The Netherlands.
authors.forename: Sabine
authors.initials: S
authors.lastname: Akerboom
authors.affiliation: ‡Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands.
authors.forename: Sidharam P
authors.initials: SP
authors.lastname: Pujari
authors.affiliation: §Department of Engineering, Physics McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7, Canada.
authors.forename: Ayse
authors.initials: A
authors.lastname: Turak
authors.affiliation: †Physical Chemistry and Soft Matter, Wageningen University, Dreijenplein 6, 6703 HB Wageningen, The Netherlands.
authors.forename: Marleen
authors.initials: M
authors.lastname: Kamperman
keywords: Cassie−Baxter model; colloidal templating; interfaces; overhang structure; polypyrrole; wetting