Controlling Lengthscales in Water-Solvent Induced Self-Organized Dewetting of Thin Polystyrene Films by Modulating the Surface Properties of the Substrate. Issue 7 (3rd August 2022)

• Record Type: Journal Article
• Authors: Yadav, Priti; Dubey, Nidhi; Verma, Ankur
• Is Part Of: Journal of macromolecular science. Volume 61:Issue 7/8(2022)
• Page Start: 914
• Page End: 925
• Publication Date: 2022-08-03
• Subjects: contact-angle -- dewetting -- octadecyltrichlorosilane -- self-assembled monolayers -- self-organization -- silanization; Polymerization -- Periodicals; Polymers -- Periodicals; 530.413
• DOI: 10.1080/00222348.2022.2118482
• Languages: English
• ISSNs: 0022-2348

Abstract

Abstract: We report here a facile method of modulating the lengthscales of self-organized dewetting of polystyrene thin films by varying the extent of silane grafting on the substrate. The self-assembled monolayers (SAM) of octadecyltrichlorosilane (OTS) were grafted on glass substrates by exposing them to different doses of OTS vapors in a controlled, low pressure environment. Measurement of water contact angles on the modified glass surfaces showed that the contact angles could be continuously increased from 40° to 70° by increasing the time of exposure to the OTS vapors from a few minutes to several hours. Polystyrene (PS) thin films were spin coated on the modified glass substrates and water-solvent mixture induced dewetting of the PS thin films was carried out, where the dewetting kinetics depended on the spreadability of water on the surface. We observed a reduction in the length scales of the dewetting, i.e. the wavelength of instability ( λ ) and droplet size ( d ), by increasing the extent of OTS exposure. The λ for a 50 nm thick PS film decreased from 12 to 4 µm while the droplet diameter ( d ) also decreased, from 2.5 to 1.6 µm.