Tuning the Wettability and Surface Free Energy of Poly(vinylphenol)Thin Films by Modulating Hydrogen-Bonding Interactions

• Main Authors: Chih-Feng Wang, Dula Daksa Ejeta, Jian-Yi Wu, Shiao-Wei Kuo, Ching-Hsuan Lin, Juin-Yih Lai
• Format: Article
• Language: English
• Published: MDPI AG 2020-03-01
• Series: Polymers
• Subjects: poly(vinyl phenol), surface free energy; intermolecular interaction; hydrogen bonding
• Online Access: https://www.mdpi.com/2073-4360/12/3/523

The ability to tune the surface properties of a polymer film in a simple and effective manner is important for diverse biological, industrial, and environmental applications. In this work, we investigated whether or not the surface free energy of poly(vinyl phenol; PVPh) can be tuned by adjusting the casting solvent and the thermal treatment time, which alters the proportions of intra-and intermolecular hydrogen bonding interactions. Compared to the untreated sample, in tetrahydrofuran (THF) system, the thermal treatment resulted in a lower proportion of intermolecular hydrogen bonds and a concomitant decrease in the surface free energy (from 39.3 to 18.8 mJ/m²). In contrast, the thermal treatment in propylene glycol methyl ether acetate (PGMEA) and ethyl-3-ethoxypropionate (EEP) systems increased the proportion of intermolecular hydrogen bonds and the surface free energy of the polymer thin films, from 45.0 to 54.3 mJ/m² for PGMEA and from 45.5 to 52.9 mJ/m² for EEP. Controlling intermolecular hydrogen-bonding interactions is a unique and easy method for tuning the surface free energies of polymer substances.