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

Chih-Feng Wang,Jian-Yi Wu,Juin-Yih Lai,Shiao-Wei Kuo,Dula Daksa Ejeta,Ching-Hsuan Lin

doi:10.3390/polym12030523

Abstract

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.

Highlights

The surface properties of a solid substance, such as adhesion, wettability, and surface roughness are significant characteristics for biological, industrial, and environmental applications
We discovered that the surface free energy of a PVPh thin film is tunable over the 18.8–54.3 mJ/m2 range by merely changing the casting solvent and the thermal treatment time
The surface properties of a polymeric material can be adjusted by tuning the fractions of inter4

Summary

Introduction

The surface properties of a solid substance, such as adhesion, wettability, and surface roughness are significant characteristics for biological, industrial, and environmental applications. Current approaches for shaping the wettability properties and surface free energy of a polymer material include plasma modification or other methods [1,2,3,4]. Intra- and intermolecular hydrogen bonds play significant roles in defining the surface properties of a polymeric material. Hydrogen bonds can be intramolecular (within a single molecule) or intermolecular (between molecules). Polymers 2020, 12, 523 molecule, whilst an intermolecular hydrogen bond is formed between two different molecules. In a given polymer chain, either intra- or inter-chain hydrogen bonding can be built by the same functional groups [5]. Polypeptide α-helix and β-sheet structures are stabilized by inter-chain and intra-chain hydrogen bonds, respectively [6,7]

Methods

Results

Conclusion