Morphological and property studies of charged pentablock terpolymer gels containing an aliphatic oil

Thermoplastic elastomers (TPEs) derived from styrenic block polymers are versatile materials capable of combining elastic properties with the melt processability and solid properties of thermoplastics, allowing for effective application in ubiquitous technologies. They can be physically modified through the addition of a selective liquid, such as a low-volatility oil, to create TPE gels (TPEGs) typically exhibiting improved mechanical properties. The present study focuses on morphological and property development in charged TPEGs prepared from a midblock-sulfonated pentablock terpolymer with up to 50 wt% mineral oil. The parent TPE possesses a unique range of properties suitable for applications such as rapid, broad-spectrum antimicrobial surfaces. While the morphologies of the charged TPEGs are sensitive to solvent-vapor annealing, their corresponding mechanical properties are highly dependent on oil loading level, as evidenced by substantial changes in flexibility and maximum strain. Moreover, the antimicrobial efficacy against ampicillin-resistant E. coli has been evaluated and found to decrease with increasing oil content due to extensive oil coverage on the TPEG surfaces. Our observations reported here highlight a critical trade-off between antimicrobial properties and improved mechanical properties, in which case the oil content can be tailored to meet specific application requirements.