Low-Temperature Argon Plasma-Assisted Biofilm Colonization on Poly(<scp>l</scp>-Lactic Acid)/ Polyhydroxyalkanoate-Copolymer Cast Film for Enhanced Soil Biodegradation

The surfaces of poly(l-lactic acid) (PLA), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx), and their cast-film blends were activated using low-temperature argon plasma to confirm the possibility of improved microbial adhesion and biodegradation rate using soil microflora as a degrading medium. Radio frequency (RF) plasma systems selectively altered the surface characteristics of PLA/PHBHHx blend cast films without significantly affecting their bulk properties. Notably, Ar-etching (12 min, 50 W) promoted a strong hydrophilic behavior (up to 25 ± 2°), surface energy (up to 48 ± 5%), and surface roughness by ∼4-fold. The increased wettability on plasma-treated samples could be linked to the introduction of polar groups (C–O and O═C–O) and formation of distinct rough topographical structures, which provide a conducive microenvironment for the initial microbial attachment and subsequent biofilm formation. The enhanced wettability favors abiotic hydrolysis by promoting biofilm formation (30 ± 5%), which in turn stimulates the biodegradation rate by 1.1–1.5-fold. These findings indicate that surface activation by argon plasma is a sustainable and viable strategy to enhance cell-surface interactions and biodegradation of biopolymers.