Imidazolium surface-active ionic liquids as antifungal agents in wood protection

Abstract

This research focuses on five newly surface-active ionic liquids (SAILs) whose commitment to sustainable chemistry allows for their utilization as effective wood protection agents alternatives to traditional surfactants. The synthesis yields were above 93 %, while the purity ranged from 97 to 99 %. Also, a series of properties such as surface activity, wettability, antifungal properties were studied. The demonstrated relationship between critical micelle concentration (CMC) and elongation on alkyl chain length of the investigated imidazolium SAILs aligns with expectations. Moreover, it was shown that all tested SAILs exhibited lower CMC values (ranged from 0.34 to 8.46 mmol⋅L−1) than conventional surfactants such as didecyldimethylammonium chloride (DDAC) and decyltrimethylammonium bromides (CTAB) proving that the synthesized compounds can serve as substitutes for surfactants. 3-Decyloxymethyl-1-methylimidazolium dicyanamide (SAIL-3) showed the best antifungal properties, which does not translate into contact angle (CA) values. The mechanical properties measured for the impregnated wood samples were consistently inferior to those of the control wood samples. However, wood treated with SAIL-3, in contrast, exhibited a reduced uptake of free water compared to the untreated control wood. The results presented validate our hypothesis regarding the distinctive nature of SAILs and affirm their suitability for wood impregnation.