Surface Properties of Alkyldi(oxyethylene) β-D-Maltoside

Abstract

A series of nonionic disaccharide-based surfactants alkyldi­(oxyethylene) β-d-maltosides (4a–4h, n = 6–16) were synthesized, and their physicochemical properties were further investigated. Six β-D-maltosides (4c–4h, n = 8–16) exhibited a fan-shaped texture feature, whereas hexyldi­(oxyethylene) β-D-maltoside (4a) had the strongest hygroscopicity. Owing to the incorporation of the hydrophilic dioxyethyl spacer (−(OCH2CH2)2−), the related water solubility improved significantly. Tetradecyldi­(oxyethylene) β-D-maltoside (4g) had good water solubility, whereas hexadecyldi­(oxyethylene) β-D-maltoside (4h) had weak water solubility. Meanwhile, the surface tension of β-D-maltosides (4a–4g, n = 6–14) had a decreasing tendency with increasing the alkyl chain length, whereas 4g had the best surface activity. Furthermore, decyldi­(oxyethylene) β-D-maltoside (4e) had the best foaming ability and foam stability. Dodecyldi­(oxyethylene) β-D-maltoside (4f) had the best emulsifying property in the rapeseed oil/water system. In contrast, both ammonium dodecyl sulfate (NH4DS)/4f and cetyltrimethylammonium chloride (CTAC)/4f binary surfactant systems showed a synergistic effect in surface activity because the C CMC/CMCid mix was <1. NaCl impacted the surface activity of the aqueous 4f solution through salt–surfactant synergistic effects. The results showed that such surfactants should have potential applications in the related field in the future.