Modified sodium lignosulfonates (NaLS) with straight chain alcohols and their aggregation behavior and adsorption characteristics on solid surfaces

Abstract

Abstract The aim of the present study is to reveal the effects of straight chain alcohols (CnOHs, 4<n<12) on the aggregation and adsorption behavior of sodium lignosulfonate (NaLS). The analytical methods zeta potential measurement and laser particle size analysis are in focus, while the adsorption characteristics of the samples are studied by means of electrostatic layer-by-layer self-assembly (LBL-SA), atomic force microscopy (AFM), UV spectroscopy, and a quartz crystal microbalance with dissipation (QCM-D) monitoring. The results indicated that the electronegative character of NaLS molecules increased and the aggregation degree of NaLS in solution diminished due to hydrophobic interactions between the hydrophobic core of NaLS and the alkyl chain of alcohols. The adsorption configuration of NaLS without CnOHs is a mushroom-like structure on the solid quartz surface, of which cation-π is the main driving force. In the presence of alcohols, the adsorption morphology of NaLS on the quartz surface changed from compact rigid to a less compact soft state. The adsorption configuration of NaLS with alcohols assumed the shape of polymer brushes, in which electrostatic interaction played an important role. Therefore, the adsorption amount of NaLS on solid surfaces significantly increases in the presence of alcohols, which facilitate the formation of more uniform and smooth adsorption films.