Thermodynamics of the aggregation of imidazolium ionic liquids with sodium alginate or hydroxamic alginate in aqueous solution

A detailed assessment on the interaction of sodium alginate with a surface-active ionic liquid and a conventional surfactant: a multitechnique approach

“…This complexation ability originates from the coulombic attraction between the oppositely charged polyions and surfactant monomers as well as the hydrophobic attraction among the apolar chain of surfactants, hydrophobic moieties of polyelectrolytes and tails of surfactants. Recently, [15][16][17][18][19] growing interest is directed to the interaction of carbohydrate type polyelectrolytes with surface active ionic liquids (SAIL) in aqueous solution. [15][16][17][18][19] Carbohydrate based polymers gain special attraction owing to their biocompatible, biodegradable and low immunogenic nature 17,20,21 and on the other hand, SAILs can improve the mechanical, thermal and electrochemical properties of materials in addition with polymers in industrial arenas.…”

“…Recently, [15][16][17][18][19] growing interest is directed to the interaction of carbohydrate type polyelectrolytes with surface active ionic liquids (SAIL) in aqueous solution. [15][16][17][18][19] Carbohydrate based polymers gain special attraction owing to their biocompatible, biodegradable and low immunogenic nature 17,20,21 and on the other hand, SAILs can improve the mechanical, thermal and electrochemical properties of materials in addition with polymers in industrial arenas. For example, ILs have been used as curing agents, 22 modifiers of glass transition temperature, 23 conducting agents in polymer electrolyte film 24 as well as building blocks of polymer matrices, 25 plasticizers for polysaccharides 26 and also heterogeneous catalysts in conjugation with polyelectrolytes.…”

“…27 Moreover, easy tuning of hydrophobic moieties and also counterions makes the ionic liquids ('designer solvents') attractive in recent scenarios over conventional surfactants. 28 Sodium alginate (NaAlg), an anionic biodegradable polysaccharide, has been synthesized from marine brown algae containing 1-4 linked a-L-guluronic (G) and b-Dmannuronic (M) acid residues arranged in an irregular blockwise pattern of varying proportions of GG, MG, and MM blocks, and widely used 12,17,20,22,29 in medical and pharmaceutical industries as gelling agents and in food industries as a stabilizer and thickener. 21,29 This anionic polyelectrolyte (block copolymers) has enormous uses for the production of bio films, bandages, beads, nanoparticles, and microcapsules by recognising its significant biocompatible stable gelling properties 29,30 which is obtained mainly by incorporation of surfactants and inorganic salts (K 2 CO 3 , CaCO 3 , etc.)…”

“…Of late, although a significant amount of research work has been devoted to elucidating the physicochemical parameters for another biodegradable polyelectrolyte, sodium carboxymethylcellulose (NaCMC) with imidazolium SAILs in aqueous solution by researchers, 16,18,19,[33][34][35] a comprehensive physicochemical investigation on the interaction of NaAlg with imidazolium ionic liquids in aqueous solution at low to moderately high polyelectrolyte concentration is scarcely found in the literature. 17 In this present study, an investigation has been performed on the aggregation phenomena and the thermodynamics of a cationic SAIL 1-hexadecyl-3-methylimidazolium chloride (C 16 MeImCl), and a conventional surfactant 1-hexadecyl triphenylphosphonium bromide (C 16 TPB) in aqueous solution in the absence as well as in the presence of NaAlg as a function of polyelectrolyte concentration as probed by tensiometry, conductometry, isothermal titration calorimetry (ITC), steady state and time resolved fluorimetry and dynamic light scattering at 298.15 K. Characterization of NaAlg-surfactant complexes (PS-complex) was performed using the FTIR-ATR technique. Fluorescence imaging and high-resolution transmission electron microscopy (HR-TEM) were used for the visual impression of the polyelectrolyte surfactant complex (PS-complex) mediated by NaAlg with different surfactants investigated here, and also determining its size and shape.…”

“…Of late, although a significant amount of research work has been devoted to elucidating the physicochemical parameters for another biodegradable polyelectrolyte, sodium carboxymethylcellulose (NaCMC) with imidazolium SAILs in aqueous solution by researchers, 16,18,19,33–35 a comprehensive physicochemical investigation on the interaction of NaAlg with imidazolium ionic liquids in aqueous solution at low to moderately high polyelectrolyte concentration is scarcely found in the literature. 17…”