Modulating effect of different biomolecules and other additives on cloud point and aggregation of amphiphilic linear and starblock copolymer

Abstract

Non-ionic surfactants based on ethylene oxide-propylene oxide (EO-PO) block copolymers find applications in various industries including pharmaceutics, cosmetics, cleaning and dispersion sciences. This work shows the comparison among the clouding behaviour of two moderately hydrophobic EO-PO block copolymers viz. linear triblock Pluronic® P104 and starblock Tetronic® T1304 (henceforth mentioned as P104 and T1304), showing the effect of several additives viz. inorganic salts (NaCl, NaF, NaBr, NaI, NaCNS, Na2SO4, NaNO3), sugars (dextrose, sucrose, maltose, mannitol, sorbitol), amino acids (glycine, alanine, valine, serine, lysine, leucine, histidine, glutamine), ureas [urea, thiourea, N-methylurea (MMU), N,N′-dimethylurea (DMU), N, N, N′ N′-tetramethylurea (TMU), phenylurea], alcohols [ethanol, 1-butanol, 1-hexanol, 1-octanol, trifluoroethanol (TFE)], diols (ethylene glycol, 1,4-butanediol, 1,6-hexanediol,1,8-octanediol), water soluble polymers [polyvinyl alcohol (PVA 160K, PVA 49K), polyethylene glycol (PEG 300K, PEG 8K), polyvinylpyrrolidone (PVP 55K), and alkyl methylimidazolium ionic liquids [1-butyl-3-methylimidazolium chloride (C4mimCl), 1-butyl-3-methyl imidazolium hexafluorophosphate (C4mimPF6), 1-butyl-3-methyl imidazolium trifluoromethanesulfonate (C4mimCF3SO3), 1-methyl-3-octylimidazolium chloride (C8mimCl), 1-decyl-3-methylimidazolium chloride (C10mimCl)]. The effect of these additives is described in terms of their molecular characteristics and interaction with water or the copolymer. Both, hydrophobicity and structural properties of additives play important roles in the observed cloud point variation. Dynamic light scattering results on apparent micelle size for selected system are also reported. Tuning of phase and aggregation behaviour of ethylene oxide based non-ionic amphiphiles is of industrial and biomedical importance.