A rheological investigation of sol–gel transition of hydroxypropyl cellulose with nonionic surfactant sorbitan monopalmitate: Modulation of gel strength by UV irradiation

Effect of Surfactant Tail Length on the Hydroxypropyl Cellulose-Mediated Premicellar Aggregation of Sodium n-Alkyl Sulfate Surfactants

“…sulfate (anionic, SDS), ,,,, carboxylate (anionic, e.g. sodium cholate), , benzyl sulfonate (anionic, dodecyl benzyl sulfonate), , imidazolium (cationic, 1-decyl-3-methylimidazolium chloride), trialkyl-ammonium (cationic, e.g., cetyltrimethylammonium bromide). , These studies infer that an attractive interaction between HPC and ionic-surfactant increases its cloud point temperature, solution viscosification, reduced counterion binding, and overall negative enthalpy change. , On the other hand, an increase in surfactant tail-length (or number of carbon atoms, n c ) enhances PS stability, growth rate, and HPC-surfactant binding cooperativity. ,,, All these results collectively propose that during PS formation charge–dipole interaction play a dominant role; however, short-range hydrophobic forces also play a meaningful role in the overall free energy change. Moreover, earlier studies ,,, have revealed that anionic surfactants, specifically those having sulfate headgroup, make a stronger interaction with HPC than the cationic ones.…”

“…sulfate (anionic, SDS), 16,19,21,23,25 carboxylate (anionic, e.g. sodium cholate), 25,32 benzyl sulfonate (anionic, dodecyl benzyl sulfonate), 23,33 1-decyl-3-methylimidazolium chloride), 5 trialkyl-ammonium (cationic, e.g., cetyltrimethylammonium bromide). 16,19 These studies infer that an attractive interaction between HPC and ionic-surfactant increases its cloud point temperature, 16 solution viscosification, 16 reduced counterion binding, 36 and overall negative enthalpy change.…”

“…Hydroxypropyl cellulose (HPC) is a hydrophobically modified nonionic cellulose polymer and suitable in biological framework because of its low toxicity, excellent biodegradability and biocompatibility . Besides, the solution properties of HPC or cellulose-related polymers and their interaction with different surfactants are well recognized. ,,− ,,,,− Role of charge-dipole interaction during HPC/surfactant association has been explored by varying the charge nature of surfactant headgroups e.g. sulfate (anionic, SDS), ,,,, carboxylate (anionic, e.g.…”

Interaction of HPC with CTAB and Tween 40 at Water/Air and Water/Soya Oil Interfaces

“…The corresponding ranges for HPC + Tween 40 systems are 6.41 × 10 –1 –7.09 × 10 –1 and 16.40 × 10 –1 –23.30 × 10 –1 , respectively. The higher value of m in the second shear-thinning region can be attributed to the disentanglement of the polymer coils in the solution and their enhanced orientation along the direction of flow when the yield stress is exceeded . The values of m along with other parameters for different polymer–surfactant mixtures tested are given in Table S1.…”

“…Steady-State Shear Rheology. The flow behaviors of aqueous solutions of 10% HPC/mixed systems of 10% HPC with varying concentrations of Tween 40/CTAB represent typically plastic systems with two distinct regions, viz., Newtonian followed by pseudoplastic (shear thinning) (Masrat et al, 2016), 62 as visualized clearly from their steady shear rheograms presented in Figure 1a,b. This behavior can be attributed to the presence of cross-linked superstructures corresponding to the high viscosity value up to a definite value of shear rate known as the critical shear rate.…”