Fully bio-based CO2-responsive pickering gel emulsions stabilized by cellulose nanocrystals combined with a rosin-based surfactant

Pickering Emulsions and Viscoelastic Solutions Constructed by a Rosin-Based CO2-Responsive Surfactant

“…The carbon atom number of the hydrocarbon chain of ionic surfactant was usually in the range of 8–16 atoms, and the critical micelle concentration of its aqueous solution decreased with the increase of carbon atom number. However, the critical micelle concentration (CMC) of the C 16 MPAN + solution was about 2.5 mM (Figure ), higher than that of a reported surfactant N-decyl-maleimidepimaric acid N,N-dimethylenediamide bicarbonate (C 10 MPAN + , 0.04 mM) . It was indicated that increasing the length of the hydrocarbon chain in the presence of the rigid structure of rosin would cause a decrease in the aggregation ability of the surfactant in aqueous solution.…”

“…The molecular structure and surface activity of stimuli-responsive surfactants can be reversibly converted in solution by various triggers, such as pH, , CO 2 /N 2 , − light, − temperature, , redox, − magnetic, , ionic strength, , and so on. For smart surfactant, its aqueous solution can obtain or lose viscoelasticity by switching between ionic and nonionic forms, and it can also absorb or desorb on the surface of nanoparticles to cause the Pickering emulsion to emulsify or demulsify . CO 2 /N 2 as a trigger is particularly attractive with nontoxic, noncorrosive, easily removed from the system, cheap, and environmentally friendly .…”

“…For smart surfactant, its aqueous solution can obtain or lose viscoelasticity by switching between ionic and nonionic forms, and it can also absorb or desorb on the surface of nanoparticles to cause the Pickering emulsion to emulsify or demulsify. 47 CO 2 /N 2 as a trigger is particularly attractive with nontoxic, noncorrosive, easily removed from the system, cheap, and environmentally friendly. 32 For example, Liu et al 32 first reported in 2006 that long-chain alkamidine can be converted between nonionic and ionic by bubbling CO 2 and N 2 .…”

CO2-responsive gels

“…A diverse range of CO 2 -responsive materials has been formed. These include polymers and polymer colloids; 50,53,[58][59][60][61] solvents, 54,62,63 catalysts, [64][65][66] and surfactants; 54,67,68 surfaces and coatings; 69,70 emulsions; [71][72][73][74][75] foams; [76][77][78] membranes; 63,79,80 particles and latexes; [81][82][83] cotton fibres, [84][85][86] and ionic liquids. [87][88][89] Similarly, CO 2 -induced self-assembled structures with complex morphologies have been realised including vesicles, 90,91 worm-like micelles, [92][93][94] and nano-objects.…”

CO2-Responsive Rosin-Based Supramolecular Hydrogels: Diverse Chiral Nanostructures and Their Application in In Situ Synthesis of Chiral Gold Nanoparticles

“…As wellknown, tertiary amine-based surfactants could be switched between their active form (bicarbonate/cationic) and inactive form (amidine/neutral) by alternatively bubbling CO 2 and N 2 . 38 As shown in Figure 1a, bubbling CO 2 into the aqueous solutions of C n MPAN, it was protonated and transformed into cationic tertiary amine bicarbonate (C n MPANB), which exhibited excellent water solubility, and C n MPANB would switch back to C n MPAN through bubbling N 2 . Interestingly, CO 2 -responsive hydrogels were formed with further increasing the C n MPAN concentration.…”