CO₂-Responsive Pickering Emulsions Stabilized by a Bio-based Rigid Surfactant with Nanosilica

Abstract

A novel CO 2 -responsive surfactant, maleopimaric acid glycidyl methacrylate ester 3-(dimethylamino)propylamine imide (MPAGN), based on sustainable resource of rosin was synthesized and used to prepare a kind of CO 2responsive Pickering emulsions with nanosilica. MPAGN can be reversibly responsive to CO 2 and N 2 between active cationic (MPAGNH + ) and inactive nonionic (MPAGN), leading to adsorb on or desorb from the surface of nanosilica, then stabilize or break emulsion. CO 2 -responsive behavior of MPAGN was verified by cycle change of pH and conductivity with bubbling CO 2 and N 2 alternately. The type of adsorption of MPAGNH + at the particle−water interface was explained according to the adsorption isotherms. The mechanisms of stabilization, destabilization, and restabilization of Pickering emulsion were analyzed according to zeta potentials and droplet size. This Pickering emulsion can be reversible between stable and unstable by bubbling CO 2 and N 2 alternately. Moreover, this emulsifier can be recycled when new oil was added after removing the initial oil. Therefore, it not only has economic benefits but also has an environmentally friendly property.

pH-Responsive Non-Pickering Emulsion Stabilized by Dynamic Covalent Bond Surfactants and Nano-SiO2 Particles

“…The ζ-potential measurement was used to study emulsions containing nanoparticles. − Nano-SiO 2 particles (0.5 wt %) were added to aqueous solutions of different concentrations of the surfactant (0.00025, 0.0005, 0.0025, 0.005, 0.0125, 0.025, 0.0375, 0.05, 0.07, 0.09, 0.1, 0.2, 0.3, 0.5, 0.7, and 0.9 M), and the pH was adjusted to 12.55. The ζ-potential values of the nano-SiO 2 particles were measured.…”

Hybrids of CO2-Responsive Water-Redispersible Single-Walled Carbon Nanotubes by a Surfactant Based on Natural Rosin

“…MPAGN was synthesized following our previous report. 32 A mixture of MPAGN (8 mg) and SWNTs (0.8 mg) in water (24 mL) bubbled with CO 2 was treated by sonication for 20 min (750 W and 20 kHz, Sonics), followed by centrifugation at 8000 rpm for 10 min to obtain a homogeneous dispersion of SWNTs with an adsorbed layer of MPAGN (U-SWNTs). The MPAGN monolayer on the SWNT surface was locked in by in situ free-radical polymerization (P-SWNTs), and the initiator was 2,2′-azobis(2-methylpropionamide)dihydrochloride (V50).…”

Photoresponsive Viscoelastic Solutions Based on Chiral Wormlike Micelles in Mixed Solutions Containing an Amphiphile Derived from Rosin

“…Generally, the biobased wormlike micelles are favorable biocompatibility and biodegradability, complying the sustainable development. , Rosin obtained from pine trees is an abundant biomass resource. − Its main component is resin acids. The rigid tricyclic hydrophenanthrene structure of resin acid contains a carboxylic acid and a conjugated double bond, allowing for convenient further modification. , Lots of rosin-based surfactants have been synthesized. ,− The large rigid skeleton of the rosin molecule dramatically facilitates the self-assembly of rosin-based surfactants. Abundant aggregations, such as vesicles, , nanofibers, , annular micelles, sponge-like micelles, and so on, have been prepared.…”

“…The rigid tricyclic hydrophenanthrene structure of resin acid contains a carboxylic acid and a conjugated double bond, allowing for convenient further modification. 44,45 Lots of rosin-based surfactants have been synthesized. 8,43−48 The large rigid skeleton of the rosin molecule dramatically facilitates the self-assembly of rosinbased surfactants.…”