2019/11/15 by Daniel J. Arismendi‐Arrieta, Arismendi-Arrieta, Daniel J., Angel J. Moreno +1
Materials Science · Chemistry · #Pickering emulsions and particle stabilization #Surfactants and Colloidal Systems #Liquid Crystal Research Advancements
paper · pdf · doi:10.48550/arxiv.1911.06725
Soft nanoparticles hold promise as smart emulsifiers due to their high degree\nof deformability, permeability and stimuli responsive properties. By means of\nlarge-scale simulations we investigate the structural properties of nanogels at\nliquid-liquid (A-B) interfaces and the miscibility of the liquids inside the\nnanogels, covering the whole range of interfacial strength from the limit of\nsingle-liquid to the case of stiff interfaces. To study the role of the\ninternal architecture and deformability of the nanogel we simulate a realistic\ndisordered and an ideal regular network, for a broad range of cross-linking\ndegrees. Unlike in previous investigations on liquid miscibility, excluded\nvolume interactions are considered for both the monomers and the explicit\nsolvent particles. The nanogel permeability is analysed by using an unbiased\ngrid representation that accounts for the surface fluctuations and adds to the\ndensity profiles the exact number of liquid particles inside the nanogel. The\nbetter packing efficiency of the regular network leads to higher values of the\ntotal liquid uptake and the invasive capacity (A-particles in B-side and\nviceversa than in the disordered network, though differences vanish in the\nlimit of rigid interfaces. Uptake and invasion are optimized at a cross-linking\ndegree that depends on the interfacial strength, tending to 15 - 20% for\nmoderate and stiff interfaces. As the interfacial strength increases, the\nmiscibility inside the nanogel is enhanced by a factor of up to 5 with respect\nto the bare interface, with the disordered networks providing a better mixing\nthan their ideal counterparts. The emerging scenario reported here provides\ngeneral guidelines for tuning the shape, uptake, invasive, and mixing\ncapacities of nanogels adsorbed at liquid-liquid interfaces.\n