Deformability and solvent penetration in soft nanoparticles at liquid-liquid interfaces

Abstract

Soft nanoparticles hold promise as smart emulsifiers due to their high degree of deformability, permeability and stimuli responsive properties. By means of large-scale simulations we investigate the structural properties of nanogels at liquid-liquid (A-B) interfaces and the miscibility of the liquids inside the nanogels, covering the whole range of interfacial strength from the limit of single-liquid to the case of stiff interfaces. To study the role of the internal architecture and deformability of the nanogel we simulate a realistic disordered and an ideal regular network, for a broad range of cross-linking degrees. Unlike in previous investigations on liquid miscibility, excluded volume interactions are considered for both the monomers and the explicit solvent particles. The nanogel permeability is analysed by using an unbiased grid representation that accounts for the surface fluctuations and adds to the density profiles the exact number of liquid particles inside the nanogel. The better packing efficiency of the regular network leads 1 arXiv:1911.06725v1 [cond-mat.soft] 15 Nov 2019to higher values of the total liquid uptake and the invasive capacity (A-particles in B-side and viceversa) than in the disordered network, though differences vanish in the limit of rigid interfaces. Uptake and invasion are optimized at a cross-linking degree that depends on the interfacial strength, tending to ∼ 15 − 20 for moderate and stiff interfaces. As the interfacial strength increases, the miscibility inside the nanogel is enhanced by a factor of up to 5 with respect to the bare interface, with the disordered networks providing a better mixing than their ideal counterparts. The emerging scenario reported here provides general guidelines for tuning the shape, uptake, invasive, and mixing capacities of nanogels adsorbed at liquid-liquid interfaces.

Microgels at Interfaces Behave as 2D Elastic Particles Featuring Reentrant Dynamics

“…So far, the effects that an interfacial confinement induces on such particles have been mainly limited to the study of their characteristic shape, and hence, to their structural arrangement at oil-water and air-water interfaces. These aspects have been widely investigated experimentally [30,31] and, more recently, also numerically [29,32,33].…”

Interfacial Synthesis: Morphology, Structure, and Properties of Interfacial Formations in Liquid–Liquid Systems

“…"Soft" nanoparticles are promising smart emulsifiers due to the high degree of their deformability and permeability. Nanogels at liquid-liquid interfaces can be tuned to a certain miscibility of liquids and absorption and invasive capacity, which is important in chemical separation [177].…”

Capillary interactions between soft capsules protruding through thin fluid films

“…13,[33][34][35][36] Furthermore, molecular dynamics, dissipative particle dynamics, lattice Boltzmann and mean field simulations were applied to investigate various properties of soft particles at fluid interfaces. [37][38][39][40][41][42] While molecular dynamics simulations are not capable to study the influence of the particle softness and the surface wetting properties for many particles at a fluid-fluid interface due to the prohibitive computational effort, dissipative particle dynamics and mean field approaches overcome this limitation by reducing the resolved details of the particle structure. However, to the best of our knowledge, the detailed influence of the particle softness on the lateral forces and on aggregation properties has not been systematically studied in experiments or simulations.…”