Solvent Induced Inversion of Core–Shell Microgels

Abstract

The morphology of core–shell microgels under different swelling conditions and as a function of the core–shell thickness ratio is systematically characterized by mesoscale hydrodynamic simulations. With increasing hydrophobic interaction of the shell polymers, we observe drastic morphological changes from a core–shell structure to an inverted microgel, where the core is turned to the outside, or a microgel with a patchy surface of core polymers directly exposed to the environment. We establish a phase diagram of the various morphologies. Moreover, we characterize the polymer and microgel conformations. For sufficiently thick shells, the changes of the shell size upon increasing hydrophobic interactions are well described by the Flory–Rehner theory. Additionally, this theory provides a critical line in the phase diagram separating core–shell structures from the distinct two other phases. The appearing new phases provide a novel route to nano- and microscale functionalized materials.

Modelling realistic microgels in an explicit solvent

“…Indeed, at each swelling stage, the microgel has a similar structure regardless of the solvent employed, suggesting that deswelling occurs via the same sequence of transient states. It would be interesting to compare these findings with more accurate solvent treatments such as Multi-Particle-Collision-Dynamics simulations 13 , 14 .…”

Time-resolved structural evolution during the collapse of responsive hydrogels: The microgel-to-particle transition

“…Second, theoretically, by mesoscale hydrodynamic computer simulations allowing for a systematic investigation of the key parameters governing the collapse while providing structural insight during the collapse process. Specifically, we exploit the multiparticle collision dynamics (MPC) approach for the fluid combined with molecular dynamics simulations for the polymers ( 49 , 50 ). The MPC method captures thermal fluctuations and has been shown to correctly account for hydrodynamic interactions (HIs) ( 51 ), that is, it captures fluid-mediated interactions and reproduces the hydrodynamic properties of polymers in solution ( 51 ), the dynamics of which is typically accelerated by the emerging flow fields of fluctuating or dragged monomers.…”

The influence of an applied magnetic field on the self-assembly of magnetic nanogels

“…The importance of micro-and nanogels stimulated the application of many different approaches, experimental and theoretical, to study their structural, mechanical, and rheological properties [48][49][50][51][52][53][54][55][56][57][58][59][60]. In particular, computer simulations on these systems have experienced an important development in very recent years with the adoption of a more realistic representation of the polymer network, moving away from the lattice or regular structures used in former models [57,61,62].…”