ИСТИНА

Internal structure of microgels (μGs) resembles elements of macroscopic polymer network: linear chains (subchains) are covalently linked with each other into three-dimensional frame of the size in the range between tens of nanometers and few microns. They reveal duality in the properties: liquid-like behavior is characteristic at the small length scales and the elastic response appears at the length scales larger than the mesh size. This fact attributes the μGs to very promising materials for many applications including emulsion stabilization, drug delivery, etc. Up to now most attention was paid to the spherical microgels. They are well studied theoretically, experimentally and by the means of computer modeling. But with the development of the synthesis methods, microgels of complex structure can be produced. So we can choose the form of synthesized microgels and produce, for example, rod-shape microgels using microfluidic methods. Such objects are obtained experimentally, but still there are no theoretical or other researches of their properties. In this work we focused on non-spherical microgels’ swelling and collapse features. As a simulation object an ellipsoidal microgel was chosen. To conduct the computer simulations two methods were used: dissipative particle dynamics (DPD) and molecular dynamics (MD). Calculations were carried out by means of “Lomonosov” cluster. Quality of the solvent was controlled by the monomer interaction energy. One may suppose that as solvent degrades the microgel will collapse self-similar. Though non self-similar collapse was discovered: microgels demonstrated conformational transition from ellipsoid to sphere while the quality of solvent went downhill. We suppose that such a behavior appeared because of bulk and surface forces competition. In increasingly degradating solvent microgel tended to adopt the least surface energy conformation – the sphere. This result was observed without reference to cross-linking density by both of simulation methods. In this way, non-spherical microgels appears to be objects with nontrivial properties and need further investigation.