FisMat2017 - Submission - View

Abstract's title: Magnetic microgels in computer simulations
Submitting author: Elena Minina
Affiliation: University of Vienna
Affiliation Address: Sensengasse 8, 1090, Vienna
Country: Austria
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: C.N. Likos (University of Vienna), S.S. Kantorovich (University of Vienna)

Microgels, colloidal particles consisting of cross-linked polymers, are able to swell or shrink as a response to their external environment [1]. The fact that the swelling can be controlled makes microgels promising materials for many applications. However, embeding magnetic particles into such systems has to change their behaviour dramaticlaly and, therefore, offers an additional machanism to control microgel properties. For example, elastic and magnetic response of soft materials to the surrounding environment can change as it has been demonstrated in the resent works on the novel magnetic dipolar materials like magnetic gels and filaments [2-4].

In this work, we study the behavior of magnetic microgels and their elastic properties by means of molecular dynamic computer simulations. Initially, we construct a microgel as a non-magnetic polymer network of spherical shape which has been cross-linked randomly. Then, randomly embading magnetic particles into such reference systems, we obtain magnetic microgels with different volume fraction of magnetic particles that varies from 0.5 to 10 per cent of the total volume fraction of particles comprising the polymer network of the microgel. Stydying such systems at different strength of dopole-dipole interactions and solvent, we estimate the change of magnetic microgel in size and its conformations comparing to its reference non-magnetic counterpart. In order to investigate elastic properties, we place the microgel particles between two planar walls. Sqeezing the the gel between the walls consequently and measuring the elastic propesties without magnetic field as well as in a magnetic field applied perpendicular to the walls with different strength, we observe that the contribution of magnetic dipolar interactions and the magnetic field play a significant role in controling elastic properties and therefore in manipulation of such material.

[1] A. Fernandez-Nieves, H. M. Wyss, J. Mattsson, and D. A. Weitz. Microgel Suspensions: Fundamentals and Applications. 2011.

[2]  R. Weeber, S. Kantorovich, and C. Holm, J. Chem. Phys. 143 (15) (2016).

[3] P.A. Sanchez, E.S. Pyanzina, E.V. Novak, J.J. Cerda, T. Sintes and S.S. Kantorovich, Faraday Discuss. 186, 241 (2016).

[4] P.A. Sanchez, E.S. Pyanzina, E.V. Novak, J.J. Cerda, T. Sintes and S.S. Kantorovich, Macromolecules 48 (20), 7658 (2015)