Self-assembly and dynamic response of supracolloidal magnetic polymers

Research questions:

The main advantage of magnetic colloidal particles and materials based on them, particularly polymer-colloid hybrid materials, is that their properties and response can be controlled by applied magnetic ﬁelds [1,2]. The idea to build magnetically sensitive supracolloidal magnetic polymers (SMP) is very attractive, albeit challenging, as until today the fundamental understanding of the SMPs properties has not been achieved. Even less is known about the inﬂuence of the SMP topology or crosslinking method on their magnetic response. Thus, the goals of this project: (a) to determine equilibrium phase diagram and magnetic dynamic response of linear SMPs depending on the rigidity, varied from highly ﬂexible, polymer-like backbones to almost rod-like structures; (b) investigate the behaviour of ring-like SMPs in order to elucidate the contribution of magnetic component via comparing the results to that obtained for ring polymers; (c) for X- and Y-shaped SMPs to investigate the possibilities of phase separation.

Methods:

We will perform coarse-grained simulations using molecular dynamics with special approaches for (a) long-range magnetic interactions and (b) hydrodynamic interactions. The rigidity would be varied, using appropriate spring constants when crosslinking SMPs in silica [3,4].

Time frame:

Months 1-8: linear, X- and Y- single SMP in the ﬂow, the role of rigidity; months 9-12: same for ring-like SMP and polymer; months 12-18: Self-assembly and its impact on the dynamic response of linear, X- and YSMPs; months 18-30: Self-assembly as a function of SMPs rigidity; months 31-44: Self-assembly of ring-like SMPs in the ﬂow at high concentartion, comparison to the polymers; months 45-48 writing thesis and preparing the defence.

Participating DCAFM-faculty:

S. Kantorovich (PI), C. Likos (ring polymers), P. Ayala (carbon nanotubes), A. Bismarck (polymer nanocomposites).

[1] R. Dreyfus et al., Nature 437, 862-865, (2005), DOI: 10.1038/nature04090.
[2] J. Byrom et al., Langmuir 30, 9045-9052 (2014), DOI: 10.1021/la5009939.
[3] P. A. Sánchez et al., Faraday Discuss. 186, 241-263 (2016), DOI: 10.1039/C5FD00133A.
[4] D. A. Rozhkov et al., Mol. Sim. 44, 507-515 (2018), DOI: 10.1080/08927022.2017.1378815.