Simulation of reversible, electrostatically linked Modelnetworks

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Amphiphilic cone networks (ACN) are networks consisting of hydrophilic and hydrophobic polymer building blocks, forming complex structures with interesting tunable properties. In our proposal, ACNs consisting of reversible-ionically linked building blocks (e.g. star polymers) are of particular interest, since for these systems network properties can be changed by external parameters such as salt concentration and pH (in the case of weak charges on the building blocks). Those ACNs have hardly been explored so far, but because of their interesting tunable properties, these networks have numerous potential applications, for example, as cell substrates. In this project, molecular dynamics and Monte Carlo simulations of coarse-grained bead-spring polymer models will be used to gain insights into the microscopic structure as well as the dynamics of reversible (built from ionic four-arm star polymers) and covalent-reversible (i.e. already partially pre-crosslinked) ACN. First, the network formation as well as the equilibrium state of the fully reversible four-arm star systems will be characterized as a function of different parameters such as pH, salt concentration, block length, and for different star architectures. Subsequently, the partitioning of model proteins between a reservoir and the networks will be investigated. These proteins will be represented as "weakly charged patchy particles" and we will extend our G-RxMC method to be able to simulate those. In the next step, we will investigate dynamic properties such as the transport of probe particles in the networks, using the protein models from the previous studies. To account for hydrodynamic interactions, we will couple the probe particles as well as polymers and ions to a lattice Boltzmann fluid. In the third work package, the previous investigations will be repeated for already pre-crosslinked covalent-reversible hybrid networks. Finally, thin hybrid networks fixed on a surface will be investigated with respect to their swelling behavior and mechanical properties and compared with bulk system properties.