The synthesis of nanoparticle building blocks functionalized with specifically designed oligonucleotides [1] has opened new possibilities for the assembly of networked materials. The DNA-type interactions offer selectivity and sensitivity that will play an important role in the self-assembly of these particles. These properties allow us to control the inter-particle interactions that will lead to the construction of the desired supra-molecular structures. We present a molecular dynamics simulation study of a simple DNA-dendrimer model designed [2] to capture the basic characteristics of the biological interactions. Exploring a large set of state points [3], we follow the progressive formation of a percolating large-scale network whose connectivity can be described by random percolation theory. We identify the relative regions of network formation and kinetic arrest versus phase separation. The location of the two-phase region can be interpreted in the same framework as reduced valency models. This correspondence provides guidelines for designing stable, equilibrium self-assembled low-density networks. Finally, we demonstrate a relation between bonding and dynamics, by showing that the temperature dependence of the diffusion constant is controlled by the number of fully un-bonded dendrimers.

The design of an effective inter-particle potential for this family of dendrimers is discussed. The results obtained with this effective potential are compared with the results of the full-system.

[1] Mirkin C A, Letsinger R L, Mucic R C and Storhoff J J Nature 382 607–9 (2006)

[2] Starr F.W. and Sciortino F.,J. Phys.: Condens. Matter 18 L347–L353 (2006).

[3] Largo J., Starr F.W. and Sciortino F. Langmuir (2007).