Effect of Architecture and Topology on the Self-Assembly of Polymer-Grafted Nanoparticles

We study the effect of the architecture and topology of polymer-grafted nanoparticle species on their structure, phase behavior, and scaling behavior. Using integral equation theory, we study three different architectures of chemically isotropic polymer-grafted nano -particle species: singly-grafted nanoparticles, doubly-grafted nano -particles, and ring-grafted nanoparticles. We compare the phase behavior of these three architectures with that of polymer-linked nanoparticles [Tripathy, M. Soft Matter2017, 13, 2475-2482]. These polymer-grafted nanoparticle species undergo an entropy-driven transition from a disordered fluid phase to microphase-separated structures with alternating polymer-rich and nanoparticle-rich domains. Species with larger nanoparticles and longer polymer chains show higher tendency toward microphase separation. However, as the chain lengths decrease, the microphase transition boundaries of grafted nanoparticles with varying nanoparticle diameters converge to a unique point on the phase diagram. This behavior is noted for all four architectures under consideration. All the sparsely-grafted species with different architectures and topologies exhibit qualitatively similar spinodal phase behavior. However, the scaling behavior of the length scale of self-assembly depends on the topology of the polymer-grafted nanoparticles. While the scaling exponent is same for the three linear topologies under consideration (singly-grafted nanoparticles, doubly-grafted nanoparticles, and polymer-linked nanoparticles), it is markedly different for the ring topology.

Automated summary

This study investigates the effect of architecture and topology of polymer-grafted nanoparticle species on their structure, phase behavior, and scaling behavior. The phase behavior of these species undergoes an entropy-driven transition from a disordered fluid phase to microphase separation. The scaling behavior of self-assembly depends on the topology of the polymer-grafted nanoparticles.