Hedgehog, Chamomile and Multipetal Polymeric Structures on the Nanoparticle Surface: Theoretical Insights

Abstract

An analytical theory describing the variety of different morphological structures that spontaneously self-assemble in layers of amphiphilic homopolymers tightly grafted to spherical nanoparticle is proposed. For this purpose, the following structures were identified and outlined: hedgehogs, in which macromolecules are combined into cylindrical aggregates; chamomile, when cylindrical aggregates are connected by their ends into loops; multipetal structure with macromolecules self-assembling into thin lamellae; and unstructured, swollen and uniformly compacted shells. The results are presented in the form of state diagrams and serve as a basis for the directional design of the surface pattern by varying system parameters (particle radius, grafting density and degree of polymerization) and solvent properties (quality and selectivity).

Hedgehog, Chamomile, and Multipetal Polymeric Structures on the Nanoparticle Surface: Computer Modelling

“…Each chain is grafted onto the particle surface by fixing the A bead of its first monomeric unit to the surface. To distribute grafting points uniformly, they are placed at the nodes of the Fibonacci lattice (described in detail in [ 56 ]). The nanoparticle is immersed into a solvent, which is athermal for the nanoparticle and selective for the grafted amphiphilic homopolymer: it is athermal for B pendants and poor for the A main chain.…”

“…In this context, spherical nanoparticles coated with an amphiphilic homopolymer [ 48 , 49 , 56 ] can serve as a coarse-grained model to determine the conditions for the formation of certain structures and to identify areas of stability. In a computer experiment, we observed both divergent cylindrical filaments and lamellae and named them a hedgehog and multipetaler, respectively.…”

“…Recent theoretical calculations have shown that under some conditions, the rearrangement between hedgehog and multipetal structures is possible with no crucial change in the quality of the solvent or its selectivity [ 56 ]. This gives broad prospects for precise design of MFNCs and for determining the conditions for their rapid and effective reconstruction.…”