EAGER: Exploring the role of polymer thermodynamics in the formation of patches on polymer-core-shell particles

George Mason University, Fairfax VA

Investigators

Abstract

1348112 PI: Morales This EAGER award supports a research plan for exploring the role of polymer thermodynamics in the formation of patches on polymeric cores. The PI has recently discovered the formation of a new class of patchy particles with a unique core-shell structure consisting of a hollow hydrophobic polymeric core and a patchy surface made of single or dual lipid-polymer based patches independently distributed and oriented on the surface of the core. The mechanism of patch formation is not yet understood. The formation of patches on polymeric cores was a somewhat unexpected phenomenon in light of the fact that amine groups, having a positive charge at neutral pH, were expected to repel each other rather than form clusters or patches. It is hypothesized that the patch formation phenomenon observed experimentally is due to the polymer phase segregation phenomenon. A determination of the driving forces involved in the formation process is necessary to gain a deep understanding of the process. This exploratory research aims to investigate the role that: 1) thermodynamic interactions such as polymer-solvent and polymer polymer-solvent play in the phase separation phenomenon and 2) the interfacial tension plays in the phase separation phenomenon. . At the fundamental level, this proposal will advance the self-assembly field by adding new knowledge to the phase separation phenomenon. In the past, the phase separation phenomenon has been observed, reported and discussed in systems such as binary self-assembly monolayers (SAM) of n-alkanethiols on gold, surfactant coated nanoparticles and surfactant-coated substrates, but not on the surface of polymeric particles. The PI is the first to report that the phase separation phenomenon also occurs in the presence of two different lipid-PEGylated functional groups. The full understanding of this phenomenon is critically relevant for the interaction between patchy particles and biological entities such as proteins, cells and tissues. These patchy particles have potential applications in drug and vaccine delivery.