Microgels are highly sensitive colloidal polymer networks that dynamically respond to environmental changes by transitioning between a swollen, solvent-rich state and a dense, collapsed state.
This research focuses on star microgels, a particular microgel architecture that distinguishes itself from regular microgels through its star-like, branched structure, where polymeric chains radiate outward from a central, densely cross-linked core. This structure is of interest for two main reasons: first, star-shaped architectures hold potential for diverse applications, as they can be functionalized for specific uses; second, they represent a relatively unexplored area in microgel research.
This structure is expected to sharpen the microgel’s volume phase transition and increase its swelling capacity even at high crosslinker concentrations, setting it apart from standard microgels and potentially enhancing its responsiveness to temperature changes.
We addressed these hypotheses by presenting an in silico synthesis model for star microgels and employing molecular dynamics simulations to investigate their structural properties, focusing on the thermoresponsive behavior of the samples. The research is divided into two main parts: first, we generated and simulated simplified star polymeric systems; afterwards, we developed a model to synthesize star microgels in silico through a self-assembly approach and performed simulations on these systems.
Results are compared to experiments in which similar sharp volume transitions in microgels have been achieved by varying the crosslinkers used during synthesis, based on their reaction rates: the idea is that rapid crosslinker reactivity forms a dense core, while slowerreacting monomers create radial chains around it.
This study reveals the connection between the distinctive structure of star microgels and their properties, offering a perspective that may guide better synthetic control and future applications of star-like microgel architectures.