Probing Temperature Responsivity of Microgels and Its Interplay with a Solid Surface by Super-Resolution Microscopy...

Area of Science:

• Colloid and Polymer Science
• Surface Science
• Advanced Microscopy Techniques

Background:

• Super-resolution microscopy enables nanoscale investigation of colloidal and polymeric systems like microgels.
• Monitoring microgel behavior in response to temperature changes *in situ* is crucial for understanding their properties.
• Particle-environment interactions, especially with substrates, significantly influence experimental outcomes.

Purpose of the Study:

• To investigate the influence of hydrophilic and hydrophobic surfaces on microgel volume phase transitions using super-resolution microscopy and simulations.
• To understand the role of surface interactions in microgel structural changes with varying temperatures.
• To establish a high-resolution monitoring platform for complex macromolecular and nanocomplex systems.

Main Methods:

• Direct Stochastic Optical Reconstruction Microscopy (dSTORM) for high-resolution imaging of individual microgels.
• Advanced coarse-grained molecular dynamics simulations to model microgel behavior.
• Comparative analysis of microgels on hydrophilic versus hydrophobic substrates under temperature changes.

Main Results:

• Microgels on hydrophilic surfaces maintained their structure, with density profiles matching bulk simulations.
• Microgels on hydrophobic surfaces exhibited spreading at the interface.
• A competition between monomer-monomer and monomer-surface hydrophobic interactions was observed at higher temperatures on hydrophobic surfaces.

Conclusions:

• Surface properties critically affect microgel behavior during temperature-induced transitions.
• The combination of dSTORM and molecular dynamics provides a robust platform for studying microgel-surface interactions.
• This approach can be extended to investigate complex macromolecules and temperature-controlled drug delivery systems.