@misc{10481/108650,
year = {2026},
month = {3},
url = {https://hdl.handle.net/10481/108650},
abstract = {Hypothesis: Biocompatible microgels based on oligo(ethylene glycol) (OEG-based microgels) represent a new generation of microgels designed for biomedical applications. OEG-based microgels undergo swelling or collapse in bulk in response to external stimuli such as temperature or pH. Gaining a deeper understanding of the surface properties of OEG-based microgels is essential for the proper development of stimuli-responsive emulsions and foams.
Methodology: Combination of colloidal and surface experimental techniques; hydrodynamic diameter, electrokinetic, analysis of Langmuir and Gibbs monolayers with in-situ microscopy, Atomic Force Microscopy and dilatational rheology in linear and non-linear regime provide new insights into the surface conformation of OEG-based microgels.
Results: Swelling and electrokinetic response of OEG-based microgels are initially examined as a function of pH and temperature to stablish the Volume Phase Transition Temperature (VPTT) at various pHs. Langmuir monolayers of OEG-based microgels show a “fried-egg” structure typical of thermoresponsive microgels, below and above the VPTT, exhibiting similar surface coverage but protruding slightly further into the subphase in collapsed state. Gibbs monolayers of OEG-based microgels reveal that collapsed OEG-based microgels diffuse and adsorb faster onto the surface but rearrange similarly to swollen OEG-based microgels. Finally, the slightly greater protrusion of collapsed OEG-based microgels ultimately determines their dilatational behaviour in both linear and non-linear regimes.
Conclusions: Surface conformation of OEG-based microgels show very subtle stimuli responsiveness, which in principle, should not compromise their use as emulsion stabilizers. However, they may need to be considered for fine applications of OEG-based microgels as stabilizers in the rational development of stimuli-responsive foams and emulsions.},
organization = {Consejería de Universidad, Investigación e Innovación and by ERDF Andalusia Program 2021-2027 - (C-EXP-187-UGR23) and (C-ING-208-UGR23)},
organization = {MICIU/AEI/10.13039/501100011033 and ERDF, a way of making Europe - (PID2023-149387OB-I00) (PID2020-116615RA-I00)},
organization = {EMERGIA -  (EMC21_00008)},
organization = {COST Action - (INFOTECH-DATA CA24145)},
organization = {Universidad de Granada / CBUA - open access charge},
publisher = {Elsevier},
keywords = {Oligo (ethylene glycol)},
keywords = {Microgels},
keywords = {surface tension},
title = {Surface characterisation of thermoresponsive microgels based on oligo(ethylene glycol): Adsorption kinetics, dilatational rheology and monolayers},
doi = {10.1016/j.jcis.2025.139522},
author = {Aguirre, Garbiñe and Quirosa Mancilla, J. and Cara Galdeano, Carmen and Navarro Arrebola, Iván and Rubio Andrés, Antonio and Fernández Rodríguez, Miguel Ángel and Billon, Laurent and Martín Molina, Alberto and Maldonado Valderrama, Julia},
}