A confocal microscopy study of micron-sized poly(N-isopropylacrylamide) microgel particles at the oil-water interface and anisotopic flattening of highly swollen microgel.
Klíčová slova
Abstraktní
OBJECTIVE
Responsive poly(N-isopropylacrylamide) microgel (PNIPAM microgel) stabilized Pickering emulsions were investigated in this study. A recent theoretical study of other researchers has suggested that large soft particles at the oil/water interface are less deformable than their small counterparts. Therefore, we expected that our micron-sized microgel particles might not significantly deform at the oil/water interface.
METHODS
We applied confocal laser scanning microscopy (CLSM) to examine the structure of soft PNIPAM-based microgel particles at the decane-water interface in a microgel-stabilized emulsion. Using micron-sized microgel particles with better labelling techniques, we could compensate the weakness in resolution of using CLSM. Seven PNIPAM-based microgel samples with various softness values and morphologies were examined at different pH values.
RESULTS
Our results demonstrate that the deformation of ordinary micron-sized microgel samples was not significant if they were not in the pH-swollen state. Nevertheless, the soft, pH-swollen microgel particles exhibited anisotropic deformation at the decane-water interface. Such flattening was not reported in previous studies. The studies of microgel particles at the oil-water interface with different imaging techniques and their comparison are valuable to help to elucidate the particles' roles in stabilizing the Pickering emulsions.
