Influence of particle size on the thermoresponsive and rheological properties of aqueous poly(N-isopropylacrylamide) colloidal suspensions

• Published in: Bulletin of materials science Vol. 43; no. 1; p. 182
• Main Authors: Misra, Chandeshwar, Behera, Sanjay Kumar, Bandyopadhyay, Ranjini
• Format: Journal Article
• Language: English
• Published: Bangalore Indian Academy of Sciences 01-12-2020; Springer Nature B.V
• Subjects: Behavior; Chemistry and Materials Science; Colloids; Emulsion polymerization; Engineering; Free energy; Hydrogels; Materials Science; Particle size; Phase transitions; Photon correlation spectroscopy; Polyisopropyl acrylamide; Rheological properties; Rheology; Scanning electron microscopy; Sodium dodecyl sulfate; Soft Materials; Surfactants; Swelling ratio; crosslinking density; Thermoresponsivity; swelling ratio
• ISSN: 0250-4707; 0973-7669
• DOI: 10.1007/s12034-020-02157-9

Thermoresponsive poly(
N
-isopropylacrylamide) (PNIPAM) particles of different sizes are synthesized by varying the concentration of sodium dodecyl sulphate (SDS) in a one-pot method. The sizes, size polydispersities and the thermoresponsivity of the PNIPAM particles are characterized by using dynamic light scattering and scanning electron microscopy. It is observed that the sizes of these particles decrease with increase in SDS concentration. Swelling ratios of PNIPAM particles measured from the thermoresponsive curves are observed to increase with decrease in particle size. This observation is understood by minimizing the Helmholtz free energy of the system with respect to the swelling ratio of the particles. Finally, the dynamics of these particles in jammed aqueous suspensions are investigated by performing rheological measurements.