Jump to main content
Jump to site search
PLANNED MAINTENANCE Close the message box

Scheduled maintenance upgrade on Thursday 4th of May 2017 from 8.00am to 9.00am (BST).

During this time our websites will be offline temporarily. If you have any questions please use the feedback button on this page. We apologise for any inconvenience this might cause and thank you for your patience.


Issue 1, 2017
Previous Article Next Article

Thermoresponsive microgels at the air–water interface: the impact of the swelling state on interfacial conformation

Author affiliations

Abstract

Poly(N-vinylcaprolactam) (PVCL) is a new temperature-responsive type of polymer microgel with improved biocompatibility as compared to more commonly used poly(N-isopropylacrylamide) (PNIPAM). Both polymers swell at low temperatures and collapse at high ones, showing a volume phase transition temperature (VPTT) around the physiological temperature. Exploring the interfacial characteristics of thermoresponsive microgels is important due to their potential application in emulsion based systems with tailored stabilities and controlled degradation profiles. In this work, we study the properties of charged PVCL particles at the air–water interface by a combination of adsorption, dilatational rheology and Langmuir monolayers. Although PVCL particles adsorb spontaneously at the air–water interface in both, swollen and collapsed conformations, the interfacial properties show significant differences depending on the swelling state. In particular, the total amount of adsorbed microgels and the rigidity of the monolayer increase as the temperature increases above the VPTT, which is connected to the more compact morphology of the microgels in this regime. Dilatational rheology data show the formation of a very loose adsorbed layer with low cohesivity. In addition, collapsed microgels yield a continuous increase of the surface pressure, whereas swollen microgels show a phase transition at intermediate compressions caused by the deformation of the loose external polymer shell of the particles. We also provide a qualitative interpretation for the surface pressure behavior in terms of microgel–microgel effective pair potentials, and correlate our experimental findings to recent rescaling models that take into account the importance of the internal polymer degrees of freedom in the rearrangement of the conformation of the microgel particles at the interface.

Graphical abstract: Thermoresponsive microgels at the air–water interface: the impact of the swelling state on interfacial conformation

Back to tab navigation
Please wait while Download options loads

Publication details

The article was received on 16 Jun 2016, accepted on 11 Jul 2016 and first published on 11 Jul 2016


Article type: Paper
DOI: 10.1039/C6SM01375A
Citation: Soft Matter, 2017,13, 230-238
  •   Request permissions

    Thermoresponsive microgels at the air–water interface: the impact of the swelling state on interfacial conformation

    J. Maldonado-Valderrama, T. del Castillo-Santaella, I. Adroher-Benítez, A. Moncho-Jordá and A. Martín-Molina, Soft Matter, 2017, 13, 230
    DOI: 10.1039/C6SM01375A

Search articles by author