DOI > 10.5291/ILL-DATA.9-11-1695

This proposal is publicly available since 10/11/2019

Title

Kinetics of the pressure-induced coil-to-globule transition of PNIPAM microgels

Abstract

PNIPAM is a thermoresponsive microgel which is interesting due to its lower critical solution temperature (LCST) which is located close to the temperature of the human body. There, PNIPAM undergoes a coil-to-globule transition which is connected to a dramatic change of volume. It is possible to deswell the particles applying pressure. However, the influence of pressure on the coil-to-globule transition and especially the kinetics of the pressure-induced structural changes have not been studied systematically so far. By performing DLS studies as a function of temperature and pressure we found that the LCST increases by approximately 2 K applying a pressure of 300 bar. In preliminary SANS measurements performed at the D22 we were able to confirm these findings. The next step would be the investigation of the kinetics of the swelling and deswelling behaviour upon a change of hydrostatic pressure. In order to conduct such kinetic studies we propose to perform time-resolved SANS measurements using our newly designed stroboscopic high pressure SANS-cell, which provides adjustable pressure cycles. Thereby the pressure can be varied between 1-300 bar with a maximum frequency of 10 Hz.

Experimental Report

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Data Citation

The recommended format for citing this dataset in a research publication is in the following format:

PUETZ Yvonne; GRASSBERGER Lena; HARBAUER Carola; LINDNER Peter; LUELSDORF Stefan; PORCAR Lionel; SCHWEINS Ralf; SOTTMANN Thomas; SOTTMANN DIANA and STREY Reinhard. (2014). Kinetics of the pressure-induced coil-to-globule transition of PNIPAM microgels. Institut Laue-Langevin (ILL) doi:10.5291/ILL-DATA.9-11-1695

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Metadata

Experiment Parameters

  • Environment temperature

    290-320 Kelvin
  • Experiment energy

    6 A
  • Experiment moment

    0.003-0.4 A^-1

Sample Parameters

  • Formula

    • Poly(N-isopropylacrylamid)