TY  - GEN
A1  - Werner, Peter
A1  - Münzberg, Marvin
A1  - Hass, Roland
A1  - Reich, Oliver
T1  - Process analytical approaches for the coil-to-globule transition of poly(N-isopropylacrylamide) in a concentrated aqueous suspension
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - The coil-to-globule transition of poly(N-isopropylacrylamide) (PNIPAM) microgel particles suspended in water has been investigated in situ as a function of heating and cooling rate with four optical process analytical technologies (PAT), sensitive to structural changes of the polymer. Photon Density Wave (PDW) spectroscopy, Focused Beam Reflectance Measurements (FBRM), turbidity measurements, and Particle Vision Microscope (PVM) measurements are found to be powerful tools for the monitoring of the temperature-dependent transition of such thermo-responsive polymers. These in-line technologies allow for monitoring of either the reduced scattering coefficient and the absorption coefficient, the chord length distribution, the reflected intensities, or the relative backscatter index via in-process imaging, respectively. Varying heating and cooling rates result in rate-dependent lower critical solution temperatures (LCST), with different impact of cooling and heating. Particularly, the data obtained by PDW spectroscopy can be used to estimate the thermodynamic transition temperature of PNIPAM for infinitesimal heating or cooling rates. In addition, an inverse hysteresis and a reversible building of micrometer-sized agglomerates are observed for the PNIPAM transition process.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 944 
KW  - poly(N-isopropylacrylamide)
KW  - Photon Density Wave spectroscopy
KW  - Focused Beam Reflectance Measurement
KW  - turbidity measurement
KW  - Particle Vision Microscope measurement
KW  - rate-dependent lower critical solution temperature
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-431162
SN  - 1866-8372
IS  - 944
SP  - 807
EP  - 819
ER  -