TY - JOUR
T1 - Comparison of the Swelling Behavior of Poly(N-Isopropylacrylamide) and Poly(N-Vinylisobutyramide) Thin Films under Water Vapor Exposure
AU - Le Dû, Morgan P.
AU - Reitenbach, Julija
AU - Kosbahn, David P.
AU - Spanier, Lukas V.
AU - Cubitt, Robert
AU - Henschel, Cristiane
AU - Laschewsky, André
AU - Papadakis, Christine M.
AU - Müller-Buschbaum, Peter
N1 - Publisher Copyright:
© 2025 The Authors. Published by American Chemical Society.
PY - 2025
Y1 - 2025
N2 - Poly(N-isopropylacrylamide) (PNIPAM) is known for exhibiting lower critical solution temperature behavior in water. A structural isomer of PNIPAM, the likewise LCST-type polymer poly(N-vinylisobutyramide) (PNVIBAM), is compared to PNIPAM in a thin film with respect to their swelling behaviors and water uptake kinetics in a humid atmosphere. Based on spectral reflectance, Fourier-transform infrared (FT-IR) spectroscopy, and time-of-flight neutron reflectometry, the amount and kinetics of uptaken water and its distribution inside the films correlate with molecular changes. It is observed that PNVIBAM swells less than PNIPAM. The FT-IR signals reveal a lower water affinity for PNVIBAM than for PNIPAM and larger hydrophobic clathrates in PNVIBAM, which hinders the introduction of water. Additionally, N2-dried PNIPAM films still contain primary water, whereas PNVIBAM can be fully dried. The first step of water uptake of the main layer describes a filling of the free volume, reaching a water content of 3.8% in PNVIBAM and 6% in PNIPAM.
AB - Poly(N-isopropylacrylamide) (PNIPAM) is known for exhibiting lower critical solution temperature behavior in water. A structural isomer of PNIPAM, the likewise LCST-type polymer poly(N-vinylisobutyramide) (PNVIBAM), is compared to PNIPAM in a thin film with respect to their swelling behaviors and water uptake kinetics in a humid atmosphere. Based on spectral reflectance, Fourier-transform infrared (FT-IR) spectroscopy, and time-of-flight neutron reflectometry, the amount and kinetics of uptaken water and its distribution inside the films correlate with molecular changes. It is observed that PNVIBAM swells less than PNIPAM. The FT-IR signals reveal a lower water affinity for PNVIBAM than for PNIPAM and larger hydrophobic clathrates in PNVIBAM, which hinders the introduction of water. Additionally, N2-dried PNIPAM films still contain primary water, whereas PNVIBAM can be fully dried. The first step of water uptake of the main layer describes a filling of the free volume, reaching a water content of 3.8% in PNVIBAM and 6% in PNIPAM.
UR - http://www.scopus.com/inward/record.url?scp=85214366244&partnerID=8YFLogxK
U2 - 10.1021/acs.macromol.4c02802
DO - 10.1021/acs.macromol.4c02802
M3 - Article
AN - SCOPUS:85214366244
SN - 0024-9297
JO - Macromolecules
JF - Macromolecules
ER -