Elucidating Interfacial Chain Conformation of Superhydrophilic Polymer Brushes by Vibrational Sum Frequency Generation Spectroscopy.
Langmuir
; 38(48): 14704-14711, 2022 Dec 06.
Article
en En
| MEDLINE
| ID: mdl-36394829
ABSTRACT
Surface-tethered macromolecules (polymer brushes) are a potent means to modify surfaces with stimuli-responsive properties while avoiding delamination problems. This vibrational sum frequency generation spectroscopy study describes how the conformation of hydrophilic polymer brushes changes in response to environmental conditions, that is, changes in humidity (in air) and upon exposure to liquid water. Three hydrophilic brushes were prepared on silicon oxide surfaces by surface-initiated reversible deactivation radical polymerization of cationic (quaternary ammonium), anionic (sulfonate), and zwitterionic (containing both) monomers. The average tilt angle of methyl groups was analyzed and used to deduce the chain conformations of the polymer brushes. In air, the brush films absorb water and swell with increasing humidity. This is accompanied by the rotation of interfacial polymer chains. The degree of water uptake and chain conformation vary with the nature of the charged hydrophilic moieties. The hydrophilic polymer brush surfaces appear to remain relatively dry except in near-condensation conditions. In water, the quaternary ammonium groups of cationic and zwitterionic brushes are aligned nearly parallel to the surface. The anionic brush chains appear to assume nearly random conformations in water.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
Langmuir
Asunto de la revista:
QUIMICA
Año:
2022
Tipo del documento:
Article
País de afiliación:
Estados Unidos