In situ dissolution and swelling of confined lamellar polymer crystals through exposure to humid air

Abstract: Using a hydrophobic-hydrophilic poly(styrene)-b-poly(ethylene oxide) diblock copolymer (PS-b-PEO), we formed sandwich-like micron-sized thin platelets via crystallization in solution. These platelets consisted of a crystalline PEO lamella confined between two glassy PS layers and were deposited on a solid substrate. Using in-situ optical microscopy, we followed the temporal and spatial changes in thickness and morphology of these sandwich-like platelets induced by exposure to humid air. As water is a good solvent for PEO but a nonsolvent for PS, we observed first the dissolution of the confined crystalline PEO layers characterized by sharp dissolution front propagating at an almost constant velocity as expected for case II diffusion into a solid. The resulting hydrated PEO brushes absorbed further water until equilibration of the respective chemical potentials, accompanied by a change from a planar to a dome-shaped morphology which could be fully reversed by exposure to dry air. Repeated swelling/de-swelling cycles demonstrated stability and reproducibility of these developments taking place at distinctly different transport rates. We discuss the underlying processes of water permeation into and efflux from the PEO layers

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Edition: [Manuskript-Version]
• Language: Englisch

Classification and Topics

• Keyword: Diblockcopolymere

Contributors, Places and Time

• Event: Veröffentlichung
• (where): Freiburg
• (who): Universität
• (when): 2022
• Creator: Bessif, Brahim ; Pfohl, Thomas ; Heck, Barbara ; AlShetwi, Yaser Abdulaziz ; Khechine, Emna ; Xu, Jun ; Reiter, Günter

Further information

• DOI: 10.6094/UNIFR/228227
• URN: urn:nbn:de:bsz:25-freidok-2282274
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 25.03.2025, 1:47 PM CET