Entropic death of nonpatterned and nanopatterned polyelectrolyte brushes. Issue 12 (23rd April 2019)

• Record Type: Journal Article
• Authors: Menzel, Matthias; Chen, Wei‐Liang; Simancas, Kimberly; Xu, Hong; Prucker, Oswald; Ober, Christopher K.; Rühe, Jürgen
• Is Part Of: Journal of polymer science. Volume 57:Issue 12(2019)
• Page Start: 1283
• Page End: 1295
• Publication Date: 2019-04-23
• Subjects: entanglements -- entropic death -- nanopatterned brush -- osmotic shock -- patterning -- polymer brush -- polyelectrolyte brush -- stability stabilization -- stimuli‐sensitive polymers -- surfaces -- thin films; 547
• DOI: 10.1002/pola.29384
• Languages: English
• ISSNs: 0887-624X

Abstract

ABSTRACT: The stability of nonpatterned and nanopatterned strong polyelectrolyte brushes (PEBs) is studied as a function of both brush character and the properties of a contacting liquid. High‐molecular‐weight PEBs of poly(4‐methyl vinylpyridinium iodide) (PMeVP) are synthesized using surface‐initiated radical‐chain polymerization. Nanopatterned brushes (NPBs) line with pattern sizes ranging from 50 to 200 nm are generated by patterning the initiator layer using deep‐ultraviolet photolithography followed by brush growth initiated from the patterned layer. Homogeneous PEBs with different degrees of charging and grafting densities are exposed to water and salt solutions with different temperatures for different periods. The degradation is monitored through dry‐state ellipsometry and atomic force microscopy measurements. Enhanced degrafting for more strongly swollen polymer brushes can be observed in agreement with an "entropic spring" model. Based on the results of the nonpatterned brushes, the NPBs are exposed to water at different temperatures and external salt content for varying periods of time. Counterintuitively, the NPBs show increased degrafting for smaller patterns, which is attributed to different polymer chain dynamics for nanobrushes and microbrushes. We investigate the influence of thermodynamic and kinetic parameters on the stability of (nanopatterned) PEBs and discuss the role of entanglements and formation of complexes in such films. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1283–1295 Abstract : The stability of high‐molecular‐weight nonpatterned and nanopatterned strong polyelectrolyte brushes (PEBs) is studied under different conditions. Nonpatterned brushes show degrafting in agreement with an "entropic spring" model. Nanopatterned brushes show degrafting counterintuitively to the model, which is attributed to polymer chain dynamics. The authors investigate the influence of thermodynamic and kinetic parameters on the stability of PEBs and discuss the role of entanglements and formation of complexes in such films.