Control of Polymer Brush Morphology, Rheology, and Protein Repulsion by Hydrogen Bond Complexation
Journal article, 2021

Polymer brushes are widely used to alter the properties of interfaces. In particular, poly(ethylene glycol) (PEG) and similar polymers can make surfaces inert toward biomolecular adsorption. Neutral hydrophilic brushes are normally considered to have static properties at a given temperature. As an example, PEG is not responsive to pH or ionic strength. Here we show that, by simply introducing a polymeric acid such as poly(methacrylic acid) (PMAA), the highly hydrated brush barrier can change its properties entirely. This is caused by multivalent hydrogen bonds in an extremely pH-sensitive process. Remarkably, it is sufficient to reduce the pH to 5 for complexation to occur at the interface, which is two units higher than in the corresponding bulk systems. Below this critical pH, PMAA starts to bind to PEG in large amounts (comparable to the PEG amount), causing the brush to gradually compact and dehydrate. The brush also undergoes major rheology changes, from viscoelastic to rigid. Furthermore, the protein repelling ability of PEG is lost after reaching a threshold in the amount of PMAA bound. The changes in brush properties are tunable and become more pronounced when more PMAA is bound. The initial brush state is fully recovered when releasing PMAA by returning to physiological pH. Our findings are relevant for many applications involving functional interfaces, such as capture-release of biomolecules.

Author

John Andersson

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Gustav Ferrand-Drake Del Castillo

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Pierluigi Bilotto

Vienna University of Technology

Fredrik Höök

Chalmers, Physics, Nano and Biophysics

Markus Valtiner

Vienna University of Technology

Andreas Dahlin

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Langmuir

07437463 (ISSN) 15205827 (eISSN)

Vol. 37 16 4943-4952

SIMONANO (Single Molecule Analysis in Nanoscale Reaction)

Familjen Erling-Perssons stiftelse (SIMONANOStartingGrantADahlin), 2018-02-01 -- 2019-12-31.

Subject Categories

Polymer Chemistry

Physical Chemistry

Polymer Technologies

DOI

10.1021/acs.langmuir.1c00271

More information

Latest update

8/17/2021