Weak polyelectrolyte brushes

Abstract

Grafted weak polyelectrolytes (brushes) change shape with pH and/or added salt. This gives them “smart” properties that can be used in adhesion, lubrication, or actuation.

Precision polymer nanofibers with a responsive polyelectrolyte corona designed as a modular, functionalizable nanomedicine platform

“…Polyelectrolyte materials have found numerous applications both inside and outside biology, from use in water treatment and purification, 1 the controlled wetting of surfaces 2 or as ion exchange membranes in fuel cells, 3 to uses in medical implant coatings, 4 nucleic acid delivery, 5 antimicrobials 6 and bioelec-tronics. 7 In particular, they have promising lubrication properties that are useful for anti-fouling coatings, 8 such as those used for medical implants, 4 whilst their bioadhesion properties allow them to encapsulate cells for drug delivery, 9 as well as making them potentially useful antimicrobial agents. 6 One of the most promising applications of polyelectrolytes is the delivery of therapeutic nucleic acids, which remains a key challenge that hampers the development of new treatments for a plethora of diseases from COVID-19 to cancer.…”

Machine learning enabled quantification of the hydrogen bonds inside the polyelectrolyte brush layer probed using all-atom molecular dynamics simulations

“…Polyelectrolyte (PE) brushes, which refer to charged PE chains densely grafted to a surface, have received wide attention [1][2][3][4][5][6][7][8] owing to their extensive applications in a variety of disciplines including fabrication of ionic diodes, 9 ion and biosensors, 10,11 and current rectifiers, 12 energy conversion, [13][14][15] targeted drug delivery, 16 water harvesting, 17 oil treatment, 18 and many more. For all these applications, the responsiveness of the PE molecules to the environmental stimuli (e.g., pH and ion concentration of the aqueous medium) becomes critical.…”

Weak Polyelectrolytes as Nanoarchitectonic Design Tools for Functional Materials: A Review of Recent Achievements

“…Finally, when the valency of counter-ions is changed from monovalent to multivalent, intramolecular electrostatic crosslinking leads to further conformational transitions ( Scheme 1 ) [ 7 , 8 ]. It is thus not surprising that a wide range of synthetic and natural weak polyelectrolytes have been developed ( Table 1 ), while their properties as reversible polyacids/bases [ 9 , 10 ], complexing agents [ 11 , 12 ], and self-assembling units in functional systems [ 13 , 14 , 15 , 16 ] have been very actively investigated. It is worth noting that the apparent pKa of weak polyelectrolytes, measured by pH titration, conductimetry, and infrared spectroscopy, varies notably depending on experimental parameters such as their molecular weight, conformation, confinement, and complexation [ 17 , 18 , 19 , 20 ].…”

“…Polymer brushes are extensively used as colloidal stabilizers, lubricating layers, and drug delivery systems [ 35 ]. In that respect, elaborating brushes based on weak polyelectrolytes is generally aimed at developing stimuli-responsive systems, and was reviewed recently [ 15 ]. Grafting-from approaches, where polyelectrolyte chains grow in situ from their surface anchoring points, typically offering higher grafting densities than approaches where pre-synthesized polyelectrolyte chains are used [ 36 , 37 ], have therefore been developed by using several radical polymerization technics [ 35 ].…”