Responsive Polyelectrolyte Brushes in Applications: Functions, Stimuli, and Design Considerations

Polyelectrolyte brushes are stimulus-responsive coatings that change surface properties such as friction, adhesion, and interaction with biomolecules. Brush coatings are becoming increasingly available with improving synthesis and fabrication methods, but their use in real-world applications is trailing behind. With their stimulus-controlled properties, brushes can fulfill a variety of functions when they are applied in a broad spectrum of use cases ranging from tunable lubrication to ionic current rectification. In this review, summarizes the functional roles polyelectrolyte brushes can play in applications by affecting the mechanical, molecular, and electrical properties of surfaces; the main stimuli that are used to exploit the responsiveness of these coatings are discussed; and design considerations to choose an initial brush when designing systems for new applications are provided. This review concludes with a short outlook on the outstanding challenges and opportunities for applying stimulus-responsive polyelectrolyte brushes.