title: Polyelectrolyte brush amplified electroactuation of microcantilevers.
abstract: This paper describes the electroactuation of microcantilevers coated on one side with cationic polyelectrolyte brushes. We observed very strong cantilever deflection by alternating the potential on the cantilever between +0.5 and -0.5 V at frequencies up to 0.25 Hz. The actuation resulted from significant increases in the expansive stresses in the polymer brush layer at both negative and positive potentials. However, the deflection at negative bias was significantly larger. We have developed a theoretical framework that correlates conformational changes of the polymer chains in the brush layer with the reorganization of ions due to the potential bias. The model predicts a strong increase in the polymer volume fraction, close to the interface, which results in large expansive stresses that bend the cantilever at negative potentials. The model also predicts that the actuation responds much stronger to negative potentials than positive potentials, as observed in the experiments.
authors.affiliation: Melville Laboratory for Polymer Synthesis, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW United Kingdom.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhou
authors.forename: P Maarten
authors.initials: PM
authors.lastname: Biesheuvel
authors.forename: Eun-Young
authors.initials: EY
authors.lastname: Choi
authors.forename: Wenmiao
authors.initials: W
authors.lastname: Shu
authors.forename: Rosa
authors.initials: R
authors.lastname: Poetes
authors.forename: Ullrich
authors.initials: U
authors.lastname: Steiner
authors.forename: Wilhelm T S
authors.initials: WT
authors.lastname: Huck
mesh_terms: D017076:Computer-Aided Design; D003460:Crystallization / Q000379:methods; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004573:Electrolytes / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008422:Materials Testing; D009038:Motion; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D010316:Particle Size; D014159:Transducers
chemical_list: D004573:Electrolytes