title: Graphene/elastomer composite-based photo-thermal nanopositioners.
abstract: The addition of nanomaterials to polymers can result not only in significant material property improvements, but also assist in creating entirely new composite functionalities. By dispersing graphene nanoplatelets (GNPs) within a polydimethylsiloxane matrix, we show that efficient light absorption by GNPs and subsequent energy transduction to the polymeric chains can be used to controllably produce significant amounts of motion through entropic elasticity of the pre-strained composite. Using dual actuators, a two-axis sub-micron resolution stage was developed, and allowed for two-axis photo-thermal positioning (~100 μm per axis) with 120 nm resolution (feedback sensor limitation), and ~5 μm/s actuation speeds. A PID control loop automatically stabilizes the stage against thermal drift, as well as random thermal-induced position fluctuations (up to the bandwidth of the feedback and position sensor). Maximum actuator efficiency values of ~0.03% were measured, approximately 1000 times greater than recently reported for light-driven polymer systems.
authors.affiliation: Small Systems Laboratory, Department of Mechanical Engineering, University of Louisville, Louisville, Kentucky 40292, USA.
authors.forename: James
authors.initials: J
authors.lastname: Loomis
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Fan
authors.forename: Farhad
authors.initials: F
authors.lastname: Khosravi
authors.forename: Peng
authors.initials: P
authors.lastname: Xu
authors.forename: Micah
authors.initials: M
authors.lastname: Fletcher
authors.forename: Robert W
authors.initials: RW
authors.lastname: Cohn
authors.forename: Balaji
authors.initials: B
authors.lastname: Panchapakesan
mesh_terms: D004548:Elasticity; D020724:Elastomers / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D008027:Light; D049329:Nanostructures / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature
chemical_list: D020724:Elastomers; D011108:Polymers; D006108:Graphite