title: An acoustic dielectric and mechanical spectrometer.
abstract: In this report, the dielectric constant of glycerol solutions (0-70% (w/w)) and the mechanical transitions of poly(2-hydroxylethyl methacrylate-co-methacrylic acid) films (600-800 nm, 1.5-10 mol% cross-linker) have been investigated by the magnetic acoustic resonance sensor (MARS), which is an electrode-free acoustic sensor and operates over a continuous frequency spectrum (6-200 MHz). When a glycerol solution was loaded, the response of the MARS decayed exponentially as the operating frequency was increased. The decay rate against frequency as a function of the glycerol concentration reflects the change of the dielectric property of the glycerol solutions. In addition, mechanical relaxation of the poly(2-hydroxylethyl methacrylate-co-methacrylic acid) film has been observed on the MARS and the corresponding viscoelastic transition frequency has been estimated. The viscoelastic transition frequency increased as the polymer was more highly cross-linked. The MARS system behaved as a dielectric and mechanical spectrometer, monitoring the electrical and mechanical properties of viscoelastic materials or on the solid-liquid interfaces simultaneously, which has prospective application in studies of biomaterials, molecular interactions and drug deliveries.
authors.affiliation: Institute of Biotechnology, Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QT, UK.
authors.forename: Ruifen
authors.initials: R
authors.lastname: Hu
authors.forename: Adrian C
authors.initials: AC
authors.lastname: Stevenson
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Lowe
mesh_terms: D000162:Acoustics; D004548:Elasticity; D017097:Electric Impedance; D005990:Glycerol / Q000737:chemistry; D055595:Mechanical Phenomena; D011108:Polymers / Q000737:chemistry; D013057:Spectrum Analysis; D013997:Time Factors; D014783:Viscosity
chemical_list: D011108:Polymers; D005990:Glycerol