title: Spectrophotometry of Thin Films of Light-Absorbing Particles.
abstract: Thin films of dispersions of light-absorbing solid particles or emulsions containing a light-absorbing solute all have a nonuniform distribution of light-absorbing species throughout the sample volume. This results in nonuniform light absorption over the illuminated area, which causes the optical absorbance, as measured using a conventional specular UV-vis spectrophotometer, to deviate from the Beer-Lambert relationship. We have developed a theoretical model to account for the absorbance properties of such films, which are shown to depend on the size and volume fraction of the light-absorbing particles plus other sample variables. We have compared model predictions with measured spectra for samples consisting of emulsions containing a dissolved light-absorbing solute. Using no adjustable parameters, the model successfully predicts the behavior of nonuniform, light-absorbing emulsion films with varying values of droplet size, volume fraction, and other parameters.
authors.affiliation: Department of Chemistry, University of Hull , Hull HU6 7RX, U.K.
authors.forename: Bernard P
authors.initials: BP
authors.lastname: Binks
authors.affiliation: Department of Chemistry, University of Hull , Hull HU6 7RX, U.K.
authors.forename: Paul D I
authors.identifier: 0000-0003-1578-5069
authors.initials: PDI
authors.lastname: Fletcher
authors.affiliation: Department of Chemistry, University of Hull , Hull HU6 7RX, U.K.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Johnson
authors.affiliation: Department of Chemistry, University of Hull , Hull HU6 7RX, U.K.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Marinopoulos
authors.affiliation: GSK Consumer Healthcare (U.K.) Ltd., 980 Great West Road, Brentford, Middlesex TW8 9GS, U.K.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Crowther
authors.affiliation: GSK Consumer Healthcare, 184 Liberty Corner Road, Warren, New Jersey 07059, United States.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Thompson