title: Thermosensitive hard spheres.
abstract: We demonstrate an extension of a UV-Vis spectroscopy method to determine the phase boundaries for thermosensitive colloids as an alternative to the time-consuming sedimentation method. The Bragg attenuation peak from colloidal crystallites was monitored during the quasi-equilibrium colloidal crystal melting. The melting and freezing boundaries of the coexistence region were determined via a blue shift of Bragg's peak and the disappearance of peak area. We confirm this method using poly(N-isopropylacrylamide) (PNIPAM) particles at different charge densities and temperatures far below the lower critical solution temperature. At low pH, the particles behave as thermosensitive hard spheres.
authors.affiliation: Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Clements
authors.forename: Srinivasa Rao
authors.initials: SR
authors.lastname: Pullela
authors.forename: Andres F
authors.initials: AF
authors.lastname: Mejia
authors.forename: Jingyi
authors.initials: J
authors.lastname: Shen
authors.forename: Tieying
authors.initials: T
authors.lastname: Gong
authors.forename: Zhengdong
authors.initials: Z
authors.lastname: Cheng