Development of phase morphologies of poly(methyl methacrylate)-polystyrene-toluene mixtures in electric fields

Abstract

The evolution of the phase morphology of polystyrene (PSI-poly(methy1 methacrylate) (PMMA) blends during solvent casting from toluene solutions in an electric field was studied. Depending on the sizes of the phases and the electric field strength used, ellipsoidal or columnar structures could be obtained. If the field was removed while a considerable amount of solvent was present, columnar structures broke up into spherical phases via the Rayleigh instability. Partial phase diagrams were constructed for the PMMA-PS-toluene system by experimental determination of tie lines and by theoretical simulation of spinodal curves. Dielectric constants, viscosities, and interfacial tensions (using the pendant drop technique) were measured for some of the coexisting phases. Interfacial tensions calculated using the shapes of deformed drops in electric fields were very low (10-5-10-4 dyn/cm), 2-3 orders of magnitude smaller than those measured by the pendant drop method. Possible reasons for this difference are discussed.

Electrorotation of Deformable Fluid Droplets

“…It is well known that the interfacial tension between coexisting phases decreases as the tie lines move closer to the critical point because the interfacial tension must vanish at the critical point. Furthermore, we have noted similar low interfacial tensions between coexisting phases in polymer/polymer/solvent systems in previous work from this laboratory (10,11).…”

A Computational Study of the Polymerization‐Induced Phase Separation Phenomenon in Polymer Solutions under a Temperature Gradient

“…Examples of polymeric materials with anisotropic morphologies include anisotropic porous polymer membranes and switchable holographic PDLC films. [15,16] The structural anisotropy can be introduced by imposing an external fluctuation, such as an electric field, [17,18] a shear flow, [19] a concentration gradient, [15] a temperature gradient [20][21][22] or controlled chemical reaction [23][24][25][26] to the phase-separating polymeric systems. The PIPS method will be studied in this paper, for fabricating anisotropic polymeric materials by means of applying an external temperature gradient to the polymer solution.…”

A Computational Study into Thermally Induced Phase Separation in Polymer Solutions under a Temperature Gradient

“…Other potential applications include large-size projectors for displays and switchable digital zoom lenses for cameras. [9] Anisotropic morphology in polymeric materials can be created by imposing an external force, such as an electric field, [10,11] a shear flow, [12] a concentration [8] or temperature gradient [13,14] to a phase-separating system, in which the phase separation is either induced by TIPS or PIPS. An understanding of the influence of these external fluctuations on the phase-separating system provides important information on the fabrication of these modified polymeric materials.…”