Spinodal nanostructures in polymer blends: On the validity of the Cahn-Hilliard length scale prediction

Small Angle Neutron Scattering Study of the Thermodynamics of Highly Interacting PαMSAN/dPMMA Blends

“…PαMSAN/ dPMMA form a lower critical solution temperature (LCST) mixture, whose glass transition temperature (T g ≈ 120 • C) is near the critical temperature (≈ 140 • C), thus enabling precise time-resolved SANS experiments. This system has been previously reported by Higgins et al 16 and identified as a highly interacting blend, 15 in terms of the magnitude of G for a modest, accessible quench depth ∆T within the spinodal line. In simple terms, refined below, this blend exhibits a large β (or slope) in the descriptive relation G = α + β/T .…”

“…[12][13][14] ) with a combination of light, neutron, X-ray scattering as well as various microscopies. A few studies have examined the validity of the C-H prediction of the initial lengthscale of polymer blend demixing, which we have have recently reviewed and found to be remarkably accurate, 15 despite neglecting hydrodynamic interactions, non-linear terms to the diffusion equation and limitations of the mean field assumption for blends (involved in estimating G and particularly k). Extrapolation of G (T ) with temperature from the one-phase region, which is positive, to the two-phase region, across the spinodal line, where it becomes negative, appears thus an effective approach to selecting G and, in turn q * to predictively design bicontinuous structures.…”

“…Parameter k thus relates to ∼ b 2 i /v i as well as composition, typically varying from 0.05-0.2Å 2 mol/cm 3 across typical systems. 15 We therefore compile previously reported data for G /k as a function of ∆T for a range of even steeper G /k slopes, 15,39,40 albeit within a narrow miscibility window, highly sensitive to the regularity and extent of chlorination of PE. 39 From a practical standpoint, the proximity of T g and T s in PαMSAN/dPMMA blends make T-jump experiments feasible with the expectation of relatively slow structural coarsening.…”

Two-dimensional Cahn–Hilliard simulations for coarsening kinetics of spinodal decomposition in binary mixtures

“…From the linear analysis of the Cahn-Hilliard equation the time needed for the SD to take place t 0 , and the initial characteristic size L 0 of the separated phases can be calculated as 23,78…”

Structural hierarchy in blends of amphiphilic block copolymers self-assembled at the air-water interface

“…30 A related process on much longer length scales is the phase separation of non-connected and dissimilar polymer chains via spinodal decomposition within polymer blends, which forms microscale and macroscale domain patterns. 31 In order to direct pattern formation in both of these phase separation processes, many groups have explored the use of solid surfaces to introduce physical and chemical confinement. [32][33][34][35][36][37] However, an interesting and completely novel idea is to investigate polymer-polymer phase separation confined to a liquid surface, by separately anchoring the dissimilar phase-separating 4 blocks to the air-water interface via attached hydrophilic blocks.…”