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[Display omitted] • Kinetic control of pore formation in polyimides were analyzed. • The pore size can be engineered by tailoring the DBP and NH 2 -POSS concentrations. • The DBP is easily removed with common organic solvents and leaves pores in the film. • The NH 2 -POSS acts as an additional nucleating agent during the PI chain crystallization. • The resultant PPI/NH 2 -POSS x provides desirable dielectric properties in a broad frequency and temperature ranges. Fabricating porous polymer films with precise morphological control via a conventional phase separation method is challenging. Herein, porous polyimide (PPI) film formation kinetics was thoroughly investigated to understand the underlying phenomena during the thermally induced phase separation. The porous films were prepared using a poly(amic acid) (PAA) solution with a small-molecular phase dispersion agent (i.e., porogen), dibutyl phthalate (DBP), which is miscible with the PAA chains. Using amine-functionalized polyhedral oligomeric silsesquioxane (NH 2 -POSS) as an additional nucleating agent, sponge-like NH 2 -POSS end-capped PPI (PPI/NH 2 -POSS x) films were fabricated with tunable pore size (16.3–76.9 μm) and porosity (42.6–69.4 %). This ensured control over the porous structure of the PPI/NH 2 -POSS x film, providing desirable low dielectric properties (a minimum of 2 at 1 MHz) in broad frequency and temperature range as well as high thermal stability (T g = 363–385 °C, T 5% = 519–559 °C), and good mechanical strength (17–23 MPa). It was found that the porous structure and physical properties of the PPI/NH 2 -POSS x films can be readily engineered by tailoring the initial content of a removable porogen and cage silsesquioxane. This work will provide a new perspective on fabricating temperature-resistant low-dielectric porous polymer films with tunable pore sizes via thermal-driven spontaneous phase separation with efficient processability. [ABSTRACT FROM AUTHOR]

A series of soy protein isolate (SPI)-based film-forming solutions were prepared by a co-drying process or by direct addition of alginate (ALG), with different degrees of phase separation and morphologies. For a non-phase separation system, a single Tg of the data was well fit by the calculation results of the Couchman–Karasz quotation; moreover, the initial state of SPI/ALG (20:1) and SPI/ALG (10:1) after homogenization and the state of SPI/ALG (20:1) after deposition for 30 min exhibited good uniformity; thus, a single Tg value was also measured in these cases (96.28 °C, 85.37 °C and 112.03 °C respectively). Two Tg values of 74.11 °C and 108.24 °C for SPI/ALG (20:1), 72.86 °C and 110.11 °C for SPI/ALG (10:1) were determined in the 100% of phase separation systems. The mixed interface, SPI-rich phase, and ALG-rich phase of SPI/ALG (10:1) co-blending system after deposition for 30 min were formed, resulting in three different Tg values of 74.32 °C, 90.15 °C and 125.17 °C. The SPI/ALG-CO (20:1) and SPI/ALG-CO (10:1) systems with co-drying process could significantly improve the interface properties and the surface activity of each component. The understanding of Tg led to new insights of defining the limit between the rubbery and glassy states in the film-forming co-blending systems. [ABSTRACT FROM AUTHOR]

We review a few simulation methods and results related to the structure and non-equilibrium dynamics in the coexistence region of immiscible symmetric binary fluids, in bulk as well as under confinement, with special emphasis on the latter. Monte Carlo methods to estimate interfacial tensions for flat and curved interfaces have been discussed. The latter, combined with a thermodynamic integration technique, provides contact angles for coexisting fluids attached to the wall. For such three-phase coexistence, results for the line tension are also presented. For the kinetics of phase separation, various mechanisms and corresponding theoretical expectations have been discussed. A comparative picture between the domain growth in bulk and confinement (including thin-film and semi-infinite geometry) has been presented from molecular dynamics simulations. Applications of finite-size scaling technique have been discussed in both equilibrium and non-equilibrium contexts. [ABSTRACT FROM PUBLISHER]

The thermally induced phase separation behavior of hydrogen bonded polymer blends, poly( n-hexyl methacrylate) (PHMA) blended with poly(styrene- co-vinyl phenol) (STVPh) random copolymers having various vinyl phenol contents, was studied by temperature modulated differential scanning calorimetry (TMDSC).The enthalpy of phase separation was determined to be about 0.5 cal g−1 for one of the blends. A phase diagram was constructed from the TMDSC data for one of the blends. The kinetics of phase separation was studied by determining the phase compositions from the glass transition temperatures of quenched samples after phase separation. Subsequently, the phase separated samples were annealed at temperatures below the phase boundary to observe the return to the homogeneous state. [ABSTRACT FROM AUTHOR]

Elastic interactions arising from a difference of lattice spacing between two coherent phases can have a strong influence on the phase separation (coarsening) behavior of alloys. If the elastic moduli are different in the two phases, the elastic interactions may accelerate, slow down or even stop the phase separation process. If the material is elastically anisotropic, the precipitates can be shaped like plates or needles instead of spheres and can arrange themselves into highly correlated patterns. Tensions or compressions applied externally to the specimen may have a strong effect on the shapes and arrangement of the precipitates. In this paper, we review the main theoretical approaches that have been used to model these effects and we relate them to experimental observations. The theoretical approaches considered are (i) “macroscopic” models treating the two phases as elastic media separated by a sharp interface, (ii) “mesoscopic” models in which the concentration varies continuously across the interface, and (iii) “microscopic” models which use the positions of individual atoms. [ABSTRACT FROM AUTHOR]