Miscibility

About: Miscibility is a research topic. Over the lifetime, 5521 publications have been published within this topic receiving 133547 citations. The topic is also known as: miscible.

Factors Governing Intercalation of Fullerenes and Other Small Molecules Between the Side Chains of Semiconducting Polymers Used in Solar Cells

Abstract: While recent reports have established significant miscibility in polymer:fullerene blends used in organic solar cells, little is actually known about why polymers and fullerenes mix and how their mixing can be controlled. Here, X-ray diffraction (XRD), differential scanning calorimetry (DSC), and molecular simulations are used to study mixing in a variety of polymer:molecule blends by systematically varying the polymer and small-molecule properties. It is found that a variety of polymer:fullerene blends mix by forming bimolecular crystals provided there is sufficient space between the polymer side chains to accommodate a fullerene. Polymer:tetrafluoro-tetracyanoquinodimethane (F4-TCNQ) bimolecular crystals were also observed, although bimolecular crystals did not form in the other studied polymer:non-fullerene blends, including those with both conjugated and non-conjugated small molecules. DSC and molecular simulations demonstrate that strong polymer–fullerene interactions can exist, and the calculations point to van der Waals interactions as a significant driving force for molecular mixing.

Phase behavior of polymers containing ether groups in carbon dioxide

Abstract: Polyethers of different composition and chain length were investigated with regard to their solubility in CO2. The nature of the monomeric unit, the degree of polymerization, the endgroup effect, the composition and the temperature significantly influence the solubility and thus the CO2 pressures required for miscibility. In general, it was found that polymers of propylene oxide are more ‘CO2-philic’ than analogs of either ethylene oxide or tetrahydrofuran. The phase behavior of block copolymers of the ethers is influenced by both composition and topology (blocky versus random, block arrangement). It appears that the ether oxygens in polyethers enhance the solubility of such polymers (relative to simple hydrocarbons) through specific interactions with CO2, but only if the ether oxygen is in a readily accessible position.

Polyester/polycarbonate blends. I. Poly(butylene terephthalate)

Abstract: Melt blends of bisphenol A polycarbonate with poly(butylene terephthalate) were studied by DTA and dynamic mechanical behavior to determine their state of miscibility. Both techniques showed multiple glass transitions indicative of incomplete miscibility in the amorphous phase. However, these transitions in some cases did not correspond to those in the pure components and varied with overall blend composition in some instances. This indicates that there are amorphous phases containing both components, i.e., partial miscibility. This view was supported by the crystallization behavior of the polyester. Two crystallization exotherms were observed for quenched samples, which is interpreted as polyester crystallization from two separate phases, one richer in this component than the other. Other interpretations of these results are discussed.