We present an improvement in the rate, utility, and mechanistic understanding of mono-μ-oxo-dialuminum initiators for epoxide ring-opening polymerization.

We report a partial elucidation of the relationship between polymer polarity and ionic conductivity in polymer electrolyte mixtures comprising a homologous series of nine poly(vinyl ether)s (PVEs) and lithium bis(trifluoromethylsulfonyl)imide. Recent simulation studies have suggested that low dielectric polymer hosts with glass transition temperatures far below ambient conditions are expected to have ionic conductivity limited by salt solubility and dissociation. In contrast, high dielectric hosts are expected to have the potential for high ion solubility but slow segmental dynamics due to strong polymer−polymer and polymer−ion interactions. We report results for PVEs in the low polarity regime with dielectric constants of about 1.3 to 9.0. Ionic conductivity measured for the PVE and salt mixtures ranged from about 10 −10 to 10 −3 S/cm. In agreement with the predictions from computer simulations, the ionic conductivity increased with dielectric constant and plateaued as the dielectric approached 9.0, comparable to the dielectric constant of the widely used poly(ethylene oxide).

Humidity control is relevant to many processes in buildings and manufacturing and is responsible for over 600 million tons of CO2 annually. As such, desiccants that can efficiently remove moisture from air can greatly reduce emissions. A new class of desiccant materials, thermo‐responsive desiccants, has been of increased interest in the literature. These materials are generally based on thermo‐responsive polymers and exhibit a temperature‐dependent isotherm, an attribute that is small in traditional desiccants. In this work, seven key parameters needed to create an effective thermo‐responsive polymer desiccant are identified using a combination of modeling and experimental data. It is found that more thermo‐responsiveness is not necessarily better for energy efficiency, and that an optimal, “medium” value is desired. Additionally, polymer composition and architecture play key roles in adjusting the seven key parameters. Finally, based on findings from both modeling and experimental work, guidelines on synthesizing future thermo‐responsive polymer desiccants are presented.

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