In this work, the suitability of imidazolium-based ionic liquid solvents is investigated for the dissolution and regeneration of silkworm (Bombyx mori) silk. Within an ionic liquid the anion plays a larger role in dictating the ultimate solubility of the silk. The dissolution of the silk in the ionic liquid is confirmed using wide-angle X-ray scattering. The dissolved silk is also processed into 100 mum-thick, two-dimensional films, and the structure of these films is examined. The rinse solvent, acetonitrile or methanol, has a profound impact on both the topography of the films and the secondary structure of the silk protein. The image depicts a silkworm cocoon dissolved in 1-butyl-3-methylimidazolium chloride and then regenerated as a film with birefringence.

where Cy ) c-C 6 H 11 ) and two POSS-siloxane copolymers [Cy 8 Si 8 O 11 -(OSiMe 2 ) n O-] (n ) 1, oligomer average 5.4) has been studied in argon, nitrogen, and under vacuum from 30 to 1000 °C. Product gases were analyzed by TGA-FTIR and mass spectroscopy. Analysis of the chars was conducted using cross-polarized (CP) and magic angle spinning (MAS) NMR spectroscopy, X-ray diffraction, density measurements, and gas adsorption analysis. All of the POSS macromers showed a propensity toward sublimation, while the POSS-siloxane copolymers underwent a complex depolymerization-decomposition process. For the copolymer [Cy 8 Si 8 O 11 -(OSiMe 2 ) 5.4 O-] this process included the evolution of cyclic dimethylsiloxanes at 400 °C, cyclohexyl hydrocarbons from 450 to 550 °C, and H 2 liberation from 700 to 1000 °C. Loss of the silsesquioxane "cage" structure occurred upon heating from 450-650 °C and after the evolution of most of the pyrolysis gases. Changes in both char porosity and density accompanied the structural rearrangements. The activation energies for pyrolysis under argon or nitrogen was 56 ( 9 kcal/mol and for oxidation in air was 20 ( 4 kcal/mol.

Regenerated silk fibroin from Bombyx mori silkworms was extruded into fibers from a 1-ethyl-3-methylimidazolium chloride ionic liquid solvent system; the drawn fibers rinsed in methanol exhibit alignment of the b-sheet crystallites along the fiber axis.

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