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PEP-PEO block copolymer micelles offer the possibility to investigate phase behaviour and interactions of star polymers (ultra-soft colloids). A star-like architecture is achieved by an extremely asymmetric block ratio (1:20). Micellar functionality f can be smoothly varied by changing solvent composition (interfacial tension). Structure factors obtained by SANS can be quantitatively described in terms of an effective potential developed for star polymers. The experimental phase diagram reproduces to a high level of accuracy the predicted liquid/solid transition. Whereas for intermediate f a bcc phase is observed, for high f the formation of a fcc phase is preempted by glass formation., Comment: 5 pages, 4 figures, PRL in press

Ternary water-in-oil microemulsions formed from an ammonium carboxylate PFPE surfactant of molecular weight 710 and a PFPE oil of molecular weight 900, leading to microemulsions that show a dynamic percolation phenomenon, were investigated by SANS to characterize the microstructure. Hard sphere and adhesive hard sphere potentials were used to model the droplet–droplet interactions assuming polydispersed droplets with a Schultz distribution of sizes.

Silk artifacts are a valuable artistic and historical heritage, but are prone to degradation that makes the fibers fragile, hindering the preservation of precious collections. Dispersions of self-regenerated silk fibroin (SRSF) can be used to cast films on aged fibers and recover their mechanical properties, but there appears to be a limit to the fibroin concentration in the dispersions, as too concentrated systems produce highly crystalline but mechanically brittle films. Alternatively, we propose here hybrid dispersions of SRSF and cellulose nanocrystals (CNC) with the aim to grant the aged fibers improved strength, taking advantage of the SRSF structuration induced by CNC, and of the intrinsic mechanical properties of the cellulose crystals. We demonstrate that CNC speeds up the assembly of fibroin in the hybrid dispersions, leading to the formation of more compact colloidal structures at the nanoscale than the sole SRSF. When the hybrid dispersions film, the presence of CNC favors the formation of crystalline structures (most notably α-helices) even at low fibroin concentration, and the films confer optimal axial strength to aged silk fibers, surpassing the performance of single-component (SRSF or CNC) dispersions at the same concentration of consolidant, and of pure crystalline SRSF. Overall, the hybrid formulations candidate as new sustainable tools for the preservation of historical textiles, employing renewable materials (cellulose and silk scraps) to restore artifacts.