Ricerc@Sapienza

We report on the extrinsic chirality behavior of GaAs-based NWs asymmetrically
hybridized with Au. The samples are fabricated by a recently developed,
lithography-free self-organized GaAs growth, with the addition of AlGaAs shell and
GaAs supershell. The angled Au flux is then used to cover three-out-of-six sidewalls
with a thin layer of Au. Oblique incidence and proper sample orientation can lead
to circular dichroism. We characterize this chiral behavior at 532 nm and 980 nm

The effects that an increase of environmental pH has on the triple helix of scleroglucan (Sclg)
and on the Sclg/borax hydrogel are reported. Rheological experiments show that the hydrogel is less
sensitive to pH increase than Sclg alone, while at pH = 14 a dramatic viscosity decrease takes place for
both systems. This effect is evidenced also by the reduced water uptake and anisotropic elongation
detected, at pH = 14, by the swelling behaviour of tablets prepared with the Sclg/borax system.