Nylon supported membrane

RGO and RGO_1700 flakes were prepared accordingly with the previously reported method [32 (link)], consisting of highly reduced nanoflakes having lateral size ranging between 0.5 and 2 µm and thickness between 4 and 15 nm (full characterization previously reported in [32 (link)]). RGO and RGO_1700 were suspended in DMF at concentrations of 0.15 mg·mL⁻¹ and the solutions were sonicated in pulsed mode (15 s on and 15 s off) for 15 min with power set at 30% of the full output power (750 W), to avoid significant temperature increase during the treatment, by using an ultrasonication probe (Sonics Vibracell VCX-750, Sonics & Materials Inc., Newtown, CT, USA) with a 13 mm diameter Ti-alloy tip. The RGO and RGO_1700 suspensions were subjected to vacuum filtration using a Nylon Supported membrane (0.45 μm nominal pore size, diameter 47 mm, Whatman, Buckinghamshire, UK). After filtration, the as-obtained papers were peeled off from the membranes and dried at 65 °C under vacuum for 2 h to completely remove the solvent. Finally, RGO and RGO_1700 nanopapers were mechanically pressed in a laboratory hydraulic press (Specac Atlas 15T, Orpington, UK) under a uniaxial compressive load of 5 kN for 10 min at 25 °C.

One hundred milligram GnP were added to a 100 mL solution of Pyr-L in DMF (0.5 mg·mL⁻¹) and sonicated in pulsed mode (30 s ON and 30 s OFF) for 15 min with power set at 30% of the full output power (750 W) by using an ultrasonication probe (Sonics Vibracell VCX-750, Sonics & Materials Inc.) with a 13 mm diameter Ti-alloy tip. After that, the suspension was left to stand for 24 h to ensure the adsorption of the stereoisomer on the basal plane of GnP. Then, the suspension was filtered through a Nylon Supported membrane (0.45 μm nominal pore size, diameter 47 mm, Whatman) and the filtrate analyzed by UV-Vis. The filtered cake was re-dispersed in DMF (50 mL), sonicated in an ultrasonication bath for 10 min, filtered and the filtrate analyzed by UV-Vis. The dispersion-filtration cycle was repeated a second time to ensure the completely disappearance of the Pyr-L on the filtrate. Finally, the functionalized GnP were washed with methanol (50 mL) and diethyl ether (50 mL) and dried at 60°C for 24 h.