Pyris 1 dsc instrument

The curing process of the nanocomposites was investigated by differential scanning calorimetry under non-isothermal conditions at heating rates of 5, 10, 15 and 20 °C/min. Isothermal scans were performed at T = 50 °C on selected PDMS-based samples. A Pyris 1 DSC instrument (Perkin–Elmer, Waltham, MA, USA) calibrated with high-purity indium and tin materials was used. DSC samples were prepared starting from each mixture immediately after the addition of the curing agent. Samples (~20 mg) were sealed in aluminum pans with lids and measured in the temperature range from 30 °C to 150 °C under a constant flow of nitrogen (20 mL/min). An identical empty cell was taken as the reference. A baseline was measured at the same experimental conditions using an empty cell and subtracted from the sample data. The exothermic peaks were analyzed using the thermal analysis software provided with the instrument. The heat flow data were processed to obtain the extent of conversion (α) as a function of temperature using the Perkin–Elmer Kinetics Software package (Perkin–Elmer, Waltham, MA, USA).

X-ray powders diffraction (XRPD) of different nanocrystals was analyzed with a D2 Phaser diffractometer (BrukerCorp, Billerica, Massachusetts) with a Cu-Kα radiation source and a LYNXEYETM-compound silicon strip detector. The powder patterns were obtained from 0 to 50° 2θ at a scan speed of 5°/min and a step size of 0.02°. The voltage and current used were 40 kV and 100 mA, respectively. Differential scanning calorimeter (DSC) analysis of different nanocrystals was measured by a Perkin–Elmer Pyris 1 DSC instrument (Waltham, MA, USA) with an Intra-cooler 2P cooling accessory. The pre-weighed samples were sealed into standard aluminum pans and scanned from 0 to 500 ℃ at a heating rate of 10 ℃/min with a nitrogen purge of 10 mL/min, respectively.

Transmission electron microscopy (TEM) analysis was performed with a FEI Tecnai TF20 TEM instrument at an accelerating voltage of 200 kV. Samples were prepared by evaporating a drop of dilute GNR solutions in chloroform onto carbon-coated copper TEM grids (400 mesh, TED PELLA, Inc.), which were allowed to dry for 24 h prior to imaging. Freeze-fracture TEM (FF-TEM) images were obtained either on a FEI Tecnai TF30 ST TEM instrument at an accelerating voltage of 300 kV or a JEOL JEM-100S at 100 kV. The FF-TEM samples, replicas of fractured surfaces of the LC-GNR composites, were prepared following a procedure described elsewhere^{51 (link)}. UV-Vis absorption and solution circular dichroism (CD) spectropolarimetry measurements were done using an OLIS spectrophotometer (1 cm path length quartz cuvettes). ¹H NMR spectra were recorded in CDCl₃ on a Bruker DMX 400 MHz spectrometer and referenced internally to residual solvent peaks at 7.26 ppm. Polarized optical microscopy (POM) observations of the induced chiral nematic liquid crystals (N*-LCs) were recorded and photographed using an Olympus BX-53 polarizing microscope equipped with a Linkam LTS420E heating/cooling stage. Differential scanning calorimetry (DSC) was performed using a Pyris 1 DSC instrument (Perkin Elmer). Thermogravimetric analysis (TGA) was performed using a TGA Q500 (TA Instruments).