Alpha p ft ir spectrophotometer

The chemical structures of microPCM and each of its components (i.e., PLA and PA) were analyzed using Fourier transform infrared (FTIR) spectroscopy (Bruker Alpha-P FT-IR Spectrophotometer). The spectra were collected by averaging signals from 32 scans at a resolution of 4 cm⁻¹ in the range of 400–4000 cm⁻¹.
Scanning electron microscopy (SEM) (FEI Company, Quanta 3D FEG) was used to observe the morphologies (i.e., surface features and sphericity) and sizes of microPCM. The fabricated microPCM were sputter coated with gold (Denton Vacuum, Desk V Sputter Coater) before the observation. The particle sizes were obtained by analyzing the SEM micrographs using ImageJ (NIH Image). The interior morphology of microPCM was exposed by microtoming microcapsules using a diamond knife.
The enthalpy of fusion and the melting point of microPCM were determined by a differential scanning calorimetry (DSC) (TA Instrument, DSC Q20). These measurements were performed in the temperature range from 40 to 90 °C at a heating rate of 10 °C min⁻¹. In order to determine the thermal stability of the microPCM, the enthalpy of fusion was analyzed after samples [i.e., the base case (PCM0.6)] were subjected to 50 thermal cycles at the same temperature range and heating rate.

The size and morphology of AgNPs and CA-AgNPs/MWCNTs was determined by using a model JEOL2100 TEM instrument (München, Germany) fitted with a LaB 6 electron gun at 5 kV, and the images were captured using an Ultrascan digital camera (Gatan, München, Germany). Samples were prepared after sonication for 1 h by placing a drop of fresh suspension on the TEM copper grids, followed by solvent drying and evaporation. The surface morphology of the AgNPs was observed using a Quanta FEG 250 Environmental Scanning electron microscope (ESEM, Hillsboro, OR, USA) under an acceleration voltage of 30 kV. Powdered samples were placed on the sample stumps and a thin gold layer was deposited on the samples to improve the electrical conductivity for better imaging. Simultaneously, the energy dispersive spectrum (EDS) was also recorded. FTIR spectroscopy measurements were carried out to identify the functional groups which are bound distinctively on the AgNPs surface and involved in the synthesis of AgNPs. Samples for the FTIR analysis were recorded using an alpha-P FT-IR spectrophotometer (Bruker, Bryanston, Sandton, Gauteng, South Africa.) in the wavenumber range 400–4000 cm⁻¹. Thermal analysis was performed using a TG/DSC SDT600 thermogravimetric analyzer (TA instruments, New Castle, DE, USA) under nitrogen flow.