**7. Characterizations of nanoparticles**

Variety of techniques used to find out the chemical formula and structural confirmations of polymers after synthesis, for example, nuclear magnetic resonance (NMR) followed by the 1 H and 13C for functional groups, chemical formula, and structure of the synthesized compound. Spectrophotometer fourier transform infrared (FTIR) for functional groups identification and it has been acquired through the absorption spectra followed by the analysis of peak positions, highresolution mass spectrometer (HRMS), and low-resolution mass spectrometer to measure the molecular weight of samples, and this technique give very much

accurate mass of the synthesized compounds, matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) to measure the molecular mass of heavier compounds such as polymer macromolecules, mass of genetic materials such as deoxyribonucleic acid (DNA), ribonucleic acid (RNA) and other biomolecules, carbon, hydrogen, nitrogen, sulfur (CHNS) analyzer. Once the synthesized molecules are confirmed, then it needs microscopic characterizations for the morphology of polymeric nanoparticles. Morphology of polymer nanoparticles has been characterized by using scanning electron microscope (SEM), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) for morphology of nanoparticles, X-ray diffraction (XRD) to know the solid state and nature of materials such as amorphous, crystalline and partially crystalline nature of synthesized nanoparticles, energy dispersive spectroscopy (EDAX) for the presence of elements and elemental composition in the final compound, Brunauer–Emmett–Teller (BET) to measure the BET surface area, porosity, pore width, pore thickness, specific surface area, Langmuir surface area through the nitrogen (N2) gas adsorption and desorption hysteresis curve analysis, Atomic force microscope (AFM) for surface properties like smooth/hard/rough surface of the polymer and non-polymer nanoparticles followed by the pore profile such as pore depth and width in case of porous capsules or particles, apart from this characterization Optical profilometer can also use to evaluate the surface properties of nanoparticles and thin films. To examine the thermal properties and degradation behavior of nanoparticles, the following characterization techniques are used such as differential scanning calorimetry (DSC) for heat flow measurements such as endo- and exothermic nature of particles. Endothermic has been defined as the system which absorbs heat from surrounding and exothermic the system which releases heat to surroundings, thermogravimetric analysis (TGA) for weight loss and degradation temperature of various nanoparticles, Raman to measure the band gap, dynamic light scattering (DLS) for particle size analysis, zeta potential to measure the charge of the polymeric and non-polymeric nanoparticles.
