Unity 300 mhz spectrometer

¹H NMR spectra were obtained using a Varian Unity 300 MHz spectrometer. Either chloroform-d₁ or methanol-d₄ was used as a solvent, depending on polymer solubility. Fourier transform infrared spectroscopy (FTIR) spectral studies were performed using a Nicolet/Nexus 670 FTIR spectrometer in a range between 4,000 cm⁻¹ and 500 cm⁻¹ with a resolution of 2 cm⁻¹. All powder samples were compressed into KBr pellets prior to FTIR measurements. The Mws and Mw distribution of the polymers were estimated using a gel permeation chromatography (GPC) system consisting of a styroldivinylbenzole-copolymer linear column (Polymer Standard Service, Mainz, Germany) with dichloromethane as an eluent (1 mL/min); polystyrene was used as a standard for calibration. Samples for scanning electron microscopy (SEM, Quanta 400F) analysis were prepared by drying a dispersion of the micelle solution on a clean glass slide, which was first washed with deionized water and then with acetone for 24 hours in a desiccator. A thin layer of gold was sputter coated on the samples for charge dissipation during SEM imaging.

¹H NMR spectra were recorded on a Varian Unity 300 MHz spectrometer by using dimethyl sulfoxide-d₆ (DMSO-d₆) or D₂O as the solvent. The molecular weight and polydispersity index (PDI) of PEG-PLL were evaluated by gel permeation chromatographic (GPC) system consisting of Waters 2690D separations module and Waters 2410 refractive index detector. Tetrahydrofuran (THF) was used as the eluent at a flow rate of 0.3 mL/min. The particle size and zeta potential were measured using Malvern Zetasizer Nano-ZS ZEN3600. Nitrogen adsorption−desorption isotherms were measured on a micromeritics instrument (ASAP2020). Thermal gravitational analysis (TGA) was performed with a Thermo Gravimetric Analyzer (TGS--II, Perkin-Elmer). Fluorescence analysis was performed on a RF-530/PC spectrofluorophotometer (Shimadzu). The morphologies of nanoparticles were observed on scanning electron microscopy (SEM, FEI-QUANTA 200) and transmission electron microscopy (TEM, JEM-2100).