Propiolic acid

Sodium p-styrenesulfonate hydrate (TCI, > 93.0%) (NaStS); copper(I) bromide 98% (Sigma-Aldrich, Seoul, South Korea) (Cu^IBr); 4-(bromomethyl)benzoic acid 97% (Alfa Aesar, Seoul, South Korea) (BMB); 2,2′-bipyridine (bpy) 99.5% (Junsei, Tokyo, Japan); 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (TCI, > 98.0%) (DMTMM); propiolic acid (TCI, > 97.0%) (PA); 1-hexylamine 99% (Sigma-Aldrich) (HA); and ninhydrin (TCI, > 98%) were used as received, without further purification. Silica gel 60 (Merck, 0.063-0.200 mm) was used for the column chromatography while tetrahydrofuran (Duksan, extra pure grade) (THF) was used to improve the purity of the polymer through solvent-precipitation. Deuterium oxide 99.9% D (Cambridge Isotope Laboratories, Inc., Seoul, South Korea) (D₂O) was used as the NMR solvent. Polystyrene microparticles (5% w/v, 2.0–2.2 μm diameter) having surfaces functionalized with amine groups, were procured from Spherotech, IL, Illinois, USA.

The experimental setup used in this work to synthesize amorphous carbon nanospheres (Fig. 1) is shown in Figure S1. Argon was used as the carrier gas at a flow rate of 1 L/min. The carrier gas was flowed through the reactor for at least 30 min to purge the system prior to the addition of the precursor solution which was prepared by stoichiometrically mixing propiolic acid (95% from sigma-aldrich) with coressponding alkali hydroxides (99.99% from sigma-aldrich). The obtained black powders were washed and centrifuged with deionized water for at least 5 times to remove any salt formed during synthesis. The N₂ adsorption-desorption was carried out using Micromeritics ASAP 2020 physisorption analyzer to determine the density of porous carbon nanospehres studied in this work. TEM images were taken with a JEOL 2100 transmission electron microscope with an accelerating voltage of 200 kV. SEM images were taken using a Hitachi S4800 field-emission scanning electron microscope with an accelerating voltage of 10 kV. Powder X-ray diffraction patterns (PXRD) of the product were obtained with a Japan Rigaku DMax-γA rotation anode X-ray diffractometer equipped with graphite monochromatized Cu Kα radiation (λ = 1.54178 Å). Raman spectra were obtained directly from a thin film of carbon samples deposited on Si wafers on a Horiba Jobin-Yvon LabRAM Raman Spectrometer (excited with a 532 nm laser).