Reduction of nGO-PEG. (A) UV-vis spectra of nGO, nGO-COOH, and nGO-PEG suspension with approximately 15 μg/mL of GO (1 cm optical path). Inset: photographs of nGO, nGO-COOH, and nGO-PEG suspension at the same GO concentration (1) before and (2) after storage for a week at 4°C. (B) UV-vis absorption spectra of the nGO-PEG solution bathed at indicated temperature for 24 h. Inset: photographs of nGO-PEG at the indicated temperature for 24 h. (C) UV-vis absorption spectra of the nGO-PEG solution bathed at 90°C for various time. Inset: photographs of nGO-PEG bathed at 90°C for various time (0, 6, 12, 18, 24 h). (D) UV-vis spectra of (a) nrGO and (b) nrGO-COOH suspension bathed at 90°C for 24 h.
Chen et al. Nanoscale Research Letters 2014 9:86 doi:10.1186/1556-276X-9-86