Fig. 1

a Synthetic scheme of PEG-PA, PEG-PAO, and PEG-PAS. b 1H-NMR spectra of PEG-PA, PEG-PAO, and PEG-PAS. CF3COOD was used as an NMR solvent. m and n determined by 1H-NMR, are 45 and 16, respectively
a Synthetic scheme of PEG-PA, PEG-PAO, and PEG-PAS. b 1H-NMR spectra of PEG-PA, PEG-PAO, and PEG-PAS. CF3COOD was used as an NMR solvent. m and n determined by 1H-NMR, are 45 and 16, respectively