Control of the interparticle spacing in superparamagnetic iron oxide nanoparticle clusters by surface ligand engineering

Wang Dan¹, Lin Bingbing¹, Shen Taipeng¹, Wu Jun¹, Hao Fuhua², Xia Chunchao³, Gong Qiyong³, Tang Huiru², Song Bin³, Ai Hua^{1, 3, †,}

(a) OA-SPIO nanocrystals were transferred to DMF solution (lower) from hexane (upper) after ligand exchange; (b) TEM images of SPIO nanocrystals before and after ligand exchange; (c) comparison of the ¹H HRMAS NMR spectra of surfactant-coated SPIO nanocrystals dispersed in CDCl₃ at a 5 kHz MAS rate.