Freeze-drying-induced changes in the properties of graphene oxides.
We have characterized and evaluated changes in graphene oxide (GO) induced by means of freeze-drying. In order to evaluate these changes, we investigated the effects of freeze-drying and chemical reduction processes on the structure, morphology, chemical composition, and Raman properties of GO and reduced GO. The freeze-dried GO had a pore structure, maintaining a pored morphology even after thermal annealing. The freeze-dried samples were composed of a single folded nanosheet or a few nanosheets stacked and folded. The oxygen-containing functional groups were removed not only during the freeze-drying but also during the reduction processes, with an accompanying decrease in the average size of the sp(2) carbon domain (i.e. an increase in the ID/IG value).
Department of Liberal Arts and Sciences, and Nanomaterial Research Center, H&H Co. LTD, Chungju National University, 50 Daehak-ro, Chungju-si, Chungbuk, 330-702, Republic of Korea.
Heon
H
Ham
Tran Van
TV
Khai
No-Hyung
NH
Park
Dae Sup
DS
So
Joon-Woo
JW
Lee
Han Gil
HG
Na
Yong Jung
YJ
Kwon
Hong Yeon
HY
Cho
Hyoun Woo
HW
Kim