Acknowledgements The authors would like to thank the Department
of Chemistry of Khon Kaen University for providing FT-IR and
VSM facilities, the Faculty of Science Electron Microscopy Unit for
providing SEM facilities, and the National Metal and Materials Technology
Center (MTEC) of NSTDA for providing TG/DTA and TEM
facilities. S. Daengsakul would like to thank the TGIST scholarship
for the support of her Ph.D. study. This work is financially supported
by The National Research Council of Thailand (NRCT) under the research
contract no. PorKor/2550-287.