Đang chuẩn bị liên kết để tải về tài liệu:
Báo cáo vật lý: "FORMATION AND MORPHOLOGY OF COLLOIDAL CHITOSAN-STABILIZED COPPER SULFIDES"

Tuyển tập các báo cáo nghiên cứu khoa học trên tạp chí khoa học vật lý quốc tế đề tài: FORMATION AND MORPHOLOGY OF COLLOIDAL CHITOSAN-STABILIZED COPPER SULFIDES | Journal of Physical Science Vol. 18 1 87-101 2007 87 FORMATION AND MORPHOLOGY OF COLLOIDAL CHITOSAN-STABILIZED COPPER SULFIDES H.T. Boey W.L. Tan N.H.H. Abu Bakar M. Abu Bakar and J. Ismail Nanoscience Research Laboratory School of Chemical Sciences Universiti Sains Malaysia 11800 USM Pulau Pinang Malaysia Corresponding author bmohamad@usm.my Abstract The reactions of copper II acetate with thiourea with or without chitosan are described. The products obtained are CuS and Cu2S in an approximate composition of 1 1. UV-vis Raman and FTIR spectroscopy as well as EDX analysis confirmed these copper sulfides. The effects of chitosan on the morphology of the copper sulfides were studied via TEM and SEM microscopy. In the absence of chitosan fractal morphology was observed D value 1.74 . In the presence of chitosan colloidal copper sulfides were obtained. For the colloid an increase in chitosan concentration resulted in smaller copper sulfides particle size i.e. decreasing from 118.8 to 76.6 nm. A plausible mechanism of the copper sulfides formation via the involvement of ethanoate ions is also described. Keywords chitosan copper sulfide thiourea morphology colloid 1. INTRODUCTION The study of transition metal chalcogenides as nanomaterials has come under intense scrutiny by material scientists recently. Of the transition metal chalcogenides sulfides and selenides have drawn considerable attention due to their interesting and excellent chemical and physical properties.1 2 Transition metal sulfides have numerous applications in various fields. Some transition metal sulfides are highly refractory with melting points exceeding those of oxides and are stable during thin film formation by vacuum deposition. Most of these sulfides are crystalline and exhibit high lubricities. These features make these sulfides a far better photo-luminescent material as compared to oxides.3 Many sulfides exhibit semi-metallic behaviour with respect to the ability to form multiple oxidation .