Chemical Modification of Carbon Materials with Sulfur Functionalities
- PDF / 2,689,092 Bytes
- 11 Pages / 612 x 792 pts (letter) Page_size
- 46 Downloads / 222 Views
1039-P07-01
Chemical Modification of Carbon Materials with Sulfur Functionalities Takako Nakamura, and Tsuguyori Ohana Research Center for Advanced Carbon Materials, National Institute of Advanced Industrial Science and Technology, Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan ABSTRACT Photolysis of cyclic disulfides in the presence of carbon materials such as diamond films and single-walled carbon nanotubes led to surface modifications that introduce thioalkylthiol functional groups. This was confirmed by Raman, X-ray photoelectron spectroscopy and mass spectrometer measurements. The results on the value of S/C ratio of sulfur-modified diamond films depends on irradiation time by monitoring with XPS. Attachment of gold nanoparticles using self-assembly process was performed on the carbon materials surfaces through thioalkylthiol moieties. INTRODUCTION Carbon materials such as diamond, carbon nanotubes and related materials have attracted much attention for use in a wide range of applications because of their unique electronic, optical and mechanical properties [1-3]. Surface modifications of carbon materials have been expected to lead to improvements in the original behavior of these materials, especially for making it possible to immobilize DNA moieties steadily and to introduce novel functions to the surfaces [4-7]. Sulfur-containing materials have attracted much attention because of properties derived from the presence of sulfur atoms [8]. Especially, it is well known that organic compounds containing thio- and thiol groups play an important role in the structure of biomolecules and show good affinities with gold that result in self-assembled monolayer. To date, chemical modification of the surface of carbon materials with sulfur-containing substituents have been studied by use of H2S gas using the ball-milling method [9] and the chemical vapor deposition method [10]. These methods involve difficulties in handling that make it necessary to use special vessels and multi-step reactions. Previously we reported that a photochemical modification of carbon materials with fluorine functionalities by the use of organic radical reactions under mild conditions [11, 12]. It is known that cyclic disulfides are photolysed easily to give α,ω-alkyldithio radicals [13]. In this paper, we report on a useful method of surface modification of carbon materials with sulfur-containing substituents by using a radical process of the photolysis of cyclic disulfides. A subsequent attachment of gold to the surface of carbon materials was investigated through sulfur moieties linkage. EXPERIMENT Diamond films on Si substrate were purchased from Sumitomo Electric Industries Co.,
Ltd. as polycrystalline films grown by CVD method. Single-walled carbon nanotubes (SWNTs, 0.9-1.2 nm diameter, 10-50 µm length) were purchased from Aldrich Co. Inc. Cyclic disulfides 1 was prepared according to the literature [14]. Acetonitrile was obtained from Kanto Chemical Co., Inc. Gold colloid was synthesized according to the literature [15]. C
Data Loading...
