Grantee Research Project Results
2004 Progress Report: μ-Integrated Sensing System (μ-ISS) by Controlled Assembly of Carbon Nanotubes on MEMS Structures
EPA Grant Number: R830901Title: μ-Integrated Sensing System (μ-ISS) by Controlled Assembly of Carbon Nanotubes on MEMS Structures
Investigators: Mitra, Somenath , Iqbal, Z.
Current Investigators: Mitra, Somenath
Institution: New Jersey Institute of Technology
EPA Project Officer: Hahn, Intaek
Project Period: May 15, 2003 through May 14, 2006
Project Period Covered by this Report: May 15, 2003 through May 14, 2004
Project Amount: $346,000
RFA: Environmental Futures Research in Nanoscale Science Engineering and Technology (2002) RFA Text | Recipients Lists
Research Category: Nanotechnology , Safer Chemicals
Objective:
The development of sensitive sensors for real-time detection of airborne organics at trace levels is necessary for regulatory purposes and also for public health monitoring. The objective of this research project is to develop microscale sensing systems and instrumentation for environmental monitoring. The proposed devices will exploit some of the remarkable nanoscale properties of carbon nanotubes (CNTs) to provide online concentration data via quantum scale adsorption processes, attaining the low detection limits necessary for environmental sensing.
Progress Summary:
The major focus during this reporting period has been the development of technology for the self-assembly of carbon nanotubes (CNTs) on analytical devices and structures. This focus was to develop a microtrap for the adsorption/desorption of trace organics. The microtrap functioned as a nanoconcentrator and an injector for sensors or analytical instruments such as gas chromatography. The CNTs were deposited as a thin film by catalytic chemical vapor deposition (CVD) using either CO or C2H4 as the precursor. Typical CNT growth is shown in Figure 1. The sorbent film synthesized from C2H4-CVD had higher CNT density and was a stronger sorbent. In general, the CNT microtraps showed high-capacity adsorption and fast quantitative desorption, and the process achieved excellent precision (relative standard deviation below 2%). This study demonstrates that CNT films can be deposited quite easily in capillary structures for the use in different analytical applications.
Another important aspect of this research project is the chemical functionalization of CNTs to change their adsorption characteristics for use in sensing applications. Typically, CNTs are chemically inert and chemical modification is difficult. A novel microwave-induced chemical functionalization technique has been developed during this reporting period. The major advantage of this high-energy procedure is that it reduces the reaction time (to minutes) and the number of steps in the reaction procedure compared to that of conventional functionalization processes. Two successful modifications, namely amidation and 1,3-dipolar cycloaddition of single-walledl nanotubes (SWNTs) were carried out. The amidation was completed in two steps as compared to three in the conventional approach. The step involving acid chloride formation was eliminated while the yield remained the same. The 1,3-dipolar cycloaddition of SWNTs was carried out in 15 minutes under microwave conditions, and the results were similar to what was achieved using conventional methods that required 5 days. This finding enables fast and inexpensive processing to produce functional SWNTs, extremely important for their use in real-world applications.
Figure 1. Self-Assembled CNTs in a Microcapillary
Future Activities:
We will focus on the following goals:
- optimization of self-assembly techniques for CNTs;
- chemical functionalization of CNTs;
- separation on CNT sorbents;
- and CNT assembly on microelectromechanical systems structures.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
| Other project views: | All 37 publications | 13 publications in selected types | All 13 journal articles |
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Saridara C, Brukh R, Iqbal Z, Mitra S. Self-assembly carbon nanotubes in a microtrap for on-line preconcentration of volatile organics. Abstracts of Papers of the American Chemical Society (in press ,2005); IEC Pt 1 (229): 188. |
R830901 (2004) |
not available |
Supplemental Keywords:
carbon nanotubes, single wall nanotubes, chemical functionalization, microtrap, VOCs, volatile organic carbon, aerosol analyzers, air pollution, environmental contaminants, geometric catalytic selectivity,, Sustainable Industry/Business, RFA, Air, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, Engineering, Chemistry, & Physics, Chemistry and Materials Science, Monitoring/Modeling, New/Innovative technologies, Environmental Engineering, Environmental Monitoring, micro integrated sensinig system, environmental measurement, carbon nanotubes, nanotechnology, nanoengineering, micro electromechanical system, aerosol analyzers, nanocrystals, geometric catalytic selectivity, nanoparticle catalysts, air pollution, air pollution controlProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.