μ-Integrated Sensing System (μ-ISS) by Controlled Assembly of Carbon Nanotubes on MEMS StructuresEPA Grant Number: R830901
Title: 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 Amount: $346,000
RFA: Environmental Futures Research in Nanoscale Science Engineering and Technology (2002) RFA Text | Recipients Lists
Research Category: Nanotechnology , Safer Chemicals
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 goal of this research is to develop a micro integrated sensing system (m-ISS) on a chip for environmental monitoring.
As materials and devices shrink to the nanoscale, quantum phenomena at these scales become important and can be used to enhance the performance of systems important to environmental analysis. The proposed m-ISS will exploit some of the remarkable nanoscale properties of single wall carbon nanotubes (SWNTs)to provide on-chip concentration via quantum scale adsorption processes, in order to attain the low detection limits necessary for environmental sensing. The integrated system will be fabricated on a chip using micro-electromechanical system (MEMS) technologies, which offer easy miniaturization, and relatively inexpensive mass fabrication.
The m-ISS consists of on-line concentration, separation and detection of organic contaminants. A micromachined pump integrated with the system by silicon micromachining will draw air into the detection system, which will comprise of a sensor array or a chromatographic separation channel along with the sensor array. The proposed sensing scheme will enhance the sensitivity by concentrating the sample on a microconcentrator prior to detection. As the air containing the organics flows through the m-ISS, the pollutants are trapped within the microconcentrator. By heating the microconcentrator to temperatures up to 300°C by an in-channel heater, the organics are desorbed as a concentration pulse into the detection system. When configured with the GC column, the m-ISS serves as a real-time GC system. The microconcentrator and the GC column will be fabricated on the same matrix by self-assembly of SWNT by a chemical vapor deposition (CVD)process developed at NJIT. The SWNT will be functionalized by electrochemical and plasma techniques.
It is anticipated that this project will lead to a sensitive sensing system for near real-time monitoring of volatile organics. The miniature system will be sensitive and cost-effective for mass production. Besides developing the m-ISS, the project will result in several new developments such as CVD self-assembly of SWNTs in microfluidic devices, SWNT as stationary phase in micro-GC columns, and alteration of SWNT selectivity by functionalization.