Technology
A Different Approach to Sensing
Defiant is not just another sensor company. While other chemical sensors can be overwhelmed by the breadth of chemicals found in the real world, Defiant’s system approach employs a selective, intelligent preconcentration stage to solve difficult sensing problems.
Defiant is not just another sensor company. While other chemical sensors can be overwhelmed by the breadth of chemicals found in the real world, Defiant’s system approach employs a selective, intelligent preconcentration stage to solve difficult sensing problems.
Smart Selective chemical Preconcentration: Defiant uses preconcentrator technology that is capable of sensing when it has collected a sufficient
amount of sample for analysis. If the ambient concentration is low, the device will collect for a longer period of time, if it is high, the collection
time is lowered automatically. In addition, the selective sol gel films used on this device ensure that chemical interferences like diesel and humidity
aren't introduced into the analysis system.
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 As can be seen above, 3 chemicals enter but only 2 are collected. This selectivity can be designed as either a chemical interaction or physical attribute of the device. |
 
Micro Gas Chromatography: Defiant uses a LIGA fabricated GC column that will separate both target and interfering chemicals from one another. In this
fashion, the detector only senses one chemical at a time since the chemicals arrive at the detector at different times. |
 The picture above shows the GC column separating two target chemicals. As they pass through the column, the red chemical is retained longer because it has a higher affinity for the polymer that lines the column. |
 Selective Detection: Defiant uses arrays of surface acoustic wave SAWs detectors and pivot plate resonators (PPRs) as micro-balances. Each element in these arrays can be coated with a variety of different films to provide an array response that is specific to the class of chemical it senses. |
 Since the blue chemical left the GC column first, it reaches the detector first. The red is sensed seconds later. Shown above is a cartoon of our resonator micro-balance which "weighs" the chemical as it passes by the detector. A polymer deposited on the surface promotes sorption of certain chemicals and therefore promotes their detection. |
Think Small
Defiant’s systems are portable and simple to operate.
- Silicon microfabrication creates cost-effective, low power, robust systems.
- Nanomaterials used in our system impart unparalleled sensitivity and selectivity.
- Modular packaging provides easy modifications for our customers and in the field.
Each stage of Defiant's chemical analysis system peels away layers of uncertainty.
- First, the selective preconcentrator ignores interfering chemicals.
- Next, The GC column differentially retains target chemicals.
- Finally, the detector provides a response pattern that is indicative of the class of chemicals
