Performing Department
(N/A)
Non Technical Summary
The drive to improve agricultural output in America has led to many technological advancements in farming machinery, fertilizers, and precision agriculture. Over the past century, these innovations have helped American farms produce the goods necessary to sustain the nation's population growth and consumption demands and have also allowed American agriculture to become more competitive on the global market. However, as the yields of American agriculture have increased, so too has agricultural waste and pollution. Today, chemicals released from agricultural waste are a major contributor to air and water pollution, both domestically and globally. In addition, the high pollution density associated with many of these agricultural enterprises compounded by their copious use of industrial strength cleaning agents, has raised awareness of the potential long and short-term hazards.Ammonia gas, in particular, is one of the principal pollutants threatening air and water quality. Arising from various sources of agricultural and industrial waste, ammonia vapors pose a significant hazard to human health, livestock, crops, and the environment at large. Ammonia is a colorless gas with a strong pungent odor and is typically introduced into the environment from improper waste management, fertilizer overuse, or run-off from industrial strength cleaning agents that are used in agricultural, commercial, industrial, and residential settings. While the severity of health effects depends largely on the dose, duration, and exposure routes, even contact with a small amount of ammonia gas can have serious effects.When ammonia enters the body as a result of inhalation, ingestion, or skin contact (or simply in the presence of water), ammonia can convert to ammonium hydroxide, which is strongly corrosive and toxic. In particular, the lung tissue of both humans and livestock is especially susceptible to ammonia gas and its derivatives. Symptoms ranging from burning of the nostrils, eyes, and respiratory tract are among the milder indicators of ammonia poisoning. Exposure to larger amounts of ammonia gas can be considered a chemical emergency as overexposure can cause blindness and permanent lung damage. As a result, OSHA has set a 50 ppm limit for ammonia exposure over an 8-hour work day and the EPA considers 300 ppm exposure to be immediately threatening to human life.On account of the wide array of agricultural and industrial settings, there is notable diversity in how ammonia vapor pollution is generated, diffuses, and accumulates. Detailed monitoring of this gas-phase pollutant is needed to help mitigate the threats posed by its introduction into our environment and exposure to living organisms. New and improved chemical detection technologies are also needed to simplify and improve the ability to actively and accurately monitor ammonia vapor as it diffuses. Unfortunately, today's commercially available ammonia gas detectors are inadequate, as they rely on expensive, antiquated technology, lack the capacity to remotely monitor and wirelessly report real-time measurements of ammonia levels (i.e. intensity, duration, location, and cumulative load), and are not sufficiently user-friendly to be reasonably operated by non-technical personnel. Moreover, despite the known advantages of wireless connectivity, most ammonia detectors are not equipped with the ability to be connected in a multi-detector wireless detection network. This limitation means that it is difficult to gain an accurate real-time topographical assessment of ammonia pollution as it diffuses across 3-dimensional landscapes. As a result, the true output of ammonia pollution is frequently underestimated, and the sources are more difficult to pinpoint. Due to the potential for harm from air pollutants such as ammonia, the USDA has identified the need for improved detection technologies to help improve air quality.In view of this stated need, Seacoast Science, Inc. proposes the development of a low-cost, portable, gas-phase ammonia detector. Seacoast will leverage a novel class of ammonia-sensitive polymers to develop an ammonia vapor detector that can be integrated into a low-cost, battery powered device with advanced real-time monitoring and wireless networking features. This device will monitor and quantify the intensity and duration of gas-phase ammonia in real-time, maintain a record of the cumulative vapor load, and wirelessly transmit this data to a personal computing device for analysis via software that can be operated with minimal user training. These features will allow each sensor to function as a node in a wireless ammonia detection network to accurately monitor ammonia vapor in real-time across a diverse array of 3-dimensional spatial configurations. In addition, this device will feature an inexpensive, semi-disposable sensing element, strategically designed to be replaced periodically; ensuring high operational performance is maintained while extending device lifetime. Seacoast's proposed ammonia detector will fill the current void in detection capabilities by offering a low-cost, robust, and versatile solution to accurately monitor ammonia pollution across a wide span of agricultural, industrial, and residential settings.
Animal Health Component
30%
Research Effort Categories
Basic
40%
Applied
30%
Developmental
30%
Goals / Objectives
The primary technical objective of this program is to develop a low-cost, high-performance ammonia detector with wireless networking capabilities and a user-friendly software interface. This portable detection device will afford real-time ammonia vapor measurements which improve current capabilities to monitor the presence and/or diffusion of ammonia vapor throughout agricultural landscapes (crops, livestock waste, etc.). In Phase I we seek to validate, as proof-of-concept, that the proposed Lewis Acid Telechelic Polymer (LATP) chemistry integrated with Seacoast's proprietary chemicapacitor and chemiresistor technology will demonstrate the required analytical performance as an ammonia vapor detector to justify further development in Phase II.LATPs offer a promising approach to develop sensitive and selective detector materials for ammonia. The tunable binding of ammonia and/or its analogues to a thin-film of a supramolecular LATP hydrogen-bonded matrix causes a change in the bulk film properties, resulting in a concomitant change that can be monitored via resistance or capacitance measurements. This transformation in properties allows the macromolecular LATP system to be exploited as an ammonia-sensitive transducer. Polymer matrices that can be rationally designed to demonstrate enhanced sensitivity to ammonia-based analytes introduces a new paradigm in gas-phase ammonia detection technology. The natural signal transduction that emerges from the disruption of hydrogen-bonding can be leveraged to enhance sensitivity while simultaneously affording a functional handle which can be utilized to monitor gas-phase ammonia exposure in real-time. As real-time measurements of gas-phase ammonia exposure can be exceedingly difficult to collect, even with research grade analytical instrumentation and experienced technical personnel, the fact that these materials can be used to monitor ammonia vapor in real-time is a highly valuable feature. The use of functional LATP nanomaterials as transducing active layers in MEMS chemicapacitors and chemiresistors also facilitates the miniaturization of real-time, ammonia detection without compromising operational performance.The Phase I experiments will focus on demonstrating the sensitivity and stability of the LATP detection platform with ppm-ppb limits of detection, thermal stability from 20°C - 40°C, and variance <5%. The main focuses of the proof-of-concept study are outlined below:Develop novel ammonia sensitive LATPs,Analyze the use of these LATPs as an ammonia detection platform in a controlled environmental chamber,Identify design rules and methods to rationally improve upon the LATP sensitivity,Outline the steps necessary to develop an advanced prototype for Phase II.The Phase I target is the detection of ammonia vapor in the 5-50 ppm range with sufficient resolving power for subsequent selectivity experiments. Seacoast has the team, infrastructure, and resources in place to successfully deliver on these goals. The sensitivity, lifetime, and ruggedness of this detection system will be further optimized in Phase II and a fully functional advanced prototype will be fabricated.Criteria for Success: The project's success will be demonstrated by our ability to: (1) optimize LATP materials for ammonia detection (2) demonstrate detection of ammonia against likely interferents (H2O, O2, CO2) (3) demonstrate detection of ammonia in a controlled environmental chamber with controlled variable temperature and humidity. (4) elucidate the molecular design rules needed to rationally enhance selectivity and sensitivity of the materials system (5) develop a viable path forward for advanced prototype development for field testing and customer evaluation in Phase II.
Project Methods
The underlying sensing technology of the proposed ammonia detector is based on the use of novel, ammonia-sensitive, LATPs measured by the proprietary MEMS chemicapacitor and chemiresistor; transducers developed at Seacoast. Seacoast has 18 years of experience manufacturing and selling high-performance MEMS-based sensors in addition to the commercial development of advanced functional materials. In Phase I, Seacoast proposes to 1) explore the chemical parameter space of LATP composites - developing the molecular design rules needed to rationally improve their ammonia sensitivity; 2) optimize blend formulations and solution processing conditions for deposition; 3) demonstrate proof-of-concept by testing a functional prototype in ammonia vapor; and 4) outline the development of an advanced prototype equipped with networking capabilities that would be engineered in Phase II. This work is anticipated to lead to the advent of a high-performance, low-cost, gas-phase ammonia detector with advanced wireless networking.The use of LATPs is proposed for the development of a materials system that can be rationally programmed to demonstrate enhanced selectively to ammonia. LATPs are ideal for this application due to their propensity to form supramolecular hydrogen-bonding networks with enhanced affinity for polar protic analytes. The novel LATPs that will be explored in this work are based on a silicone boronate previously prepared by the Brook laboratory, which reversibly crosslinks in the presence of alkyl bisamines (Dodge, et al., 2014). The binding of ammonia and its analogues to a thin-film of a supramolecular hydrogen-bonded matrix causes a change in the bulk film properties, resulting in a concomitant change that can be monitored via resistance or capacitance measurements. This transformation in properties allows the macromolecular LATP system to be exploited as an ammonia-sensitive transducer. In Phase I, the rational design of these LATPs will be explored with a facile and highly modular synthesis, allowing for the rapid screening of analogues via facile modification of the primary reagents. Synthesis will begin with commercially available starting materials and a protocol that is easily amenable to low-cost, high-throughput synthesis of multi-gram batches with no extensive purification techniques required. All synthetic products will be characterized via NMR & Mass Spec.A series of optimized LATP blend formulations will be prepared and solution deposited onto Seacoast's chemiresistor and chemicapacitor arrays. Evaluation of the sensor arrays will be conducted in Seacoast's environmental chamber, which allows sensors to be measured in a testing system that affords fine control over humidity, temperature, and flowrate of multiple analyte vapors. The sensors will be exposed to a variety of polar and non polar vapor interferents to investigate the selectivity of the LATP coated sensors for ammonia vs. interferents. In particular it will be critical to demonstrate molecular contrast between the absorption of ammonia and the primary gas constituents and interferents in air (ie. water, CO2, O2, and N2). Analysis of the ammonia absorption behavior across the family of synthesized LATPs will offer insight into the materials design rules needed to further improve their sensitivity in Phase II. Seacoast will seek to develop rational molecular strategies to further enhance material sensitivity through targeted modifications to the LATP chemical structure.Seacoast will also collect training data to develop calibration algorithm models. This data will be implemented in Phase II software to compensate for environmental variables and to identify and distinguish the principle molecular targets (ie. ammonia vs. interferents - H2O, CO2, O2, N2), first on a PC, then on the prototypes. It is well established that polymer-based sensors can have different peak response ranges commensurate to their HSP values (Eastman, et al., 1999). We will exploit this differing selectivity with pattern recognition algorithms. For example, a low-polarity polyisobutylene chemiresistor has no response to H2O vapor - because H2O does not cause this polymer to swell. In contrast, the high-polarity polyvinylalcohol has a large response to H2O and other polar compounds (Freund, et al. 1995; Patel, et al., 2000). Seacoast will develop preliminary regressions and polynomial fittings to compensate for temperature and humidity variations. This method will be utilized to produce a calibration plot for ammonia, targeting 5-50 ppm limits of detection. A process of repeated testing and measurement taking (ie. multi sampling) of sensor resistance and capacitance will be pursued in order to develop data related to statistical significance.We will develop preliminary designs for an advanced prototype of the ammonia detector; including form factors, size, and weight. Seacoast anticipates the use of fans integrated in the sensor casing to modulate and direct air flow towards the senor to improve the sampling rate and additionally the use of Gore-Tex filter to protect against excess humidity and or errant dust particulates. Such features of the advanced prototype are beyond the scope of Phase I, but will be a major component of our Phase II development. We will also draft an outline of the specific aims, tasks, and success metrics needed to yield a path forward in the Phase II development of advanced prototypes for customer evaluation. Finally, after filing the provisional patent for our technology, we intend to submit a manuscript for publication with results of the materials development and testing to disseminate information as the 1st step to market the product.