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Photothermal Spectroscopy Utilizing Miniature Sensors for Chemical Sensing.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Photothermal Spectroscopy Utilizing Miniature Sensors for Chemical Sensing./
Author:	Zhao, Yaoli.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2024,
Description:	213 p.
Notes:	Source: Dissertations Abstracts International, Volume: 85-08, Section: B.
Contained By:	Dissertations Abstracts International85-08B.
Subject:	Chemical engineering. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30989117
ISBN:	9798381698046

Photothermal Spectroscopy Utilizing Miniature Sensors for Chemical Sensing.
Zhao, Yaoli.

Photothermal Spectroscopy Utilizing Miniature Sensors for Chemical Sensing. - Ann Arbor : ProQuest Dissertations & Theses, 2024 - 213 p.

Source: Dissertations Abstracts International, Volume: 85-08, Section: B.

Thesis (Ph.D.)--State University of New York at Buffalo, 2024.

This item must not be sold to any third party vendors.

Chemical sensors are devices that transform chemical information such as chemical concentration, composition, and activity into an analytically useful electrical signal. These sensors hold significant applications across diverse fields, including environmental monitoring, plastic recycling, agriculture, defense and safety, mining, food production, bioengineering, and medical diagnostics. The performance of these chemical sensors is evaluated using definable metrics such as sensitivity, selectivity, resolution, and response and recovery times. Advances in the fabrication of miniaturized mechanical structures for sensing, such as microcantilevers, have dramatically enhanced sensitivities by several orders of magnitude. However, challenges still exist in achieving the required selectivity and response time required for industrial use of microsensors.{A0}Selectivity is one of the most important characteristics of a chemical sensor, and it refers to the ability of the sensor to differentiate target analyte in the presence of other chemical species with similar molecular properties. Conventional molecular recognition methods, based on room temperature reversible adsorption on immobilized chemical interfaces (receptors) on sensor surfaces, often suffer from poor selectivity due to the generic nature of weak chemical interactions such as hydrogen bonds or van der Waal forces. To overcome this, recent attempts have focused on combining Infrared (IR) spectroscopy with microsensors to achieve the desired selectivity. This approach aims to enhance chemical sensors' sensitivity and selectivity simultaneously by combining the high thermal sensitivity of microfabricated structures with the unique molecular selectivity offered by mid-IR spectroscopy.{A0}In this thesis, a microfabricated nanoscale thermocouple junction incorporated at the apex of a microcantilever was used as a thermal sensor. The analyte molecules adsorbed on the thermocouple{A0}junction generate heat when resonantly excited with infrared red radiation due to nonradiative decay. Using this method, the detection of photothermal spectra of physisorbed trinitrotoluene (TNT) and dimethyl methylphosphonate (DMMP) molecules, as well as representative polymers, with an estimated mass of 10-18 g is demonstrated.Standoff chemical detection techniques have significant applications across several fields and can be exploited for demanding practical tasks such as efficient sorting of plastics for recycling. In this context, a bimaterial cantilever is used as an IR detector for IR radiation scattered off a target sample placed at a distance. A plot of cantilever deflection as a function of the wavelength of tunable IR radiation scattered by the target sample reveals its spectrum. Photothermal cantilever deflection spectroscopy (PCDS) carried out in a standoff manner presents a reliable method for discerning materials from a distance with exceptional molecular sensitivity and selectivity. This thesis demonstrates PCDS as a sensitive and selective technique for standoff detection of plastic waste samples and thin polymer films. Chemical signatures for different types of pure and mixed plastic waste samples, including those with additives and surface contaminants, were successfully detected and discerned. Analysis of the standoff spectral data, using machine learning algorithms, showed 100% accuracy in selectively identifying real-world plastic waste according to their respective resin identification codes. PCDS is also demonstrated to accurately detect and discriminate between various thin polymer films such as PMMA, PVA, and SU8. Spectra obtained in the present work show excellent agreement with conventional FTIR spectra.{A0}Although standoff detection using mid-infrared radiation offers outstanding molecular selectivity, sensitive detection of mid-IR radiation using cost-effective detectors remains a challenge. In this thesis, the viability of utilizing a commercially available and cost-effective quartz tuning fork (QTF) for standoff detection of solid samples using mid-IR radiation is demonstrated. The IR{A0}absorption spectra obtained by QTF when compared with those acquired by ATR-FTIR and microcantilever-based PCDS, reveal superior spectral resolution for the former. With the integration of simple machine learning algorithms with QTF thermoelastic IR spectra, it is shown that various plastic samples can be effectively classified with 100% accuracy. Furthermore, this method proves to be useful for the identification of black plastics, eliminating the need for additional sample preparation.Finally, the thesis demonstrates the use of the PCDS technique for the selective and sensitive detection of analytes in the gas phase, including CO2, CH4, NH3, and volatile organic compounds such as benzene, toluene, and xylene. In this method, gas molecules undergo physisorption on a bimaterial cantilever surface and subsequently are exposed to mid-IR radiation from a tunable IR source. The resonant vibrational excitation of the adsorbed molecules and following nonradiative decay processes induce a temperature increase and result in a measurable deflection of the bimaterial cantilever. The nanomechanical deflection of the cantilever, dependent on the illumination wavelength, corresponds to the unique IR absorption spectrum of the adsorbed gas molecules. Additionally, resonance frequency measurements are performed to estimate the mass of physisorbed molecules on the cantilever surface. These findings demonstrate the potential of PCDS for the detection and molecular discrimination of various gas phase analytes at ppm level.

ISBN: 9798381698046Subjects--Topical Terms:

560457
Chemical engineering.
Subjects--Index Terms:

Infrared spectroscopy

Photothermal Spectroscopy Utilizing Miniature Sensors for Chemical Sensing.
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245 1 0 $a Photothermal Spectroscopy Utilizing Miniature Sensors for Chemical Sensing.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2024
300 $a 213 p.
500 $a Source: Dissertations Abstracts International, Volume: 85-08, Section: B.
500 $a Advisor: Thundat, Thomas.
502 $a Thesis (Ph.D.)--State University of New York at Buffalo, 2024.
506 $a This item must not be sold to any third party vendors.
520 $a Chemical sensors are devices that transform chemical information such as chemical concentration, composition, and activity into an analytically useful electrical signal. These sensors hold significant applications across diverse fields, including environmental monitoring, plastic recycling, agriculture, defense and safety, mining, food production, bioengineering, and medical diagnostics. The performance of these chemical sensors is evaluated using definable metrics such as sensitivity, selectivity, resolution, and response and recovery times. Advances in the fabrication of miniaturized mechanical structures for sensing, such as microcantilevers, have dramatically enhanced sensitivities by several orders of magnitude. However, challenges still exist in achieving the required selectivity and response time required for industrial use of microsensors.{A0}Selectivity is one of the most important characteristics of a chemical sensor, and it refers to the ability of the sensor to differentiate target analyte in the presence of other chemical species with similar molecular properties. Conventional molecular recognition methods, based on room temperature reversible adsorption on immobilized chemical interfaces (receptors) on sensor surfaces, often suffer from poor selectivity due to the generic nature of weak chemical interactions such as hydrogen bonds or van der Waal forces. To overcome this, recent attempts have focused on combining Infrared (IR) spectroscopy with microsensors to achieve the desired selectivity. This approach aims to enhance chemical sensors' sensitivity and selectivity simultaneously by combining the high thermal sensitivity of microfabricated structures with the unique molecular selectivity offered by mid-IR spectroscopy.{A0}In this thesis, a microfabricated nanoscale thermocouple junction incorporated at the apex of a microcantilever was used as a thermal sensor. The analyte molecules adsorbed on the thermocouple{A0}junction generate heat when resonantly excited with infrared red radiation due to nonradiative decay. Using this method, the detection of photothermal spectra of physisorbed trinitrotoluene (TNT) and dimethyl methylphosphonate (DMMP) molecules, as well as representative polymers, with an estimated mass of 10-18 g is demonstrated.Standoff chemical detection techniques have significant applications across several fields and can be exploited for demanding practical tasks such as efficient sorting of plastics for recycling. In this context, a bimaterial cantilever is used as an IR detector for IR radiation scattered off a target sample placed at a distance. A plot of cantilever deflection as a function of the wavelength of tunable IR radiation scattered by the target sample reveals its spectrum. Photothermal cantilever deflection spectroscopy (PCDS) carried out in a standoff manner presents a reliable method for discerning materials from a distance with exceptional molecular sensitivity and selectivity. This thesis demonstrates PCDS as a sensitive and selective technique for standoff detection of plastic waste samples and thin polymer films. Chemical signatures for different types of pure and mixed plastic waste samples, including those with additives and surface contaminants, were successfully detected and discerned. Analysis of the standoff spectral data, using machine learning algorithms, showed 100% accuracy in selectively identifying real-world plastic waste according to their respective resin identification codes. PCDS is also demonstrated to accurately detect and discriminate between various thin polymer films such as PMMA, PVA, and SU8. Spectra obtained in the present work show excellent agreement with conventional FTIR spectra.{A0}Although standoff detection using mid-infrared radiation offers outstanding molecular selectivity, sensitive detection of mid-IR radiation using cost-effective detectors remains a challenge. In this thesis, the viability of utilizing a commercially available and cost-effective quartz tuning fork (QTF) for standoff detection of solid samples using mid-IR radiation is demonstrated. The IR{A0}absorption spectra obtained by QTF when compared with those acquired by ATR-FTIR and microcantilever-based PCDS, reveal superior spectral resolution for the former. With the integration of simple machine learning algorithms with QTF thermoelastic IR spectra, it is shown that various plastic samples can be effectively classified with 100% accuracy. Furthermore, this method proves to be useful for the identification of black plastics, eliminating the need for additional sample preparation.Finally, the thesis demonstrates the use of the PCDS technique for the selective and sensitive detection of analytes in the gas phase, including CO2, CH4, NH3, and volatile organic compounds such as benzene, toluene, and xylene. In this method, gas molecules undergo physisorption on a bimaterial cantilever surface and subsequently are exposed to mid-IR radiation from a tunable IR source. The resonant vibrational excitation of the adsorbed molecules and following nonradiative decay processes induce a temperature increase and result in a measurable deflection of the bimaterial cantilever. The nanomechanical deflection of the cantilever, dependent on the illumination wavelength, corresponds to the unique IR absorption spectrum of the adsorbed gas molecules. Additionally, resonance frequency measurements are performed to estimate the mass of physisorbed molecules on the cantilever surface. These findings demonstrate the potential of PCDS for the detection and molecular discrimination of various gas phase analytes at ppm level.
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650 4 $a Chemical engineering. $3 560457
650 4 $a Applied physics. $3 3343996
650 4 $a Polymer chemistry. $3 3173488
650 4 $a Bioengineering. $3 657580
653 $a Infrared spectroscopy
653 $a Chemical sensors
653 $a Standoff detection
653 $a Polymer films
690 $a 0542
690 $a 0202
690 $a 0215
690 $a 0495
710 2 $a State University of New York at Buffalo. $b Chemical and Biological Engineering. $3 1023676
773 0 $t Dissertations Abstracts International $g 85-08B.
790 $a 0656
791 $a Ph.D.
792 $a 2024
793 $a English
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30989117