1
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Li M, Su H, Zheng G, Kuhn U, Kim N, Li G, Ma N, Pöschl U, Cheng Y. Aerosol pH and Ion Activities of HSO 4- and SO 42- in Supersaturated Single Droplets. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:12863-12872. [PMID: 36047919 PMCID: PMC9494740 DOI: 10.1021/acs.est.2c01378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 08/23/2022] [Accepted: 08/25/2022] [Indexed: 06/15/2023]
Abstract
Accurate determination of acidity (pH) and ion activities in aqueous droplets is a major experimental and theoretical challenge for understanding and simulating atmospheric multiphase chemistry. Here, we develop a ratiometric Raman spectroscopy method to measure the equilibrium concentration of sulfate (SO42-) and bisulfate (HSO4-) in single microdroplets levitated by aerosol optical tweezers. This approach enables determination of ion activities and pH in aqueous sodium bisulfate droplets under highly supersaturated conditions. The experimental results were compared against aerosol thermodynamic model calculations in terms of simulating aerosol ion concentrations, ion activity coefficients, and pH. We found that the Extended Aerosol Inorganics Model (E-AIM) can well reproduce the experimental results. The alternative model ISORROPIA, however, exhibits substantial deviations in SO42- and HSO4- concentrations and up to a full unit of aerosol pH under acidic conditions, mainly due to discrepancies in simulating ion activity coefficients of SO42--HSO4- equilibrium. Globally, this may cause an average deviation of ISORROPIA from E-AIM by 25 and 65% in predicting SO42- and HSO4- concentrations, respectively. Our results show that it is important to determine aerosol pH and ion activities in the investigation of sulfate formation and related aqueous phase chemistry.
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Affiliation(s)
- Meng Li
- Minerva
Research Group, Max Planck Institute for
Chemistry, 55128 Mainz, Germany
| | - Hang Su
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Guangjie Zheng
- Minerva
Research Group, Max Planck Institute for
Chemistry, 55128 Mainz, Germany
| | - Uwe Kuhn
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Najin Kim
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Guo Li
- Minerva
Research Group, Max Planck Institute for
Chemistry, 55128 Mainz, Germany
| | - Nan Ma
- Minerva
Research Group, Max Planck Institute for
Chemistry, 55128 Mainz, Germany
- Institute
for Environmental and Climate Research, Jinan University, Guangzhou 511443, China
| | - Ulrich Pöschl
- Multiphase
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Yafang Cheng
- Minerva
Research Group, Max Planck Institute for
Chemistry, 55128 Mainz, Germany
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2
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Chang YP, Devi Y, Chen CH. Micro-droplet Trapping and Manipulation: Understanding Aerosol Better for a Healthier Environment. Chem Asian J 2021; 16:1644-1660. [PMID: 33999498 DOI: 10.1002/asia.202100516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Indexed: 11/09/2022]
Abstract
Understanding the physicochemical properties and heterogeneous processes of aerosols is key not only to elucidate the impacts of aerosols on the atmosphere and humans but also to exploit their further applications, especially for a healthier environment. Experiments that allow for spatially control of single aerosol particles and investigations on the fundamental properties and heterogeneous chemistry at the single-particle level have flourished during the last few decades, and significant breakthroughs in recent years promise better control and novel applications aimed at resolving key issues in aerosol science. Here we propose graphene oxide (GO) aerosols as prototype aerosols containing polycyclic aromatic hydrocarbons, and GO can behave as two-dimensional surfactants which could modify the interfacial properties of aerosols. We describe the techniques of trapping single particles and furthermore the current status of the optical spectroscopy and chemistry of GO. The current applications of these single-particle trapping techniques are summarized and interesting future applications of GO aerosols are discussed.
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Affiliation(s)
- Yuan-Pin Chang
- Department of Chemistry, National Sun Yat-sen University, No. 70 Lien-hai Rd., Kaohsiung, 80424, Taiwan.,Aerosol Science Research Center, National Sun Yat-sen University, No. 70 Lien-hai Rd., Kaohsiung, 80424, Taiwan
| | - Yanita Devi
- Department of Chemistry, National Sun Yat-sen University, No. 70 Lien-hai Rd., Kaohsiung, 80424, Taiwan
| | - Chun-Hu Chen
- Department of Chemistry, National Sun Yat-sen University, No. 70 Lien-hai Rd., Kaohsiung, 80424, Taiwan
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3
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McGloin D. Droplet lasers: a review of current progress. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:054402. [PMID: 28218616 DOI: 10.1088/1361-6633/aa6172] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
It is perhaps surprising that something as fragile as a microscopic droplet could possibly form a laser. In this article we will review some of the underpinning physics as to how this might be possible, and then examine the state of the art in the field. The technology to create and manipulate droplets will be examined, as will the different classes of droplet lasers. We discuss the rapidly developing fields of droplet biolasers, liquid crystal laser droplets and explore how droplet lasers could give rise to new bio and chemical sensing and analysis. The challenges that droplet lasers face in becoming robust devices, either as sensors or as photonic components in the lab on chip devices, is assessed.
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Affiliation(s)
- D McGloin
- SUPA, School of Science and Engineering, University of Dundee, Dundee DD1 4HN, United Kingdom
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4
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Haddrell AE, Miles REH, Bzdek BR, Reid JP, Hopkins RJ, Walker JS. Coalescence Sampling and Analysis of Aerosols using Aerosol Optical Tweezers. Anal Chem 2017; 89:2345-2352. [DOI: 10.1021/acs.analchem.6b03979] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Allen E. Haddrell
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | | | - Bryan R. Bzdek
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Jonathan P. Reid
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Rebecca J. Hopkins
- Defence Science and Technology Laboratory (DSTL), Porton Down, Salisbury SP4 0JQ, United Kingdom
| | - Jim S. Walker
- Bristol Industrial and Research Associates Ltd (BIRAL), Unit 8 Harbour Road Trading Estate, Portishead, Bristol BS20 7BL, United Kingdom
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5
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Bzdek BR, Collard L, Sprittles JE, Hudson AJ, Reid JP. Dynamic measurements and simulations of airborne picolitre-droplet coalescence in holographic optical tweezers. J Chem Phys 2017; 145:054502. [PMID: 27497560 DOI: 10.1063/1.4959901] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We report studies of the coalescence of pairs of picolitre aerosol droplets manipulated with holographic optical tweezers, probing the shape relaxation dynamics following coalescence by simultaneously monitoring the intensity of elastic backscattered light (EBL) from the trapping laser beam (time resolution on the order of 100 ns) while recording high frame rate camera images (time resolution <10 μs). The goals of this work are to: resolve the dynamics of droplet coalescence in holographic optical traps; assign the origin of key features in the time-dependent EBL intensity; and validate the use of the EBL alone to precisely determine droplet surface tension and viscosity. For low viscosity droplets, two sequential processes are evident: binary coalescence first results from the overlap of the optical traps on the time scale of microseconds followed by the recapture of the composite droplet in an optical trap on the time scale of milliseconds. As droplet viscosity increases, the relaxation in droplet shape eventually occurs on the same time scale as recapture, resulting in a convoluted evolution of the EBL intensity that inhibits quantitative determination of the relaxation time scale. Droplet coalescence was simulated using a computational framework to validate both experimental approaches. The results indicate that time-dependent monitoring of droplet shape from the EBL intensity allows for robust determination of properties such as surface tension and viscosity. Finally, the potential of high frame rate imaging to examine the coalescence of dissimilar viscosity droplets is discussed.
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Affiliation(s)
- Bryan R Bzdek
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Liam Collard
- Department of Mathematics, University of Leicester, Leicester LE1 7RH, United Kingdom
| | - James E Sprittles
- Mathematics Institute, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Andrew J Hudson
- Department of Chemistry, University of Leicester, Leicester LE1 7RH, United Kingdom
| | - Jonathan P Reid
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
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6
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Song YC, Haddrell AE, Bzdek BR, Reid JP, Bannan T, Topping DO, Percival C, Cai C. Measurements and Predictions of Binary Component Aerosol Particle Viscosity. J Phys Chem A 2016; 120:8123-8137. [DOI: 10.1021/acs.jpca.6b07835] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Young Chul Song
- School
of Chemistry, University of Bristol, Bristol, BS8 1TS, United Kingdom
| | - Allen E. Haddrell
- School
of Chemistry, University of Bristol, Bristol, BS8 1TS, United Kingdom
| | - Bryan R. Bzdek
- School
of Chemistry, University of Bristol, Bristol, BS8 1TS, United Kingdom
| | - Jonathan P. Reid
- School
of Chemistry, University of Bristol, Bristol, BS8 1TS, United Kingdom
| | - Thomas Bannan
- School
of Earth, Atmospheric and Environmental Science, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - David O. Topping
- School
of Earth, Atmospheric and Environmental Science, University of Manchester, Manchester, M13 9PL, United Kingdom
- National
Centre for Atmospheric Science, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Carl Percival
- School
of Earth, Atmospheric and Environmental Science, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Chen Cai
- The
Institute of Chemical Physics, Key Laboratory of Cluster Science, Beijing Institute of Technology, Beijing 100081, People’s Republic of China
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7
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Bzdek BR, Power RM, Simpson SH, Reid JP, Royall CP. Precise, contactless measurements of the surface tension of picolitre aerosol droplets. Chem Sci 2015; 7:274-285. [PMID: 28758004 PMCID: PMC5515047 DOI: 10.1039/c5sc03184b] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 10/02/2015] [Indexed: 01/25/2023] Open
Abstract
Precise measurements of the surface tension and viscosity of airborne picolitre droplets can be accomplished using holographic optical tweezers.
The surface composition and surface tension of aqueous droplets can influence key aerosol characteristics and processes including the critical supersaturation required for activation to form cloud droplets in the atmosphere. Despite its fundamental importance, surface tension measurements on droplets represent a considerable challenge owing to their small volumes. In this work, we utilize holographic optical tweezers to study the damped surface oscillations of a suspended droplet (<10 μm radius) following the controlled coalescence of a pair of droplets and report the first contactless measurements of the surface tension and viscosity of droplets containing only 1–4 pL of material. An advantage of performing the measurement in aerosol is that supersaturated solute states (common in atmospheric aerosol) may be accessed. For pairs of droplets starting at their equilibrium surface composition, surface tensions and viscosities are consistent with bulk equilibrium values, indicating that droplet surfaces respond to changes in surface area on microsecond timescales and suggesting that equilibrium values can be assumed for growing atmospheric droplets. Furthermore, droplet surfaces are shown to be rapidly modified by trace species thereby altering their surface tension. This equilibration of droplet surface tension to the local environmental conditions is illustrated for unknown contaminants in laboratory air and also for droplets exposed to gas passing through a water–ethanol solution. This approach enables precise measurements of surface tension and viscosity over long time periods, properties that currently are poorly constrained.
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Affiliation(s)
- Bryan R Bzdek
- School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK .
| | - Rory M Power
- School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK . .,Max Planck Institute of Molecular Cell Biology and Genetics , Dresden , 01307 , Germany
| | - Stephen H Simpson
- School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK . .,Institute of Scientific Instruments of the ASCR. v.v.i. , Krávolopolská 147 , 612 64 , Brno , Czech Republic
| | - Jonathan P Reid
- School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK .
| | - C Patrick Royall
- School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK . .,H. H. Wills Physics Laboratory , University of Bristol , Bristol , BS8 1TL , UK.,Centre for Nanoscience and Quantum Information , University of Bristol , BS8 1FD , UK
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8
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Redding B, Schwab M, Pan YL. Raman Spectroscopy of Optically Trapped Single Biological Micro-Particles. SENSORS 2015; 15:19021-46. [PMID: 26247952 PMCID: PMC4570358 DOI: 10.3390/s150819021] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 06/30/2015] [Accepted: 07/27/2015] [Indexed: 12/20/2022]
Abstract
The combination of optical trapping with Raman spectroscopy provides a powerful method for the study, characterization, and identification of biological micro-particles. In essence, optical trapping helps to overcome the limitation imposed by the relative inefficiency of the Raman scattering process. This allows Raman spectroscopy to be applied to individual biological particles in air and in liquid, providing the potential for particle identification with high specificity, longitudinal studies of changes in particle composition, and characterization of the heterogeneity of individual particles in a population. In this review, we introduce the techniques used to integrate Raman spectroscopy with optical trapping in order to study individual biological particles in liquid and air. We then provide an overview of some of the most promising applications of this technique, highlighting the unique types of measurements enabled by the combination of Raman spectroscopy with optical trapping. Finally, we present a brief discussion of future research directions in the field.
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Affiliation(s)
- Brandon Redding
- U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, MD 20783, USA.
| | - Mark Schwab
- U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, MD 20783, USA.
| | - Yong-le Pan
- U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, MD 20783, USA.
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9
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Power RM, Burnham DR, Reid JP. Toward optical-tweezers-based force microscopy for airborne microparticles. APPLIED OPTICS 2014; 53:8522-8534. [PMID: 25608202 DOI: 10.1364/ao.53.008522] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Optical tweezers have found widespread application in biological and colloidal physics for the measurement of pN forces over nanometer to micrometer length scales. Similar aerosol-phase measurements of interparticle force have not been reported in spite of the potential to better resolve particle coagulation kinetics. Various refractive index mismatches in the beam path as well as the need to explicitly account for gravity and inertial particle motion provide a number of challenges that must be overcome to make such measurements tractable. In this regard, we demonstrate schemes by which the particle position and trap stiffness may be unambiguously measured using bright-field microscopy with resolution comparable with analogous condensed-phase measurements. Moreover, some of the challenges of working with highly dynamic aqueous particles are introduced and exploited to observe size-dependent phenomena in aerosol optical tweezers. Notably, when combined with cavity-enhanced Raman spectroscopy, this provides a unique opportunity to explore trapping forces over a continuum of particle size and refractive index. It is expected that the methods developed will provide a basis for the measurement of pairwise interaction forces in aerosol optical tweezers while providing a probe of fundamental airborne particle trapping dynamics.
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10
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Power RM, Reid JP. Probing the micro-rheological properties of aerosol particles using optical tweezers. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2014; 77:074601. [PMID: 24994710 DOI: 10.1088/0034-4885/77/7/074601] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The use of optical trapping techniques to manipulate probe particles for performing micro-rheological measurements on a surrounding fluid is well-established. Here, we review recent advances made in the use of optical trapping to probe the rheological properties of trapped particles themselves. In particular, we review observations of the continuous transition from liquid to solid-like viscosity of sub-picolitre supersaturated solution aerosol droplets using optical trapping techniques. Direct measurements of the viscosity of the particle bulk are derived from the damped oscillations in shape following coalescence of two particles, a consequence of the interplay between viscous and surface forces and the capillary driven relaxation of the approximately spheroidal composite particle. Holographic optical tweezers provide a facile method for the manipulation of arrays of particles allowing coalescence to be controllably induced between two micron-sized aerosol particles. The optical forces, while sufficiently strong to confine the composite particle, are several orders of magnitude weaker than the capillary forces driving relaxation. Light, elastically back-scattered by the particle, is recorded with sub-100 ns resolution allowing measurements of fast relaxation (low viscosity) dynamics, while the brightfield image can be used to monitor the shape relaxation extending to times in excess of 1000 s. For the slowest relaxation dynamics studied (particles with the highest viscosity) the presence and line shape of whispering gallery modes in the cavity enhanced Raman spectrum can be used to infer the relaxation time while serving the dual purpose of allowing the droplet size and refractive index to be measured with accuracies of ±0.025% and ±0.1%, respectively. The time constant for the damped relaxation can be used to infer the bulk viscosity, spanning from the dilute solution limit to a value approaching that of a glass, typically considered to be >10(12) Pa s, whilst the frequencies of the normal modes of the oscillations of the particle can be used to infer surface properties. We will review the use of optical tweezers for studying the viscosity of aerosol particles and discuss the potential use of this micro-rheological tool for probing the fundamental concepts of phase, thermodynamic equilibrium and metastability.
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Affiliation(s)
- Rory M Power
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK
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11
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Anand S, Nylk J, Neale SL, Dodds C, Grant S, Ismail MH, Reboud J, Cooper JM, McGloin D. Aerosol droplet optical trap loading using surface acoustic wave nebulization. OPTICS EXPRESS 2013; 21:30148-30155. [PMID: 24514593 DOI: 10.1364/oe.21.030148] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We demonstrate the use of surface acoustic wave nebulization (SAWN) to load optical traps. We show that the droplets sizes produced can be tuned by altering the RF frequency applied to the devices, which leads to more control over the sizes of trapped particles. Typically the size distribution of the liquid aerosols delivered using SAWN is smaller than via a standard commercial nebulization device. The ability to trap a range of liquids or small solid particles, not readily accessible using other ultrasonic devices, is also demonstrated both in optical tweezers and dual beam fiber traps.
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12
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Brzobohatý O, Šiler M, Ježek J, Jákl P, Zemánek P. Optical manipulation of aerosol droplets using a holographic dual and single beam trap. OPTICS LETTERS 2013; 38:4601-4604. [PMID: 24322084 DOI: 10.1364/ol.38.004601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present optical trapping and manipulation of pure water and salt water airborne droplets of various sizes ranging from sub-micrometers up to several tens of micrometers in a holographic dual and single beam trap. In the dual beam trap, successful fusion of droplets as well as precise delivery of many droplets and manipulation of multiple droplets are demonstrated. Furthermore, employing the transfer of the orbital angular momentum of light from Laguerre-Gaussian beams, we show that the water droplets orbit around the beam propagation axis and their tangential speed can be controlled by beam waist magnitude. We also demonstrate that sub-micrometer sized pure water droplets can be trapped and manipulated by a single beam trap with a relatively low numerical aperture. In this case, multiple stable trapping positions were observed, both theoretically and experimentally, which were due to the optical intensity oscillations in the focal region of the laser beam.
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13
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Power R, Reid JP, Anand S, McGloin D, Almohamedi A, Mistry NS, Hudson AJ. Observation of the Binary Coalescence and Equilibration of Micrometer-Sized Droplets of Aqueous Aerosol in a Single-Beam Gradient-Force Optical Trap. J Phys Chem A 2012; 116:8873-84. [DOI: 10.1021/jp304929t] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- R. Power
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol,
BS8 1TS, United Kingdom
| | - J. P. Reid
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol,
BS8 1TS, United Kingdom
| | - S. Anand
- Electronic Engineering and Physics
Division, University of Dundee, Dundee,
DD1 4HN, United Kingdom
| | - D. McGloin
- Electronic Engineering and Physics
Division, University of Dundee, Dundee,
DD1 4HN, United Kingdom
| | - A. Almohamedi
- Department
of Physics, University of Leicester, Leicester,
LE1 7RH, United
Kingdom
| | - N. S. Mistry
- Department of Chemistry, University of Leicester, Leicester, LE1 7RH, United
Kingdom
| | - A. J. Hudson
- Department of Chemistry, University of Leicester, Leicester, LE1 7RH, United
Kingdom
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14
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Horstmann M, Probst K, Fallnich C. Towards an integrated optical single aerosol particle lab. LAB ON A CHIP 2012; 12:295-301. [PMID: 22105700 DOI: 10.1039/c1lc20467j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present a manipulation and characterization system for single airborne particles which is integrated onto a microscope slide. Trapped particles are manipulated by means of radiation pressure and characterized by cavity enhanced Raman spectroscopy. Optical fibers are used to deliver the trapping laser light as well as to collect the Raman scattered light, allowing for a flexible usage of the device. The system features a sample chamber which is separated from an aerosol-flooded injection chamber by means of a light guiding glass-capillary. The coupling of this device with an aerosol optical tweezers setup to selectively load its trapping sites is demonstrated. Finally, a route towards chip-integrated handling and processing of multiple particles is shown and the first results are presented.
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Affiliation(s)
- Marcel Horstmann
- Institute of Applied Physics, Westfälische Wilhelms-Universität Münster, Corrensstr. 2, 48149 Münster, Germany.
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15
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Krieger UK, Marcolli C, Reid JP. Exploring the complexity of aerosol particle properties and processes using single particle techniques. Chem Soc Rev 2012; 41:6631-62. [DOI: 10.1039/c2cs35082c] [Citation(s) in RCA: 247] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Pompano RR, Liu W, Du W, Ismagilov RF. Microfluidics using spatially defined arrays of droplets in one, two, and three dimensions. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2011; 4:59-81. [PMID: 21370983 DOI: 10.1146/annurev.anchem.012809.102303] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Spatially defined arrays of droplets differ from bulk emulsions in that droplets in arrays can be indexed on the basis of one or more spatial variables to enable identification, monitoring, and addressability of individual droplets. Spatial indexing is critical in experiments with hundreds to millions of unique compartmentalized microscale processes--for example, in applications such as digital measurements of rare events in a large sample, high-throughput time-lapse studies of the contents of individual droplets, and controlled droplet-droplet interactions. This review describes approaches for spatially organizing and manipulating droplets in one-, two-, and three-dimensional structured arrays, including aspiration, laminar flow, droplet traps, the SlipChip, self-assembly, and optical or electrical fields. This review also presents techniques to analyze droplets in arrays and applications of spatially defined arrays, including time-lapse studies of chemical, enzymatic, and cellular processes, as well as further opportunities in chemical, biological, and engineering sciences, including perturbation/response experiments and personal and point-of-care diagnostics.
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Affiliation(s)
- Rebecca R Pompano
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
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17
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Lall AA, Terray A, Hart SJ. On-the-fly cross flow laser guided separation of aerosol particles based on size, refractive index and density-theoretical analysis. OPTICS EXPRESS 2010; 18:26775-26790. [PMID: 21196954 DOI: 10.1364/oe.18.026775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Laser separation of particles is achieved using forces resulting from the momentum exchange between particles and photons constituting the laser radiation. Particles can experience different optical forces depending on their size and/or optical properties, such as refractive index. Thus, particles can move at different speeds in the presence of an optical force, leading to spatial separations. In this paper, we present a theoretical analysis on laser separation of non-absorbing aerosol particles moving at speeds (1-10 cm/sec) which are several orders of magnitude greater than typical particle speeds used in previous studies in liquid medium. The calculations are presented for particle deflection by a loosely focused Gaussian 1064 nm laser, which simultaneously holds and deflects particles entrained in flow perpendicular to their direction of travel. The gradient force holds the particles against the viscous drag for a short period of time. The scattering force simultaneously pushes the particles, perpendicular to the flow, during this period. Our calculations show particle deflections of over 2500 µm for 15 µm aerosol particles, and a separation of over 1500 µm between 5 µm and 10 µm particles when the laser is operated at 10 W. We show that a separation of about 421 µm can be achieved between two particles of the same size (10 µm) but having a refractive index difference of 0.1. Density based separations are also possible. Two 10 µm particles with a density difference of 600 kg/m3 can be separated by 193 µm. Examples are shown for separation distances between polystyrene, poly(methylmethacrylate), silica and water particles. These large laser guided deflections represent a novel achievement for optical separation in the gas phase.
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Affiliation(s)
- A A Lall
- Excet, Inc., Springfield, Virginia, USA
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18
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Walker JS, Wills JB, Reid JP, Wang L, Topping DO, Butler JR, Zhang YH. Direct Comparison of the Hygroscopic Properties of Ammonium Sulfate and Sodium Chloride Aerosol at Relative Humidities Approaching Saturation. J Phys Chem A 2010; 114:12682-91. [DOI: 10.1021/jp107802y] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jim S. Walker
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K., School of Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, P. R. China, and School of Earth, Atmospheric and Environmental Sciences, Williamson Building, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Jon B. Wills
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K., School of Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, P. R. China, and School of Earth, Atmospheric and Environmental Sciences, Williamson Building, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Jonathan P. Reid
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K., School of Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, P. R. China, and School of Earth, Atmospheric and Environmental Sciences, Williamson Building, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Liangyu Wang
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K., School of Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, P. R. China, and School of Earth, Atmospheric and Environmental Sciences, Williamson Building, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - David O. Topping
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K., School of Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, P. R. China, and School of Earth, Atmospheric and Environmental Sciences, Williamson Building, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Jason R. Butler
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K., School of Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, P. R. China, and School of Earth, Atmospheric and Environmental Sciences, Williamson Building, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Yun-Hong Zhang
- School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K., School of Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, P. R. China, and School of Earth, Atmospheric and Environmental Sciences, Williamson Building, University of Manchester, Oxford Road, Manchester M13 9PL, U.K
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Probing the Equilibrium Size and Hydrogen Bonding Structure in Aqueous Aerosol Droplets. ACTA ACUST UNITED AC 2010. [DOI: 10.1524/zpch.2010.6147] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
Comparative measurements on two or more optically trapped aerosol droplets can allow the hygroscopic properties of aerosol to be investigated in exquisite detail. In this paper we consider two methods for assessing the dependence on relative humidity of the water activity and solute concentration in the condensed phase. We demonstrate in this paper that using a control droplet as a microprobe of relative humidity in the vicinity of a second droplet of interest can allow the RH to be determined with an accuracy of between 0.01 to 0.1 %. Not only is such a probe highly responsive, but the accuracy of the RH determination improves with increase in GF or RH, counter to the performance of macroscopic RH probes. We also demonstrate that spontaneous Raman scattering recorded from excitation of the OH stretching vibration in supersaturated solution droplets of sodium chloride shows the considerable perturbation induced by the chloride ion on the hydrogen bonding network. Chloride is recognised as a hydrogen bonding structure breaker and these observations are shown to be consistent with measurements on more dilute solutions.
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Hargreaves G, Kwamena NOA, Zhang YH, Butler JR, Rushworth S, Clegg SL, Reid JP. Measurements of the Equilibrium Size of Supersaturated Aqueous Sodium Chloride Droplets at Low Relative Humidity Using Aerosol Optical Tweezers and an Electrodynamic Balance. J Phys Chem A 2010; 114:1806-15. [DOI: 10.1021/jp9095985] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- G. Hargreaves
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, U.K.; School of Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, P. R. China; and School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, U.K
| | - N.-O. A. Kwamena
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, U.K.; School of Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, P. R. China; and School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, U.K
| | - Y. H. Zhang
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, U.K.; School of Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, P. R. China; and School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, U.K
| | - J. R. Butler
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, U.K.; School of Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, P. R. China; and School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, U.K
| | - S. Rushworth
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, U.K.; School of Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, P. R. China; and School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, U.K
| | - S. L. Clegg
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, U.K.; School of Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, P. R. China; and School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, U.K
| | - J. P. Reid
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, U.K.; School of Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, P. R. China; and School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, U.K
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Wills JB, Butler JR, Palmer J, Reid JP. Using optical landscapes to control, direct and isolate aerosol particles. Phys Chem Chem Phys 2009; 11:8015-20. [DOI: 10.1039/b908270k] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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