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Raheem K, Cassidy J, Betts A, Ryan B. Use of confocal Raman microscopy to characterise ethyl cyanoacrylate adhesive depth curing. Phys Chem Chem Phys 2020; 22:23899-23907. [PMID: 33073814 DOI: 10.1039/d0cp04053c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In situ spatial temporal measurement of monomer conversion during adhesive bondline curing remains a challenging area. The aim of this work was to demonstrate the effectiveness of using confocal Raman microscopy in a specially configured experimental set-up, as a versatile tool for measuring monomer concentration changes as a function of both time and adhesive bond depth during ethyl cyanoacrylate polymerisation. This also allowed monitoring of the extent of polymerisation at the adhesive substrate interface independently of the bulk bondline polymerisation region. Key kinetic parameters such as inhibition time tlag, rate of reaction Rmax and extent of reaction [αt]max were obtained by fitting the experimental data to sigmoidal growth curves using simple piecewise regression models. A systematic characterisation of a polymerisation reaction was conducted using different sample substrate types (copper alloy (red brass), aluminium, aluminium alloy, stainless steel and borosilicate glass) and at various reaction temperatures. Reaction rates were found to decrease further away from the substrate interface in the bulk volume region. The fastest kinetics occurred in the vicinity of nucleophilic hydroxyl rich surfaces such as at the copper alloy (red brass). In addition to substrate surface chemistry, surface roughness was also a factor, with the highest reaction rates occurring with a grit blasted (roughened) aluminium alloy (2024 T3) surface. An approximately linear dependence of the ln Rmaxvs. 1/T (Arrhenius) plot was recorded within the temperature range of 291-328 K. A better fit was obtained however through the use of two separate linear slopes, possibly indicative of a change of polymerisation reaction mechanism taking place at elevated temperatures with two distinct activation energies. Further work conducted using a larger number of temperatures would be useful to verify this finding. This work confirmed that differences in the rates of interfacial and bulk polymerisation processes could be readily measured in situ using confocal Raman microscopy which is a powerful technique for investigating such surface-confined and bulk polymerisation reactions.
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Affiliation(s)
- Kevin Raheem
- Applied Electrochemistry Group, FOCAS Institute, Technological University Dublin, Camden Row, Dublin, Ireland and Chemical and Pharmaceutical Sciences, Technological University Dublin, City Campus, Kevin Street, Dublin, D08NF72, Ireland
| | - John Cassidy
- Applied Electrochemistry Group, FOCAS Institute, Technological University Dublin, Camden Row, Dublin, Ireland and Chemical and Pharmaceutical Sciences, Technological University Dublin, City Campus, Kevin Street, Dublin, D08NF72, Ireland
| | - Anthony Betts
- Applied Electrochemistry Group, FOCAS Institute, Technological University Dublin, Camden Row, Dublin, Ireland and Chemical and Pharmaceutical Sciences, Technological University Dublin, City Campus, Kevin Street, Dublin, D08NF72, Ireland
| | - Bernard Ryan
- Ireland, Henkel, Tallaght Business Park, Whitestown Industrial Estate, Dublin 24, Ireland
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Sharma K, Palatinszky M, Nikolov G, Berry D, Shank EA. Transparent soil microcosms for live-cell imaging and non-destructive stable isotope probing of soil microorganisms. eLife 2020; 9:e56275. [PMID: 33140722 PMCID: PMC7609051 DOI: 10.7554/elife.56275] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Accepted: 10/16/2020] [Indexed: 01/02/2023] Open
Abstract
Microscale processes are critically important to soil ecology and biogeochemistry yet are difficult to study due to soil's opacity and complexity. To advance the study of soil processes, we constructed transparent soil microcosms that enable the visualization of microbes via fluorescence microscopy and the non-destructive measurement of microbial activity and carbon uptake in situ via Raman microspectroscopy. We assessed the polymer Nafion and the crystal cryolite as optically transparent soil substrates. We demonstrated that both substrates enable the growth, maintenance, and visualization of microbial cells in three dimensions over time, and are compatible with stable isotope probing using Raman. We applied this system to ascertain that after a dry-down/rewetting cycle, bacteria on and near dead fungal hyphae were more metabolically active than those far from hyphae. These data underscore the impact fungi have facilitating bacterial survival in fluctuating conditions and how these microcosms can yield insights into microscale microbial activities.
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Affiliation(s)
- Kriti Sharma
- Department of Biology, University of North CarolinaChapel HillUnited States
| | - Márton Palatinszky
- Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of ViennaViennaAustria
| | - Georgi Nikolov
- Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of ViennaViennaAustria
| | - David Berry
- Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of ViennaViennaAustria
| | - Elizabeth A Shank
- Department of Biology, University of North CarolinaChapel HillUnited States
- Department of Microbiology and Immunology, University of North CarolinaChapel HillUnited States
- Program in Systems Biology, University of Massachusetts Medical SchoolWorcesterUnited States
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Charlier Q, Lortie F, Gerard J. How does paraffin wax prevent evaporation of acrylic‐based syrups dedicated to fiber‐reinforced composite processing? J Appl Polym Sci 2020. [DOI: 10.1002/app.48685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Quentin Charlier
- Univ‐Lyon, INSA‐Lyon, Ingénierie des Matériaux Polymères, UMR CNRS 5223 Villeurbanne France
| | - Frédéric Lortie
- Univ‐Lyon, INSA‐Lyon, Ingénierie des Matériaux Polymères, UMR CNRS 5223 Villeurbanne France
| | - Jean‐François Gerard
- Univ‐Lyon, INSA‐Lyon, Ingénierie des Matériaux Polymères, UMR CNRS 5223 Villeurbanne France
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Kim YT, Min H, Strano MS, Han JH, Lee CY. Hygroscopic Micro/Nanolenses along Carbon Nanotube Ion Channels. NANO LETTERS 2020; 20:812-819. [PMID: 31670525 DOI: 10.1021/acs.nanolett.9b01767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Nanolenses of alkali metal halides can be a unique optical element due to their hygroscopicity, optical transparency, and high mobility of constituent ions. It has been challenging, however, to form and place such lenses in a controlled manner. Here, we report micro/nanolenses of various alkali metal halides arranged as a one-dimensional (1D) array, using the exterior of single-walled carbon nanotubes (SWNTs) as a template for forming the lenses. Applying an electrical bias to an aqueous solution of alkali metal halides placed at the end of an SWNT array causes ionic transport along the exterior of SWNTs and the subsequent formation of salt micro/nanocrystals. The crystals serve as micro/nanolenses that optically visualize individual SWNTs and amplify their Raman scattering by orders of magnitude. Molecules dissolved in the ionic solution can be electrokinetically transported along the nanotubes, captured within the lenses, and analyzed by Raman spectroscopy, which we demonstrate by detecting ∼12 attomoles of glucose and 2 femtomoles of urea. The hygroscopic salt nanolenses are robust under various ambient conditions indefinitely, by transitioning to liquid droplets above their deliquescence relative humidity, yet can be removed nondestructively by water. Our approach could have broad implications in the optical visualization of 1D nanostructures, molecular transport or chemical reactions in 1D space, and molecular spectroscopy in salty environments.
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Affiliation(s)
| | | | - Michael S Strano
- Department of Chemical Engineering , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Jae-Hee Han
- Department of Materials Science and Engineering , Gachon University , Seongnam 13120 , Republic of Korea
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Oelkrug D, Boldrini B, Rebner K. Comparative Raman study of transparent and turbid materials: models and experiments in the remote sensing mode. Anal Bioanal Chem 2016; 409:673-681. [DOI: 10.1007/s00216-016-9582-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 04/11/2016] [Accepted: 04/19/2016] [Indexed: 11/30/2022]
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