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Maafi M. On photokinetics under polychromatic light. Front Chem 2024; 12:1367276. [PMID: 38711947 PMCID: PMC11070525 DOI: 10.3389/fchem.2024.1367276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 03/12/2024] [Indexed: 05/08/2024] Open
Abstract
Since the dawn of photochemistry 150 years ago, photoreactions have been conducted under polychromatic light. However, despite the pivotal role that photokinetics should naturally play for such reactive photosystems, the literature lacks a comprehensive description of that area. Indeed, one fails to identify explicit model integrated rate laws for these reactions, a characteristic type for their kinetic behavior, or their kinetic order. In addition, there is no consensus in the community on standardized investigative tools to evaluate the reactivity of these photosystems, nor are there venues for the discussion of such photokinetic issues. The present work is a contribution addressing some of these knowledge gaps. It proposes an unprecedented general formula capable of mapping out the kinetic traces of photoreactions under polychromatic light irradiation. This article quantitatively discusses several reaction situations, including the effects of initial reactant concentration and the presence of spectator molecules. It also develops a methodology for standardizing actinometers and defines and describes both the spectral range of highest reactivity and the photonic yield. The validity of the model equation has been proven by comparing its results to both theoretical counterparts and those generated by fourth-order Runge-Kutta numerical calculations. For the first time, a confirmation of the Φ -order character of the kinetics under polychromatic light was established.
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Affiliation(s)
- Mounir Maafi
- Leicester School of Pharmacy, De Montfort University, Leicester, United Kingdom
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Maafi M. On photokinetics under monochromatic light. Front Chem 2023; 11:1233151. [PMID: 37780986 PMCID: PMC10538970 DOI: 10.3389/fchem.2023.1233151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 08/22/2023] [Indexed: 10/03/2023] Open
Abstract
The properties of photokinetics under monochromatic light have not yet been fully described in the literature. In addition, for the last 120 years or so, explicit, handy model equations that can map out the kinetic behaviour of photoreactions have been lacking. These gaps in the knowledge are addressed in the present paper. Several general features of such photokinetics were investigated, including the effects of initial reactant concentration, the presence of spectator molecules, and radiation intensity. A unique equation, standing for a pseudo-integrated rate law, capable of outlining the kinetic behaviour of any photoreaction is proposed. In addition, a method that solves for quantum yields and absorption coefficients of all species of a given photoreaction is detailed. A metric (the initial velocity) has been adopted, and its reliability for the quantification of several effects was proven by theoretical derivation, Runge-Kutta numerical integration calculations and through the model equation proposed. Overall, this study shows that, under monochromatic light, photoreaction kinetics is well described by Φ -order kinetics, which is embodied by a unifying model equation. This paper is aimed at contributing to rationalising photokinetics via reliable, easy-to-use mathematical tools.
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Affiliation(s)
- Mounir Maafi
- Leicester School of Pharmacy, De Montfort University, Leicester, United Kingdom
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Hayat Z, Bchellaoui N, Deo C, Métivier R, Bogliotti N, Xie J, Buckle M, El Abed AI. Fast Active Merging of Microdroplets in Microfluidic Chambers Driven by Photo-Isomerisation of Azobenzene Based Surfactants. Biosensors (Basel) 2019; 9:bios9040129. [PMID: 31683751 PMCID: PMC6956313 DOI: 10.3390/bios9040129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 10/25/2019] [Accepted: 10/28/2019] [Indexed: 11/16/2022]
Abstract
In this work, we report on the development of a newly synthesized photoactive reversible azobenzene derived surfactant polymer, which enables active and fast control of the merging of microdroplets in microfluidic chambers, driven by a pulsed UV laser optical stimulus and the well known cis-trans photo-isomerisation of azobenzene groups. We show for the first time that merging of microdroplets can be achieved optically based on a photo-isomerization process with a high spatio-temporal resolution. Our results show that the physical process lying behind the merging of microdroplets is not driven by a change in surface activity of the droplet stabilizing surfactant under UV illumination (as originally expected), and they suggest an original mechanism for the merging of droplets based on the well-known opto-mechanical motion of azobenzene molecules triggered by light irradiation.
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Affiliation(s)
- Zain Hayat
- Laboratoire de Photonique Quantique et Moléculaire (LPQM), UMR 8537, Ecole Normale Supérieure Paris Saclay, CentraleSupélec, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan, France.
| | - Nizar Bchellaoui
- Laboratoire de Photonique Quantique et Moléculaire (LPQM), UMR 8537, Ecole Normale Supérieure Paris Saclay, CentraleSupélec, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan, France.
| | - Claire Deo
- Photophysique et Photochimie Supramoléculaires et Macromoléculaires (PPSM), UMR 8531, Ecole Normale Supérieure Paris Saclay, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan, France.
| | - Rémi Métivier
- Photophysique et Photochimie Supramoléculaires et Macromoléculaires (PPSM), UMR 8531, Ecole Normale Supérieure Paris Saclay, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan, France.
| | - Nicolas Bogliotti
- Photophysique et Photochimie Supramoléculaires et Macromoléculaires (PPSM), UMR 8531, Ecole Normale Supérieure Paris Saclay, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan, France.
| | - Juan Xie
- Photophysique et Photochimie Supramoléculaires et Macromoléculaires (PPSM), UMR 8531, Ecole Normale Supérieure Paris Saclay, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan, France.
| | - Malcolm Buckle
- Laboratoire de Biologie et Pharmacologie AppliquéE (LBPA), UMR 8113, Ecole Normale Supérieure Paris Saclay, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan, France.
| | - Abdel I El Abed
- Laboratoire de Photonique Quantique et Moléculaire (LPQM), UMR 8537, Ecole Normale Supérieure Paris Saclay, CentraleSupélec, CNRS, Université Paris-Saclay, 61 avenue du Président Wilson, 94235 Cachan, France.
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