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Patel D, Vaswani P, Ray D, Bhatia D, Aswal VK, Kuperkar K, Bahadur P. Additive-anchored thermoresponsive nanoscale self-assembly generation in normal and reverse Tetronics®. Phys Chem Chem Phys 2024; 26:6372-6385. [PMID: 38315058 DOI: 10.1039/d3cp06329a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Self-assembly of ethylene oxide (EO)-propylene oxide (PO)-based star-shaped block copolymers (BCPs) in the presence of different kinds of additives is investigated in an aqueous solution environment. Commercially available four-armed BCPs, namely Tetronics® (normal: T904 with EO as the terminal end block; and reverse: T90R4 with PO as the terminal end block), each with 40%EO, are used. The effect of various additives such as electrolytes (NaCl and Na2SO4), nonelectrolyte polyols (glucose and sorbitol), and ionic surfactants (viz. anionic-sodium dodecyl sulfate (SDS), cationic-dodecyltrimethylammonium bromide (DTAB) and zwitterionic dodecyldimethylammonium propane sulfonate (C12PS)) on these BCPs is examined to observe their influence on micellization behaviour. The presence of salts and polyols displayed interesting phase behaviour, i.e., the cloud point (CP) was decreased, the water structure was affected and the micelles were dehydrated by expelling water molecules, and thus they were likely to promote micelle formation/growth. In contrast, ionic surfactants in small amounts interacted with the BCPs and showed an increase in CPs thereby forming mixed micelles with increasing charges and decreasing micellar sizes, finally transforming to small surfactant-rich mixed micelles. Molecular interactions such as electrostatic and hydrogen bonding involved within the examined entities are put forth employing a computational simulation approach using the Gaussian 09 window for calculation along with the GaussView 5.0.9 programming software using the (DFT)/B3LYP method and 3-21G basis set. The hydrodynamic diameter (Dh) of the micelles is examined using dynamic light scattering (DLS), while the various micellar parameters inferring the shape/geometry are obtained using small-angle neutron scattering (SANS) by the best fitting of the structure factors. It is observed that 10 w/v% T904 remains as spherical micelles with some micellar growth under physiological conditions (37 °C), while 10 w/v% T90R4 remains as unimers and forms spherical micelles in the presence of additives at 37 °C. Furthermore, the additive-induced micellar systems are tested as developing nanovehicles for anticancer (curcumin, Cur) drug solubilization using UV-vis spectroscopy, which shows a prominent increase in absorbance with enhanced solubilization capacity. Additionally, the cytotoxic effect of Cur loaded on the BCP micelles in HeLa cells is studied through confocal microscopy by capturing fluorescence images that depict HeLa cell growth inhibition under the influence of additive-induced micellar systems.
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Affiliation(s)
- Dhruvi Patel
- Department of Chemistry, Sardar Vallabhbhai National Institute of Technology (SVNIT), Ichchhanath, Surat-395 007, Gujarat, India.
- School of Civil and Environmental Engineering, Cornell University, Ithaca, 14850, NY, USA
| | - Payal Vaswani
- Biomedical Engineering, Indian Institute of Technology Gandhinagar (IITGn), Gandhinagar-382 355, Palaj, Gujarat, India
| | - Debes Ray
- Solid State Physics Division, Bhabha Atomic Research Centre (BARC), Trombay, Mumbai-400 085, Maharashtra, India
- Biomacromolecular Systems and Processes, Institute of Biological Information Processing, Forschungszentrum Julich, 52428, Germany
| | - Dhiraj Bhatia
- Biomedical Engineering, Indian Institute of Technology Gandhinagar (IITGn), Gandhinagar-382 355, Palaj, Gujarat, India
| | - Vinod K Aswal
- Solid State Physics Division, Bhabha Atomic Research Centre (BARC), Trombay, Mumbai-400 085, Maharashtra, India
| | - Ketan Kuperkar
- Department of Chemistry, Sardar Vallabhbhai National Institute of Technology (SVNIT), Ichchhanath, Surat-395 007, Gujarat, India.
| | - Pratap Bahadur
- Department of Chemistry, Veer Narmad South Gujarat University (VNSGU), Surat-395 007, Gujarat, India
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Anilkumar A, Dutta Choudhury S. Self-assembly of Reverse Poloxamine Induced by Saccharide Excipients: Insights from Fluorescence. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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Bhattacharjee S, Pandit S, Bahadur P, Seth D. Photophysical Studies of a Hydrophilic Molecule in Normal and Reverse Tetronics® Solutions. J Photochem Photobiol A Chem 2023. [DOI: 10.1016/j.jphotochem.2023.114660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
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Effect of hydrophobic modification of block copolymers on the self-assembly, drug encapsulation and release behavior. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Chakrabarti C, Khan Pathan S, Deep Punetha V, Pillai SA. Interaction of Tetronics® micelles with stimuli and additives and a commanding aspect towards drug delivery: An overview. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Patel D, Ray D, Aswal VK, Kuperkar K, Bahadur P. Micellar assembly leading to structural growth/transition in normal and reverse Tetronics® in single and mixed solution environment. SOFT MATTER 2022; 18:4543-4553. [PMID: 35674288 DOI: 10.1039/d2sm00321j] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This study scrutinizes the self-association of ethylene oxide (EO)-propylene oxide (PO)-based star-shaped block copolymers as normal Tetronic® (T904) and reverse Tetronic® R (T90R4) with varying molecular characteristics and different hydrophilic-hydrophobic ratios in an aqueous solution environment. These thermo-responsive solutions appear clear, transparent or bluish up to 10%w/v, which anticipated the probable transition of unimers to spherical or ellipsoidal micelles which is complemented by scattering experiments. In a single-solution environment, 10%w/v T904 formed star-shaped micelles at ambient temperature and exhibited a micellar growth/transition with temperature ageing. While 10%w/v T90R4 exists as unimers or a Gaussian coil over a wide range of temperature. Very interestingly, close to the cloud point (CP) flower-shaped spherical and ellipsoidal micelles were formed. A similar proposed micellar scheme was also examined for mixed systems T904 : T90R4 in varying ratios (1 : 0, 3 : 1, 1 : 1, 1 : 3 and 0 : 1) giving an account to the solution behavior of the mixtures. An amalgamation of dynamic light scattering (DLS) and small-angle neutron scattering (SANS) techniques achieved the thorough extraction of the structural parameters of the micellar system. The hydrodynamic diameter (Dh) of the micelles with temperature variation was evaluated from dynamic light scattering (DLS) while the structure factor of the micelles was found by employing small-angle neutron scattering (SANS). Furthermore, the single and mixed micellar systems were quantitatively and qualitatively examined for anticancer drug solubilization using UV-vis spectroscopy for their superior use as potential nanocargos.
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Affiliation(s)
- Dhruvi Patel
- Department of Chemistry, Sardar Vallabhbhai National Institute of Technology (SVNIT), Ichchhanath, Surat-395 007, Gujarat, India.
| | - Debes Ray
- Solid State Physics Division, Bhabha Atomic Research Centre (BARC), Trombay, Mumbai-400 085, Maharashtra, India
| | - Vinod K Aswal
- Solid State Physics Division, Bhabha Atomic Research Centre (BARC), Trombay, Mumbai-400 085, Maharashtra, India
| | - Ketan Kuperkar
- Department of Chemistry, Sardar Vallabhbhai National Institute of Technology (SVNIT), Ichchhanath, Surat-395 007, Gujarat, India.
| | - Pratap Bahadur
- Department of Chemistry, Veer Narmad South Gujarat University (VNSGU), Surat-395 007, Gujarat, India
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Chang D, Niu S, Chu H, Zang D, Sun J, Wang X, Liu T. Influence of amino acids on the aggregation behavior and drug solubilization of branched block copolymers. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lakshmi SN, Bahadur P, Choudhury SD. Fate of Photoinduced Electron Transfer Reactions with Temperature- and pH-Induced Assembly/Disassembly of Star Block Copolymer Micelles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:14125-14134. [PMID: 34797674 DOI: 10.1021/acs.langmuir.1c02383] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The assembly/disassembly of star block copolymers induced by changes in temperature or pH of the medium is anticipated to have interesting implications for hosting/releasing drugs and tuning chemical reactions. This study investigates the possibility of employing the dually sensitive self-assembly of an ethylene oxide-propylene oxide star block copolymer, Tetronic T904, to influence photoinduced electron transfer (ET) reactions, on switching from the assembled state (micelle) when temperature is above the critical micelle temperature (CMT) and pH of the medium is above the pKa of T904 to the dissociated (unimer) state when either the temperature is below the CMT or the polymer is protonated. Steady-state and time-resolved fluorescence techniques have been used to characterize the microenvironments of the reactants in T904 solutions under different temperature and pH conditions and to determine ET rate constants. Interestingly, the bimolecular ET rate constants in both assembled and disassembled states of T904 depict a bell-shaped correlation with the driving force of the reaction, in accordance with Marcus inversion behavior instead of the usual Rehm-Weller behavior seen in conventional solvents. The assembly/disassembly of T904 stimulated by temperature or pH affects the micropolarity in the reactant environment, the magnitude of ET rate constants, and the position of inversion on the exergonicity scale.
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Affiliation(s)
- Suresh Nayana Lakshmi
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Pratap Bahadur
- Department of Chemistry, Veer Narmad South Gujarat University, Surat 395007, India
| | - Sharmistha Dutta Choudhury
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, India
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Photoinduced electron transfer reactions in mixed micelles of a star block copolymer and surface active ionic liquids: Role of the anion. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Sarolia J, Shukla R, Ray D, Aswal VK, Choudhury SD, Bahadur P, Tiwari S. Mobility of doxorubicin in TPGS micelles in response to sodium taurodeoxycholate incorporation: Analyses based on scattering and fluorescence studies. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.126693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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11
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Ziolek RM, Smith P, Pink DL, Dreiss CA, Lorenz CD. Unsupervised Learning Unravels the Structure of Four-Arm and Linear Block Copolymer Micelles. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02523] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Robert M. Ziolek
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, U.K
| | - Paul Smith
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, U.K
| | - Demi L. Pink
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, U.K
| | - Cécile A. Dreiss
- Institute of Pharmaceutical Science, King’s College London, London SE1 9NH, U.K
| | - Christian D. Lorenz
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, U.K
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Ziolek RM, Omar J, Hu W, Porcar L, González-Gaitano G, Dreiss CA, Lorenz CD. Understanding the pH-Directed Self-Assembly of a Four-Arm Block Copolymer. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c01694] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Robert M. Ziolek
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, United Kingdom
| | - Jasmin Omar
- Institute of Pharmaceutical Science, King’s College London, London SE1 9NH, United Kingdom
| | - Wenjing Hu
- Institute of Pharmaceutical Science, King’s College London, London SE1 9NH, United Kingdom
| | - Lionel Porcar
- Institut Max Von Laue Paul Langevin, F-38042 Grenoble 9, France
| | | | - Cécile A. Dreiss
- Institute of Pharmaceutical Science, King’s College London, London SE1 9NH, United Kingdom
| | - Christian D. Lorenz
- Biological Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, United Kingdom
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Tandon L, Thakur P, Khullar P, Bakshi MS. Longitudinal surface plasmon resonance of gold nanoparticles as an indicator for interparticle fusions controlled by tetronics. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.114319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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14
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Samanta P, Dutta Choudhury S, Pal H. Lanthanide (III) ions as multichannel acceptors for bimolecular photoinduced electron transfer reactions with coumarin dyes. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Patel D, Ray D, Kuperkar K, Pal H, Aswal VK, Bahadur P. Solubilization, micellar transition and biocidal assay of loaded antioxidants in Tetronic® 1304 micelles. POLYM INT 2020. [DOI: 10.1002/pi.5962] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Dhruvi Patel
- Applied Chemistry Department Sardar Vallabhbhai National Institute of Technology (SVNIT) Surat India
| | - Debes Ray
- Solid State Physics Division Bhabha Atomic Research Centre Mumbai India
| | - Ketan Kuperkar
- Applied Chemistry Department Sardar Vallabhbhai National Institute of Technology (SVNIT) Surat India
| | - Haridas Pal
- Analytical Division Bhabha Atomic Research Centre Mumbai India
| | - Vinod K Aswal
- Solid State Physics Division Bhabha Atomic Research Centre Mumbai India
| | - Pratap Bahadur
- Department of Chemistry Veer Narmad South Gujarat University (VNSGU) Surat India
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Saladin M, Rumble CA, Wagle DV, Baker GA, Maroncelli M. Characterization of a New Electron Donor-Acceptor Dyad in Conventional Solvents and Ionic Liquids. J Phys Chem B 2019; 123:9395-9407. [PMID: 31596593 DOI: 10.1021/acs.jpcb.9b07077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Ionic liquids are being tested as potential replacements for current electrolytes in energy-related applications. Electron transfer (ET) plays a central role in these applications, making it essential to understand how ET in ionic liquids differs from ET in conventional organic solvents and how these differences affect reaction kinetics. A new intramolecular electron donor-acceptor probe was synthesized by covalently linking the popular photoacceptor coumarin 152 with the donor dimethylaniline to create the dyad "C152-DMA" for potential use in probing dynamical solvent effects in ionic liquids. Molecular dynamics simulations of this dyad show the considerable conformational flexibility of the linker group but over a range of geometries in which the ET rate parameters vary little and should have minimal effect on reaction times >100 ps. Steady-state and time-resolved fluorescence methods show the spectra of C152-DMA to be highly responsive to solvent polarity, with ET rates varying over the range of 108 to 1012 s-1 between nonpolar and high-polarity conventional solvents. The sensitivity to hydrolysis in the presence of acidic impurities limits the dyad's use to ionic liquids of high purity. The results in the few ionic liquids examined here suggest that in addition to solvent polarity, electron transfer in C152-DMA also depends on solvent fluidity or solvation times.
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Affiliation(s)
- Marissa Saladin
- Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Christopher A Rumble
- Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Durgesh V Wagle
- Department of Chemistry , University of Missouri - Columbia , Columbia , Missouri 65211 , United States
| | - Gary A Baker
- Department of Chemistry , University of Missouri - Columbia , Columbia , Missouri 65211 , United States
| | - Mark Maroncelli
- Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
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Darvin JR, Berg MA. Micelle Heterogeneity from the 2D Kinetics of Solute Rotation. J Phys Chem Lett 2019; 10:6885-6891. [PMID: 31618033 DOI: 10.1021/acs.jpclett.9b02783] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The chemical and physical properties of microstructured materials vary with position. The photophysics of solute molecules can measure these local properties, but they often show multiple rates (rate dispersion), which complicates the interpretation. In the case of micelles, rate dispersion in a solute's anisotropy decay has been assigned to either local anisotropy or heterogeneity in the local viscosity. To resolve this conflict, the rotation of PM597 molecules in SDS micelles has been measured by polarized MUPPETS (multiple population-period transient spectroscopy). This 2D technique shows that heterogeneity is strong and that local anisotropy is minimal. The results suggest that on a subnanosecond time scale, the solute sees only one strong fluctuation of the micelle structure. The anisotropic, average structure emerges on longer time scales.
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Affiliation(s)
- Jason R Darvin
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Mark A Berg
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
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Samanta P, Dutta Choudhury S, Pal H. Kinetics and Energetics of Ultrafast Bimolecular Photoinduced Electron Transfer Reactions in Pluronic-Surfactant Supramolecular Assemblies. J Phys Chem B 2019; 123:5942-5953. [PMID: 31246469 DOI: 10.1021/acs.jpcb.9b04223] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Understanding the kinetics and energetics of photoinduced electron transfer (PET) reactions in constrained media has attracted considerable research interest, as constrained media provide a handle to tune the microenvironments and consequently the mechanisms of PET reactions. In this study, PET reactions between excited 7-aminocoumarin acceptors and ground-state N,N-dimethylaniline (DMAN) donor have been investigated in mixed micellar media composed of triblock copolymer, P123, and anionic surfactant, sodium dodecyl sulfate (SDS), with varying SDS-to-P123 molar ratios (n values). The objective is to elucidate the role of the n values in the rates and energetics of PET reactions over the entire time range from the subpicosecond to the subnanosecond domain, especially in regard to the applicability of the two-dimensional ET (2DET) mechanism. It is observed that by changing the n values, there is a significant change in the hydration characteristics of the SDS-P123 mixed micelles, which in turn changes the kinetics to energetic correlations for the PET reactions. Fluorescence from the excited coumarin acceptors undergoes substantial quenching due to PET from DMAN donor in all of the studied micelles as evidenced from steady-state, subnanosecond time-resolved (TR) and ultrafast (subpicosecond/femtosecond) fluorescence up-conversion measurements. The quenching rate constants (kq), estimated from subnanosecond TR fluorescence studies, and the individual component-wise decay rates (τi-1), estimated from up-conversion measurements, increase gradually with increasing n value, corroborating well with the sequentially increased micropolarity of the mixed micelles. Interestingly, it is observed that the correlations of either kq (from subnanosecond studies) or τi-1 (from femtosecond studies) with the reaction exergonicity (-ΔG°) show the noteworthy Marcus inversion (MI) behavior in a very consistent and similar manner for the entire time window, from subpicoseconds to subnanoseconds. The onset of MI always appears at an exergonicity (-ΔG°MI) much lower than solvent reorganization energy (λs), suggesting the involvement of 2DET mechanism throughout the subpicosecond to subnanosecond time domains. The present results thus provide a comprehensive picture of the kinetics and energetics of the PET reactions in constrained media for the whole time span and unequivocally establish the applicability of 2DET mechanism for the PET reactions in constrained media, eliminating any apprehensions about the effect of time resolution of the subnanosecond setup on the observed Marcus inversion behavior. This is indeed an important finding, providing valuable insights for PET reactions in constrained media, which has not been explored explicitly in any of the previous studies. Observation of MI behavior and the modulations in the PET reactions by simply changing the composition of SDS in the SDS-P123 mixed micelles are noteworthy findings of the present study and are expected to find suitable applications for better utilization and outcome of the PET reactions.
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Affiliation(s)
- Papu Samanta
- Homi Bhabha National Institute , Training School Complex , Anushaktinagar, Mumbai 400094 , India
| | | | - Haridas Pal
- Homi Bhabha National Institute , Training School Complex , Anushaktinagar, Mumbai 400094 , India
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Gharat PM, Pal H, Dutta Choudhury S. Photophysics and luminescence quenching of carbon dots derived from lemon juice and glycerol. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 209:14-21. [PMID: 30343105 DOI: 10.1016/j.saa.2018.10.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 10/08/2018] [Accepted: 10/14/2018] [Indexed: 06/08/2023]
Abstract
During the past decade, carbon dots have emerged as a fascinating class of luminescent nanomaterials with versatile application potentials in bioimaging, labeling, photocatalysis and optoelectronics. Currently, intensive research is concentrated on understanding the intriguing optical properties of these promising materials and their utility as luminescence sensors. In this article, we describe the photoluminescence of carbon dots obtained from a bioresource (lemon juice) and from a small molecule precursor (glycerol), especially the quenching of their emission by nitrobenzene and Hg2+ ions, as representative cases. Stern-Volmer analysis using steady-state and time-resolved emission measurements, suggests the involvement of both transient quenching and dynamic quenching mechanisms in the interaction of the carbon dots with nitrobenzene. The radius of the quenching sphere is estimated to be slightly greater than the contact distances between the respective carbon dots and nitrobenzene, which is in reasonable agreement with the "sphere of action" model for transient quenching. In the interaction with Hg2+ ions, electrostatic attraction plays a major role, and the quenching mechanism involves predominantly static and dynamic quenching. The static quenching constant matches well with the binding constant of the carbon dots with the metal ion.
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Affiliation(s)
- Poojan Milan Gharat
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Haridas Pal
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India; Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, India
| | - Sharmistha Dutta Choudhury
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India; Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, India.
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Samanta P, Halder P, Bahadur P, Dutta Choudhury S, Pal H. Effect of Ionic Liquids as Cosurfactants on Photoinduced Electron Transfer in Tetronic Micelles. J Phys Chem B 2018; 122:10190-10201. [PMID: 30351120 DOI: 10.1021/acs.jpcb.8b08766] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study investigates the role of varying alkyl chain lengths of a series of surface-active 1-alkyl-3-methylimidazolium tetrafluoroborate ([C nMIm][BF4], n = 4, 6, and 10) ionic liquids (ILs) as cosurfactants in modifying the micellar characteristics of a tetronic star-block copolymer, T1304, and the consequent effects on bimolecular photoinduced electron transfer (PET) reactions carried out in these T1304-IL mixed micellar systems. Using coumarin 153 as the probe dye and following ground-state absorption, steady-state fluorescence, and time-resolved emission measurements, the micropolarity, microviscosity, and solvent relaxation dynamics in the micellar palisade layer have been revealed both in pure T1304 and in T1304-IL systems. With increasing alkyl chain length of the ILs, the palisade layer of the micelles gradually becomes more polar and less viscous, suggesting better incorporation of the longer alkyl chain length ILs as cosurfactants into the T1304 micelles. The bimolecular PET reactions, involving 7-aminocoumarins as acceptors and N, N-dimethylaniline as the donor, are considerably modulated in T1304 micelles by the presence of the ILs, the effect being more prominent for ILs with longer alkyl chain lengths. In all of the micellar systems, correlations of the electron transfer (ET) kinetics with the reaction exergonicity (-Δ G0) show clear Marcus inversion (MI) behavior where onsets of MI invariably appear at significantly lower exergonicities, suggesting the involvement of a two-dimensional ET mechanism. Interestingly, the Marcus correlations display significant variations, namely, enhanced reaction rates and gradual shift in the onset of MI toward higher exergonicity, as longer alkyl chain length ILs are sequentially introduced as cosurfactants. From the observed results, it is convincingly realized that 1-alkyl-3-methylimidazolium-based ILs can be used satisfactorily as cosurfactants in tetronic star-block copolymer solutions to modulate PET reactions very significantly for their better utilizations in suitable applied areas.
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Affiliation(s)
- Papu Samanta
- Homi Bhabha National Institute , Training School Complex , Anushaktinagar, Mumbai 400094 , India
| | | | - Pratap Bahadur
- Department of Chemistry , Veer Narmad South Gujarat University , Surat 395007 , India
| | | | - Haridas Pal
- Homi Bhabha National Institute , Training School Complex , Anushaktinagar, Mumbai 400094 , India
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