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Sarker P, Su X, Rojas OJ, Khan SA. Colloidal interactions between nanochitin and surfactants: Connecting micro- and macroscopic properties by isothermal titration calorimetry and rheology. Carbohydr Polym 2024; 341:122341. [PMID: 38876727 DOI: 10.1016/j.carbpol.2024.122341] [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: 04/18/2024] [Revised: 05/22/2024] [Accepted: 05/27/2024] [Indexed: 06/16/2024]
Abstract
This study elucidates the intricate interactions between chitin nanocrystals (ChNC) and surfactants of same hydrophobic tail (C12) but different head groups types (anionic, cationic, nonionic): sodium dodecyl sulfate (SDS), dodecyltrimethylammonium bromide (DTAB), and polyoxyethylene(23)lauryl ether (Brij-35). Isothermal Titration Calorimetry (ITC) and rheology are used to study the complex ChNC-surfactant interactions in aqueous media, affected by adsorption, self-assembly and micellization. The ITC results demonstrate that the surfactant head group significantly influences the dynamics and nature of the involved phenomena. Cationic DTAB's reveal minimal interaction with ChNC, non-ionic Brij-25's interact moderately at low concentrations driven by hydrophobic effects while SDS's interacts strongly and show complex interaction patterns that fall across four distinct regimes with SDS addition. We attribute such behavior to initiate through electrostatic attraction and terminate in surfactant micelle formation on ChNC surfaces. ITC also elucidates the impact of ChNC concentration on key parameters including critical aggregation concentration (CAC) and saturation concentration (C2). Dynamic rheological analysis indicates the molecular interactions translate to non-linear variations in the elastic modulus (G') upon SDS addition mirroring that observed in ITC experiments. Such a direct correlation between molecular interactions and macroscopic rheological properties provides insights to aid in the creation of nanocomposites with tailored properties.
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Affiliation(s)
- Prottasha Sarker
- Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, United States
| | - Xiaoya Su
- Bioproducts Institute, Department of Chemical & Biological Engineering, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Orlando J Rojas
- Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, United States; Bioproducts Institute, Department of Chemical & Biological Engineering, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada; Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada; Department of Wood Science, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
| | - Saad A Khan
- Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, United States.
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Jozanović M, Sakač N, Karnaš M, Medvidović-Kosanović M. Potentiometric Sensors for the Determination of Anionic Surfactants - A Review. Crit Rev Anal Chem 2019; 51:115-137. [PMID: 31690085 DOI: 10.1080/10408347.2019.1684236] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Anionic surfactants are important components of many products used in everyday life in all households. They are also applied in various industrial fields at a very large scale. Since they have a negative influence on the environment, it is an imperative to monitor their concentration in aquatic ecosystems. Therefore, it is of great importance to develop new methods for the determination of a wide spectra of anionic surfactants in complex environmental samples in a short time. A comprehensive review of potentiometric sensors for the determination of anionic surfactants in the last 50 years is given with special concern to papers published since 2000, but noting some earlier published important papers. The latest development in use of new ionophores, polymer formulations, and nanomaterials is presented. Additionally, the application of new potentiometric sensors in batch mode or in miniaturized microfluidic methods is discussed.
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Affiliation(s)
- Marija Jozanović
- Department of Chemistry, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Nikola Sakač
- Faculty of Geotechnical Engineering, University of Zagreb, Varaždin, Croatia
| | - Maja Karnaš
- Faculty of Agrobiotechnical Sciences Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
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Ibrahim MS, Valencony J, King S, Murray M, Szczygiel A, Alexander BD, Griffiths PC. Studying the interaction of hydrophobically modified ethoxylated urethane (HEUR) polymers with sodium dodecylsulfate (SDS) in concentrated polymer solutions. J Colloid Interface Sci 2018; 529:588-598. [DOI: 10.1016/j.jcis.2018.06.042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 06/17/2018] [Accepted: 06/19/2018] [Indexed: 11/25/2022]
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Zhang H, Li D, Pei L, Zhang L, Wang F. The Stability of the Micelle Formed by Chain Branch Surfactants and Polymer Under Salt and Shear Force: Insight from Dissipative Particle Dynamics Simulation. J DISPER SCI TECHNOL 2016. [DOI: 10.1080/01932691.2015.1042584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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5
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Chen S, Duhamel J, Peng B, Zaman M, Tam KC. Interactions between a series of pyrene end-labeled poly(ethylene oxide)s and sodium dodecyl sulfate in aqueous solution probed by fluorescence. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:13164-13175. [PMID: 25291259 DOI: 10.1021/la502912z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The interactions between a series of poly(ethylene oxide)s covalently labeled at both ends with pyrene pendants (PEO(X)-Py2, where X represents the number-average molecular weight of the PEO chains and equals 2K, 5K, 10K, and 16.5K) and an ionic surfactant, namely, sodium dodecyl sulfate (SDS), in water were investigated at a fixed pyrene concentration of 2.5 μM corresponding to polymer concentrations smaller than 21 mg/L and with an SDS concentration range between 5 × 10(-6) and 0.02 M, thus encompassing the 8 mM critical micelle concentration (CMC) of SDS in water. The steady-state fluorescence spectra showed that the I1/I3 ratio decreased from 1.73 ± 0.06 for SDS concentration smaller than 2 mM where pyrene was exposed to water to 1.43 ± 0.03 for SDS concentration greater than 6 mM where pyrene was incorporated inside SDS micelles. The ratio of excimer-to-monomer emission intensities (the IE/IM ratio) of all PEO(X)-Py2 samples remained constant at low SDS concentrations, then increased, passed through a maximum at the same SDS concentration of 4 mM before decreasing to a plateau value that is close to zero for PEO(10K)-Py2 and PEO(16.5K)-Py2 but nonzero for PEO(2K)-Py2 and PEO(5K)-Py2. The pyrene end groups of these two latter samples could not bridge two different micelles due to the short PEO chain, and excimer was formed by intramolecular diffusion inside the same SDS micelle. Time-resolved fluorescence decays of the pyrene monomer and excimer of the PEO(X)-Py2 samples were acquired at various SDS concentrations and globally fitted according to the "Model Free" analysis over the entire range of SDS concentration. The molar fractions of various excited pyrene species and the rate constant of pyrene excimer formation retrieved from the analysis of fluorescence decays were obtained as a function of SDS concentration. Interactions between SDS and PEO could not be detected by isothermal titration calorimetry, potentiometry with a surfactant selective electrode, and conductance measurements.
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Affiliation(s)
- Shaohua Chen
- Institute for Polymer Research, Waterloo Institute for Nanotechnology, †Department of Chemistry and ‡Department of Chemical Engineering, University of Waterloo , Waterloo, ON N2L 3G1, Canada
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6
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Zhang ZX, Ni X, Li J. Cationic brush-like terpolymer with pH responsive thickening behavior in a surfactant system. POLYM INT 2014. [DOI: 10.1002/pi.4715] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Zhong-Xing Zhang
- Institute of Materials Research and Engineering; A*STAR (Agency for Science, Technology and Research); 3 Research Link Singapore 117602
| | - Xiping Ni
- Institute of Materials Research and Engineering; A*STAR (Agency for Science, Technology and Research); 3 Research Link Singapore 117602
| | - Jun Li
- Institute of Materials Research and Engineering; A*STAR (Agency for Science, Technology and Research); 3 Research Link Singapore 117602
- Department of Biomedical Engineering, Faculty of Engineering; National University of Singapore; 7 Engineering Drive 1 Singapore 117574
- NUS Graduate School for Integrative Sciences and Engineering (NGS); National University of Singapore; 28 Medical Drive Singapore 117456
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Peng B, Han X, Liu H, Tam KC. Binding of cationic surfactants to a thermo-sensitive copolymer below and above its cloud point. J Colloid Interface Sci 2013; 412:17-23. [DOI: 10.1016/j.jcis.2013.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 08/29/2013] [Accepted: 09/03/2013] [Indexed: 12/14/2022]
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8
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Electromotive force study on interaction between a triblock copolymer and cationic surfactants in water. Colloid Polym Sci 2012. [DOI: 10.1007/s00396-012-2884-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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9
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Zhang X, Ge L, Guo R. Energetic and conformational changes upon complexation of gelatin with sodium dodecyl sulfate. J Colloid Interface Sci 2012; 380:113-20. [DOI: 10.1016/j.jcis.2012.05.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 05/03/2012] [Accepted: 05/06/2012] [Indexed: 10/28/2022]
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Rufier C, Collet A, Viguier M, Oberdisse J, Mora S. Influence of Surfactants on Hydrophobically End-Capped Poly(ethylene oxide) Self-Assembled Aggregates Studied by SANS. Macromolecules 2011. [DOI: 10.1021/ma201150g] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | - Julian Oberdisse
- Laboratoire Leon Brillouin, CEA Saclay, F-91191 Gif Sur Yvette, France
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Rufier C, Collet A, Viguier M, Oberdisse J, Mora S. SDS Interactions with Hydrophobically End-Capped Poly(ethylene oxide) Studied by 13C NMR and SANS. Macromolecules 2009. [DOI: 10.1021/ma900361p] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
| | | | | | - Julian Oberdisse
- CEA Saclay, Laboratoire Leon Brillouin, F-91191 Gif Sur Yvette, France
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12
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Rufier C, Collet A, Viguier M, Oberdisse J, Mora S. Asymmetric End-Capped Poly(ethylene oxide). Synthesis and Rheological Behavior in Aqueous Solution. Macromolecules 2008. [DOI: 10.1021/ma800623d] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chantal Rufier
- Institut Charles Gerhardt, UMR-CNRS 5253, and Laboratoire des Colloïdes, Verres et Nanomatériaux, UMR-CNRS 5587, Université Montpellier 2, C.C 1702, Pl. E. Bataillon, F-34095 Montpellier Cedex 05, France
| | - André Collet
- Institut Charles Gerhardt, UMR-CNRS 5253, and Laboratoire des Colloïdes, Verres et Nanomatériaux, UMR-CNRS 5587, Université Montpellier 2, C.C 1702, Pl. E. Bataillon, F-34095 Montpellier Cedex 05, France
| | - Michel Viguier
- Institut Charles Gerhardt, UMR-CNRS 5253, and Laboratoire des Colloïdes, Verres et Nanomatériaux, UMR-CNRS 5587, Université Montpellier 2, C.C 1702, Pl. E. Bataillon, F-34095 Montpellier Cedex 05, France
| | - Julian Oberdisse
- Institut Charles Gerhardt, UMR-CNRS 5253, and Laboratoire des Colloïdes, Verres et Nanomatériaux, UMR-CNRS 5587, Université Montpellier 2, C.C 1702, Pl. E. Bataillon, F-34095 Montpellier Cedex 05, France
| | - Serge Mora
- Institut Charles Gerhardt, UMR-CNRS 5253, and Laboratoire des Colloïdes, Verres et Nanomatériaux, UMR-CNRS 5587, Université Montpellier 2, C.C 1702, Pl. E. Bataillon, F-34095 Montpellier Cedex 05, France
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13
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Boeris V, Farruggia B, Nerli B, Romanini D, Picó G. Protein-flexible chain polymer interactions to explain protein partition in aqueous two-phase systems and the protein–polyelectrolyte complex formation. Int J Biol Macromol 2007; 41:286-94. [PMID: 17449091 DOI: 10.1016/j.ijbiomac.2007.03.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2006] [Revised: 02/20/2007] [Accepted: 03/20/2007] [Indexed: 11/20/2022]
Abstract
Complexes formation between two model proteins (catalase and chymotrypsin) and polyelectrolytes (polyvinyl sulphonate and polyacrilic acid) and a non-charged flexible chain polymer (PCF) as polyethylene propylene oxide (molecular mass 8400) was studied by a spectroscopy technique combination: UV absorption, fluorescence emission and circular dichroism. All the polymers increase the protein surface hydrophobicity (S(0)) parameter value as a proof of the modification of the protein surface exposed to the solvent. Chymotrypsin showed an increase in its biological activity in polymer presence, which suggests a change in the superficial microenvironment. The decrease in the biological activity of catalase might be due to a competition between the polymer and the substrate. This result agrees with the polymer effect on the catalase superficial hydrophobic area. It was found that, when flexible chain polymers increase protein stability and the enzymatic activity they could be used to isolate this enzyme without inducing loss of protein enzymatic activity. Our findings suggest that the interactions are dependent on the protein physico-chemical parameters such as: isoelectric pH, hydrophobic surface area, etc.
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Affiliation(s)
- Valeria Boeris
- Bioseparation Lab, Physical-Chemistry Department, Faculty of Biochemical and Pharmaceutical Sciences, National University of Rosario, FonCyT, CIUNR and CONICET, Suipacha 570 (S2002RLK) Rosario, Argentina
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14
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Li L, Liu E, Lim CH. Micro-DSC and Rheological Studies of Interactions between Methylcellulose and Surfactants. J Phys Chem B 2007; 111:6410-6. [PMID: 17516676 DOI: 10.1021/jp0712957] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effects of a cationic surfactant, cetyltrimethylammonium bromide (CTAB), on the gelation of methylcellulose (MC) in aqueous solutions have been investigated by micro differential scanning calorimetry (micro DSC) and rheology. Methylcellulose had a weight average molecular weight of 310,000 and a degree of substitution of 1.8. The concentration of MC was kept at 0.5 wt % (0.016 mM) and 1 wt % (0.032 mM), and the concentration of CTAB in the MC solutions was varied from 0 to 0.6 wt % (16.5 mM). Upon heating, a single endothermic peak, which is due to the hydrophobic association and gelation of MC, shifts to lower temperatures with increasing CTAB for CTAB < or = CMC (0.93 mM or 0.034 wt %), and then it shifts to higher temperatures lineally with CTAB for CTAB > CMC. At the same time, the endothermic enthalpy decreases with increasing CTAB concentration. Even though CTAB shows a significant "salt-in" effect on the gelation of MC, it does not affect the pattern of the sol-gel transition as well as the gel strength of MC. At the highest concentration of CTAB, 0.60 wt %, MC is still able to form a gel. At a given ratio of CTAB/MC, the effect of CTAB on MC becomes stronger when the MC concentration is lower. The results for the MC-CTAB system are compared with an ionic surfactant, SDS and the significant differences in affecting the gelation of MC between two surfactants are recognized.
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Affiliation(s)
- Lin Li
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore.
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Liao D, Dai S, Tam KC. Rheological Properties of a Telechelic Associative Polymer in the Presence of α- and Methylated β-Cyclodextrins. J Phys Chem B 2006; 111:371-8. [PMID: 17214488 DOI: 10.1021/jp066490k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The viscosity of hydrophobic ethoxylated urethane (HEUR) solution decreased in the presence of alpha-CD or m-beta-CD; however their interactions were quite different. When the alpha-CD/hydrophobe molar ratio exceeded 5.0, the viscosity was close to that of a PEO solution of similar molecular weight. Oscillatory shear indicated that the mechanically active chains in HEUR solution decreased with the addition of alpha-CD. This agreed with the hypothesis that alpha-CD formed an inclusion complex with the hydrophobic moiety of the HEUR polymer, thereby destroying the transient hydrophobic associative network. The viscosity/temperature relationship of the alpha-CD/HEUR system (for HEUR with 70% of the PEO chains capped at both ends) did not obey the Arrhenius relationship for alpha-CD/hydrophobe molar ratio in the range 0.8-5.0. The low shear viscosity increased with increasing temperature at molar ratio of 1.0, and this was attributed to the competitive complexation of the alpha-CD/hydrophobe and the alpha-CD/PEO chain. Increasing temperature favored alpha-CD/PEO complexation. Comparison between the behavior of alpha-CD/HEUR and m-beta-CD/HEUR resulting from the different binding characteristics was discussed.
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Affiliation(s)
- Dongsheng Liao
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
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16
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Isothermal titration calorimetric studies on the interaction between sodium dodecyl sulfate and polyethylene glycols of different molecular weights and chain architectures. Colloids Surf A Physicochem Eng Asp 2006. [DOI: 10.1016/j.colsurfa.2006.04.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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17
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Tam KC, Wyn-Jones E. Insights on polymer surfactant complex structures during the binding of surfactants to polymers as measured by equilibrium and structural techniques. Chem Soc Rev 2006; 35:693-709. [PMID: 16862270 DOI: 10.1039/b415140m] [Citation(s) in RCA: 178] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
This tutorial review provides new insights into the binding interactions between anionic surfactant molecules and various macromolecules in solution. The systems are of inherent scientific interest because synergistic mixing between these two components leads to complexes commonly found in applications such as detergency, cosmetic products, rheology control, paint and pharmaceutical formulations. We describe how the basic foundations, which are prerequisite to characterize a given polymer/surfactant system are evaluated together with information on the binding mechanism and structure derived from several methodologies.
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Affiliation(s)
- Kam C Tam
- School of Mechanical & Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
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18
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Haldar B, Chakrabarty A, Mallick A, Mandal MC, Das P, Chattopadhyay N. Fluorometric and isothermal titration calorimetric studies on binding interaction of a telechelic polymer with sodium alkyl sulfates of varying chain length. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:3514-20. [PMID: 16584222 DOI: 10.1021/la053370f] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Steady-state fluorescence measurements and isothermal titration calorimetric experiments have been performed to study the interaction between a telechelic polymer, pyrene-end-capped poly(ethylene oxide) (PYPY), and sodium alkyl sulfate surfactants having decyl, dodecyl, and tetradecyl hydrocarbon tails. Fluorometric results suggest polymer-surfactant interaction in the very low range of polymer concentrations. The relative variation in the excimer to monomer pyrene emission intensities with varying surfactant concentration reveals that initial addition of surfactant favors intramolecular preassociation until the surfactant molecules start binding with the ethylene oxide (EO) chain. With the growing number of surfactant aggregates along the EO chain, the association becomes hindered due to the polyelectrolyte effect. The results from microcalorimetric titrations in the low concentration range of PYPY solution (approximately 10(-6) M) with alkyl sulfates suggest two kinds of surfactant-polymer interactions, one with the polymer hydrophobic end groups and the other with the ethylene oxide backbone. The overall polymer-surfactant interaction starts at a much lower surfactant concentration for the hydrophobically modified polymers compared to that in the case of unsubstituted poly(ethylene oxide) homopolymer. From the experiments critical aggregation concentration values and the second critical concentration where free micelles start forming have been determined. An endeavor has been made to unveil the mechanism underlying the corresponding associations of the surfactants with the polymer.
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Affiliation(s)
- Basudeb Haldar
- Department of Chemistry, Jadavpur University, Calcutta-700 032, India
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Wang Q, Li L, Liu E, Xu Y, Liu J. Effects of SDS on the sol–gel transition of methylcellulose in water. POLYMER 2006. [DOI: 10.1016/j.polymer.2005.12.049] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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20
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Couderc-Azouani S, Sidhu J, Thurn T, Xu R, Bloor DM, Penfold J, Holzwarth JF, Wyn-Jones E. Binding of sodium dodecyl sulfate and hexaethylene glycol mono-n-dodecyl ether to the block copolymer L64: electromotive force, microcalorimetry, surface tension, and small angle neutron scattering investigations of mixed micelles and polymer/micellar surfactant complexes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:10197-208. [PMID: 16229545 DOI: 10.1021/la047312q] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The interactions of sodium dodecyl sulfate (SDS) with the triblock copolymer L64 (EO13-PO30-EO13) and hexaethylene glycol mono-n-dodecyl ether (C12EO6) were studied using electromotive force, isothermal titration microcalorimetry, differential scanning microcalorimetry, and surface tension measurements. In certain regions of binding, mixed micelles are formed, and here we could evaluate an interaction parameter using regular solution theory. The mixed micelles of L64 with both SDS and C12EO6 exhibit synergy. When L64 is present in its nonassociated state, it forms polymer/micellar SDS complexes at SDS concentrations above the critical aggregation concentration (cac). The cac is well below the critical micellar concentration (cmc) of pure SDS, and a model suggesting how bound micelles are formed at the cac in the presence of a polymer is described. The interaction of nonassociated L64 with C12EO6 is a very rare example of strong binding between a nonionic surfactant and a nonionic polymer, and C12EO6/L64 mixed micelles are formed. We also carried out small angle neutron scattering measurement to determine the structure of the monomeric polymer/micellar SDS complex, as well as the mixed L64/C12EO6 aggregates. In these experiments, contrast matching was achieved by using the h and d forms of SDS, as well as C12EO6. During the early stages of the formation of polymer-bound SDS micelles, SDS aggregates with aggregation numbers of approximately 20 were found and such complexes contain 4-6 bound L64 monomers. The L64/C12EO6 data confirmed the existence of mixed micelles, and structural information involving the composition of the mixed micelle and the aggregation numbers were evaluated.
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Affiliation(s)
- S Couderc-Azouani
- Fritz-Haber Institut der Max-Planck Gesellschaft, Faradayweg 4-6, D-14195 Berlin-Dahlem, Germany
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Tellinghuisen J. Optimizing Experimental Parameters in Isothermal Titration Calorimetry. J Phys Chem B 2005; 109:20027-35. [PMID: 16853587 DOI: 10.1021/jp053550y] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In isothermal titration calorimetry, the statistical precisions with which the equilibrium constant (K) and reaction enthalpy (DeltaH degrees ) can be estimated from data for 1:1 binding depend on a number of quantities, key among them being the products c identical with K[M](0) and h identical with DeltaH degrees [M](0), the stoichiometry range (R(m)(), ratio of total titrant X to total titrate M after the last injection), and the number of injections of titrant. A study of the statistical errors as functions of these quantities leads to the following prescription for optimizing throughput and precision: (1) Make 10 injections of titrant. (2) Set the concentrations in accord with the empirical equation R(m)() = 6.4/c(0.2) + 13/c (but no smaller than 1.1). (3) Make the starting concentration [M](0) as large as possible within the large-signal limits of the instrumentation but limited to c < 10(3) for estimating K. With this procedure, both K and [M](0) are predicted to have relative standard errors <1% over large ranges of K. Systematic errors in the concentrations, [X](0) and [M](0), are fully compensated by the "site number" or stoichiometry parameter (n). On the other hand, altering and freezing any of the fit parameters leads to a deterioration of the fit quality and to predictable changes in the other parameters. Fit divergence at very small c is avoidable through a simple redefinition of the fit parameters; however, unless n can be fixed from other information, DeltaH degrees may be statistically ill-defined in this region.
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Affiliation(s)
- Joel Tellinghuisen
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, USA.
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Bernazzani L, Borsacchi S, Catalano D, Gianni P, Mollica V, Vitelli M, Asaro F, Feruglio L. On the Interaction of Sodium Dodecyl Sulfate with Oligomers of Poly(Ethylene Glycol) in Aqueous Solution. J Phys Chem B 2004. [DOI: 10.1021/jp049673k] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Luca Bernazzani
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35 − I-56126 Pisa, Italy, and Dipartimento di Chimica, Università di Trieste, Via L. Giorgeri 1-I-34127 Trieste, Italy
| | - Silvia Borsacchi
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35 − I-56126 Pisa, Italy, and Dipartimento di Chimica, Università di Trieste, Via L. Giorgeri 1-I-34127 Trieste, Italy
| | - Donata Catalano
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35 − I-56126 Pisa, Italy, and Dipartimento di Chimica, Università di Trieste, Via L. Giorgeri 1-I-34127 Trieste, Italy
| | - Paolo Gianni
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35 − I-56126 Pisa, Italy, and Dipartimento di Chimica, Università di Trieste, Via L. Giorgeri 1-I-34127 Trieste, Italy
| | - Vincenzo Mollica
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35 − I-56126 Pisa, Italy, and Dipartimento di Chimica, Università di Trieste, Via L. Giorgeri 1-I-34127 Trieste, Italy
| | - Matteo Vitelli
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35 − I-56126 Pisa, Italy, and Dipartimento di Chimica, Università di Trieste, Via L. Giorgeri 1-I-34127 Trieste, Italy
| | - Fioretta Asaro
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35 − I-56126 Pisa, Italy, and Dipartimento di Chimica, Università di Trieste, Via L. Giorgeri 1-I-34127 Trieste, Italy
| | - Luigi Feruglio
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35 − I-56126 Pisa, Italy, and Dipartimento di Chimica, Università di Trieste, Via L. Giorgeri 1-I-34127 Trieste, Italy
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