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Abstract
In the search for responsive complexes with potential applications in the formulation of smart dispersed systems such as foams, we hypothesized that a pH-responsive system could be formulated with polyacrylic acid (PAA) mixed with a cationic surfactant, Gemini 12-2-12 (G12). We studied PAA-G12 complexes at liquid–air interfaces by equilibrium and dynamic surface tension, surface rheology, and X-ray reflectometry (XRR). We found that complexes adsorb at the interfaces synergistically, lowering the equilibrium surface tension at surfactant concentrations well below the critical micelle concentration (cmc) of the surfactant. We studied the stability of foams formulated with the complexes as a function of pH. The foams respond reversibly to pH changes: at pH 3.5, they are very stable; at pH > 6, the complexes do not form foams at all. The data presented here demonstrate that foam formation and its pH responsiveness are due to interfacial dynamics.
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Bai J, Xie LY, Yang L, Wang RQ, Chen X, Hu S. Reversed lipid micellar hollow-fiber liquid-phase microextraction of rotigotine in rat plasma. J Chromatogr B Analyt Technol Biomed Life Sci 2021; 1178:122583. [PMID: 34224964 DOI: 10.1016/j.jchromb.2021.122583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/28/2021] [Accepted: 02/01/2021] [Indexed: 11/28/2022]
Abstract
A hollow fiber liquid phase microextraction (HF-LPME) based on a reversed lipid micelle as the extraction phase was proposed and combined with high performance liquid chromatography (HPLC) for the determination of rotigotine in biological matrix. In the proposed procedure, pieces of hollow fibers were fastened on a magnetic stir bar using a thread to provide better precision. Rotigotine was extracted from 5 mL of diluted plasma sample phase with pH 6 into reversed lipid micelle (5 mmol/L of dipalmitoyl phosphatidyl choline in n-octanol/water) impregnated in both the wall pores and the lumen of the hollow fiber. After the extraction at 900 rpm and room temperature for 30 min, the acceptor phase of reversed lipid micelle was collected for HPLC analysis. Various parameters affecting the extraction efficiency, such as type of surfactant and organic solvent, surfactant concentration, sample phase pH, salt amount, extraction time, stirring rate, and dilution factor of the plasma sample, were investigated and optimized. Furthermore, the formed reversed lipid micelle was characterized by fluorescence method. Under the optimal conditions, the linear range of rotigotine was between 2 ng/mL and 100 ng/mL with determination coefficient (r2) ≥ 0.9913. It is shown from results of method validation that the satisfactory accuracy (the relative errors between -8.5% and 3.3%), precision (the relative standard deviations from 3.8% to 8.9%), stability and matrix effect were obtained. The enrichment factor (EF) of the reversed lipid micelle-based HF-LPME for rotigotine reached 126. And the feasibility of the proposed method was confirmed by the application to the pharmacokinetic study of rotigotine in rat plasma.
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Affiliation(s)
- Jie Bai
- School of Pharmacy, Shanxi Medical University, Taiyuan 030001, PR China
| | - Li-Yuan Xie
- School of Pharmacy, Shanxi Medical University, Taiyuan 030001, PR China
| | - Li Yang
- School of Pharmacy, Shanxi Medical University, Taiyuan 030001, PR China
| | - Run-Qin Wang
- School of Pharmacy, Shanxi Medical University, Taiyuan 030001, PR China
| | - Xuan Chen
- School of Pharmacy, Shanxi Medical University, Taiyuan 030001, PR China
| | - Shuang Hu
- School of Pharmacy, Shanxi Medical University, Taiyuan 030001, PR China.
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Dominguez C, Leyes MF, Cuenca VE, Ritacco HA. Scaling Laws in the Dynamics of Collapse of Single Bubbles and 2D Foams. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:15386-15395. [PMID: 33284632 DOI: 10.1021/acs.langmuir.0c02971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Avalanches of rupturing bubbles play an important role in the dynamics of collapse of macroscopic liquid foams. We hypothesized that the occurrence of cascades of rupturing bubbles in foams depends, at least in part, on the power released during the rupture of a bubble. In this paper, we present results on the dynamics of single bubble bursting obtained by analyzing the pressure wave (sound) emitted by the bubble when collapsing. We found that the released energy varies linearly with bubble size, the frequency of the emitted sound follows a power law with exponent 3/2 (compatible with the Helmholtz resonator model) and the duration of a rupturing event seems to be independent of bubble size. To correlate the dynamics of individual bubbles with the dynamics of foams, we studied the occurrence of avalanches on bubble rafts and found that the phenomenon appears to be a self-organized criticality (SOC) process. The distribution functions for the size of the avalanches are a power law with exponents between 2 and 3, depending on the surfactant concentration. The distribution of times between ruptures also follows a power law with exponents close to 1, independently of the surfactant concentration.
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Affiliation(s)
- Claudia Dominguez
- Instituto de Física del Sur (IFISUR), Departamento de Física, Universidad Nacional del Sur (UNS), CONICET, Av. L. N. Alem 1253, B8000CPB, Bahía Blanca, Argentina
| | - Marcos Fernández Leyes
- Instituto de Física del Sur (IFISUR), Departamento de Física, Universidad Nacional del Sur (UNS), CONICET, Av. L. N. Alem 1253, B8000CPB, Bahía Blanca, Argentina
| | - Victor E Cuenca
- Instituto de Física del Sur (IFISUR), Departamento de Física, Universidad Nacional del Sur (UNS), CONICET, Av. L. N. Alem 1253, B8000CPB, Bahía Blanca, Argentina
| | - Hernán A Ritacco
- Instituto de Física del Sur (IFISUR), Departamento de Física, Universidad Nacional del Sur (UNS), CONICET, Av. L. N. Alem 1253, B8000CPB, Bahía Blanca, Argentina
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Adsorption Kinetics of a Cationic Surfactant Bearing a Two-Charged Head at the Air-Water Interface. COATINGS 2020. [DOI: 10.3390/coatings10020095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We studied the dynamics of adsorption at the air-water interface of a cationic surfactant bearing two charges, Gemini 12-2-12, at concentrations below and above the critical micelle concentration (cmc). We used maximum bubble pressure and Wilhelmy plate techniques in order to access all time scales in the adsorption process. We found that the adsorption dynamics are controlled by diffusion at the initial stage of the adsorption process (milliseconds) and it is kinetically controlled by an electrostatic barrier (minute) approaching the equilibrium surfactant surface concentration. Between these two extremes, we found several relaxation phenomena, all following exponential decays with characteristic times spanning from one to hundreds of seconds. By means of time-resolved surface potential measurements, we show that these processes involve charge redistribution within the interfacial region. The surface tension data are analyzed and interpreted in the framework of the free energy approach.
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Cuenca VE, Ferna Ndez Leyes M, Falcone RDO, Correa NM, Langevin D, Ritacco HN. Interfacial Dynamics and Its Relations with ?Negative? Surface Viscosities Measured at Water?Air Interfaces Covered with a Cationic Surfactant. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:8333-8343. [PMID: 31124690 DOI: 10.1021/acs.langmuir.9b00534] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We studied the dynamics of a cationic surfactant monolayer, Gemini 12-2-12, at the air?water interface for surfactant aqueous solutions at concentrations below the critical micelle concentration. We present surface rheology experiments performed in a Langmuir trough by the oscillatory barrier technique. From these, we found negative surface viscosities at certain frequencies. We demonstrate that this unphysical result is a consequence of an unconsidered surfactant dynamics within the interfacial region. By surface pressure relaxation experiments, after a sudden modification of the interfacial area and by dynamic surface tension and surface potential measurements, several relaxation phenomena and relaxation times were identified. We found that surfactant adsorption and desorption processes are asymmetric: the characteristic times and the number of processes involved in the mechanisms of adsorption and desorption are different. This asymmetry invalidates the usual data analysis procedure that leads to the negative viscosities. Similar mechanisms could be at the origin of the negative viscosities reported in other systems, a possibility that remains to be explored.
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Affiliation(s)
- Victor E Cuenca
- Instituto de Fi?sica del Sur (IFISUR), Departamento de Fi?sica , Universidad Nacional del Sur (UNS), CONICET , Av. L. N. Alem 1253 , B8000CPB Bahi?a Blanca , Argentina
| | - Marcos Ferna Ndez Leyes
- Instituto de Fi?sica del Sur (IFISUR), Departamento de Fi?sica , Universidad Nacional del Sur (UNS), CONICET , Av. L. N. Alem 1253 , B8000CPB Bahi?a Blanca , Argentina
| | - R Dari O Falcone
- Departamento de Qui?mica , Universidad Nacional del Rio Cuarto , Agencia Postal #3, CP X5804BYA Ri?o Cuarto , Argentina
- Instituto para el Desarrollo Agroindustrial y de la Salud (IDAS, UNRC-CONICET) , Universidad Nacional de Ri?o Cuarto , Ruta 36, Km 601 , X5804ZAB Ri?o Cuarto , Co?rdoba , Argentina
| | - N Mariano Correa
- Departamento de Qui?mica , Universidad Nacional del Rio Cuarto , Agencia Postal #3, CP X5804BYA Ri?o Cuarto , Argentina
- Instituto para el Desarrollo Agroindustrial y de la Salud (IDAS, UNRC-CONICET) , Universidad Nacional de Ri?o Cuarto , Ruta 36, Km 601 , X5804ZAB Ri?o Cuarto , Co?rdoba , Argentina
| | - Dominique Langevin
- Laboratoire de Physique des Solides , Universite? Paris Sud , Ba?t. 510, Orsay 91405 , France
| | - Herna N Ritacco
- Instituto de Fi?sica del Sur (IFISUR), Departamento de Fi?sica , Universidad Nacional del Sur (UNS), CONICET , Av. L. N. Alem 1253 , B8000CPB Bahi?a Blanca , Argentina
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Abulateefeh SR, Al-Adhami GK, Alkawareek MY, Alkilany AM. Controlling the internal morphology of aqueous core-PLGA shell microcapsules: promoting the internal phase separation via alcohol addition. Pharm Dev Technol 2019; 24:671-679. [DOI: 10.1080/10837450.2018.1558238] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Peng J, Deng J, Huang X, Sun P, Deng W. Aggregation-Enhanced Emission of Fluorescent-Gemini Surfactants with High Photostability for Cell-Membrane Imaging. J SURFACTANTS DETERG 2018. [DOI: 10.1002/jsde.12036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jinwen Peng
- Guangxi Ministry-Province Jointly-Constructed Cultivation Base for State Key Laboratory of Processing for Non-Ferrous Metal and Featured Materials; Guilin University of Technology; Guilin 541004 China
| | - Junjie Deng
- Guangxi Ministry-Province Jointly-Constructed Cultivation Base for State Key Laboratory of Processing for Non-Ferrous Metal and Featured Materials; Guilin University of Technology; Guilin 541004 China
| | - Xuebing Huang
- Guangxi Ministry-Province Jointly-Constructed Cultivation Base for State Key Laboratory of Processing for Non-Ferrous Metal and Featured Materials; Guilin University of Technology; Guilin 541004 China
| | - Pengfei Sun
- Key Laboratory for Organic Electronics & Information Displays, Institute of Advanced Materials; Nanjing University of Posts & Telecommunications; Nanjing 210046 China
| | - Weixing Deng
- Guangxi Ministry-Province Jointly-Constructed Cultivation Base for State Key Laboratory of Processing for Non-Ferrous Metal and Featured Materials; Guilin University of Technology; Guilin 541004 China
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Villa CC, Silber JJ, Falcone RD, Correa NM. Subtleties of catanionic surfactant reverse micelle assemblies revealed by a fluorescent molecular probe. Methods Appl Fluoresc 2017; 5:044001. [PMID: 28653961 DOI: 10.1088/2050-6120/aa7b64] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In this work, the absorption and emission behavior of the cationic hemicyanine trans-4-[4-(dimethylamino)styryl]-N-methylpyridinium iodide (HC) in reverse micelles (RMs) formed by the catanionic surfactants benzyl-n-hexadecyldimethylammonium-1,4-bis-2-ethylhexylsulfosuccinate (AOT-BHD) and cetyltrimethylammonium-1,4-bis-2-ethylhexylsulfosuccinate (AOT-CTA) have been investigated. Our results show that the spectroscopic behavior of HC changes when the dye is dissolved in AOT-BHD or in AOT-CTA RMs. While HC undergoes an intramolecular charge-transfer process upon excitation in AOT-CTA RMs, in AOT-BHD RMs this process is inhibited due to a specific interaction between HC and the polar head group of the BHD+ cation. This implies that the chemical structure of CTA+ and BHD+ cations has a large impact on the excited stated from which HC emission occurs. Additionally, the structural difference between the two cations impacts on the water-RM interface interaction, which provides a way of controlling the solvation process in these RMs. Furthermore, differences in the interfacial fluidity between the two catanionic RMs is observed, a result that is particularly interesting with regard to these systems being used as nanoreactors.
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Lépori CMO, Silber JJ, Falcone RD, Correa NM. Improvement of the amphiphilic properties of a dialkyl phosphate by creation of a protic ionic liquid-like surfactant. RSC Adv 2017. [DOI: 10.1039/c7ra08907d] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Imim-DEHP, an interesting protic IL-like surfactant to create RMs in aliphatic and aromatic non-polar solvents and unilamellar vesicles in water.
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Affiliation(s)
- Cristian M. O. Lépori
- Departamento de Química
- Universidad Nacional de Río Cuarto
- C.P. X5804BYA Río Cuarto
- Argentina
| | - Juana J. Silber
- Departamento de Química
- Universidad Nacional de Río Cuarto
- C.P. X5804BYA Río Cuarto
- Argentina
| | - R. Darío Falcone
- Departamento de Química
- Universidad Nacional de Río Cuarto
- C.P. X5804BYA Río Cuarto
- Argentina
| | - N. Mariano Correa
- Departamento de Química
- Universidad Nacional de Río Cuarto
- C.P. X5804BYA Río Cuarto
- Argentina
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