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Jianbin Huang - One of the best experts on this subject based on the ideXlab platform.
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formation and phase transition of hydrogel in a zwitterionic anionic Surfactant System
RSC Advances, 2015Co-Authors: Jianbin Huang, Haiming Fan, Shuzhi Zhao, Haijian Fan, Wanli KangAbstract:The phase behavior and microstructure in a mixture of the zwitterionic Surfactant N-hexadecyl-N,N-dimethyl-3-ammonio-1-propane sulfonate (HDPS) and anionic Surfactant sodium dodecylsulfate (SDS) were studied. Analysis of its macroscopic appearance, tube inversion testing and rheological measurements were employed to characterize its phase behavior, and it was found that a hydrogel formed in an appropriate total concentration (CT) and molar percentage of SDS (XSDS) at 25 °C for HDPS/SDS Systems. Microstructures in the hydrogel were identified to be long wormlike micelles and small spherical vesicles, using transmission electron microscopy (TEM). The coexistence of wormlike micelles and small vesicles brings an appropriate packing parameter (p), which indicates that the wormlike micelles reached a sufficient length and degree of entanglement to form the three-dimensional elastic hydrogel. The HDPS/SDS hydrogel transforms into a viscoelastic sol upon increasing the temperature, and the determined gel–sol transition temperature (Tg–s) has been determined to be around 30 °C, using optical and rheological methods. Besides, adding salt causes the wormlike micelles to lengthen and the rheological properties of the solution to change, such that it may even induce a sol–gel phase transition in the mixed zwitterionic and anionic Surfactant System.
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the evolution of self assemblies in the mixed System of oleic acid diethylenetriamine based on the transformation of electrostatic interactions and hydrogen bonds
Soft Matter, 2014Co-Authors: C T Zhou, Xinhao Cheng, Jianbin Huang, Oudi Zhao, Shuai Liu, Chenjiang Liu, Jide WangAbstract:With the aid of pH variation, the fine control of the electrostatic interaction and hydrogen bond was realised in the mixed System of oleic acid and diethylenetriamine. Owing to the transformation of the intermolecular interactions, the corresponding building blocks changed from DETA2+@2OA−via the coexistence of DETA@2OA− and DETA+@OA− to DETA@2OA−. Therefore, diverse microstructures and phase behaviors in this mixed Surfactant System were obtained at the different pH values. It is found that the fine control of the electrostatic interaction and hydrogen bond is efficient for tailoring the self-assembled structures in this cationic–anionic Surfactant System, including vesicles, bilayers, networks formed by aggregated vesicles and fibers.
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microstructures and rheological dynamics of viscoelastic solutions in a catanionic Surfactant System
Journal of Colloid and Interface Science, 2009Co-Authors: Haiqing Yin, Yiyang Lin, Jianbin HuangAbstract:Viscoelastic solutions formed in a catanionic Surfactant System of dodecyltriethylammonium bromide (DTEAB)/sodium dodecylsulfate (SDS) at the molar ratio of 27/73 were Systematically studied using a combination of rheology and dynamic light scattering (DLS). Wormlike micelles began to form above the total Surfactant concentration (C(total)) of 120 mM by the growth of small cylindrical micelles. Subsequently the System was found to exhibit linear viscoelasticity with characteristic of a Maxwell fluid in the intermediate concentration range of 170-210 mM, which arose from a 3D entangled network of wormlike micelles. At higher Surfactant concentrations, a transition from linear micelles to branched structures probably took place. Finally and significantly, the effect of the Surfactant headgroup on the rheological property of catanionic Surfactant mixtures was discussed.
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ph regulated molecular self assemblies in a cationic anionic Surfactant System from a 1 2 Surfactant pair to a 1 1 Surfactant pair
Langmuir, 2008Co-Authors: Yiyang Lin, Xue Han, Xinhao Cheng, Jianbin Huang, Dehai LiangAbstract:With the aid of pH variation, direct transformation of a “1−1” cationic−anionic Surfactant pair to a “1−2” cationic−anionic Surfactant pair was attained in the System of cetyltrimethylammonium bromide and n-decylphosphoric acid. Owing to the transformation of a “1−1” pair to a “1−2” pair, diverse microstructures and peculiar phase behavior in this cationic−anionic Surfactant mixture was obtained at different pH. It is proposed that pH can be manipulated for effectively tailoring the self-assembled organization in this cationic−anionic Surfactant System, including spherical micelle, wormlike micelle, vesicle, and lamellar structure. In contrast to the conventional “1−1” Surfactant pair, the “1−2” cationic−anionic Surfactant pair exhibits unexpectedly weak aggregating ability. It is suggested that the hydrated volume of Surfactant headgroup should be taken into consideration to better elucidate the self-assembly behavior of these “1−2” cationic−anionic Surfactant mixtures.
Conxita Solans - One of the best experts on this subject based on the ideXlab platform.
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stability of oil in water paraffin emulsions prepared in a mixed ionic nonionic Surfactant System
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2011Co-Authors: J Vilasau, Conxita Solans, M J Gomez, J Dabrio, R Mujikagarai, Jordi EsquenaAbstract:Abstract In emulsions, a combination of steric and electrostatic stabilization is often required, to increase kinetic stability against time, shear and electrolytes, generally achieved by ionic/nonionic Surfactant mixtures. However, many aspects on stability mechanisms, using these mixed Surfactant Systems, remain unknown. In this context, the main objective of the present work is to study the influence of the Surfactant mixing ratio and the emulsification process on stability of paraffin emulsions. A high pressure homogenizer was used to prepare the emulsions and their stability was evaluated against shear, produced in a pipeline circuit, freeze–thaw cycles and electrolytes. The results show that the emulsions possess high stability against freeze–thaw cycles, moderate stability against shear produced in a pipeline circuit and low stability against electrolyte concentration. A simulation of the interaction potential between particles, based on DLVO equations, was performed and the theoretical results were compared to experimental data. It was found that the stability mechanism is mainly electrostatic and it is consistent with DLVO theory of colloidal stability.
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phase behaviour of a mixed ionic nonionic Surfactant System used to prepare stable oil in water paraffin emulsions
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2011Co-Authors: J Vilasau, Conxita Solans, M J Gomez, J Dabrio, R Mujikagarai, Jordi EsquenaAbstract:Abstract The phase behaviour of a mixed Surfactant System was studied in order to determine the role of Surfactants in the stability of paraffin emulsions. The study was carried out by means of phase diagrams. The different phases were characterized by Small and Wide Angle X-ray Scattering (SAXS/WAXS), Polarized Optical Microscopy (POM) and Differential Scanning Calorimetry (DSC). The results showed that the nonionic and ionic Surfactants, used in industry for paraffin emulsions, possess high Krafft points and both form lamellar interdigitated gel structures. Phase behaviour of the water/mixed Surfactant pseudoternary System indicated that, lamellar liquid crystalline aggregates are formed at very diluted Surfactant concentrations (≈98 wt% water), even at low nonionic/ionic Surfactant weight ratio (10/90). Therefore, lamellar liquid crystalline aggregates coexist with excess water, at the Surfactant compositions used to obtain stable paraffin emulsions (2–4 wt% of mixed Surfactant). Theses aggregates could contribute to the high kinetic stability of the paraffin emulsions.
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nano emulsions preparation by low energy methods in an ionic Surfactant System
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2006Co-Authors: Isabel Sole, Alicia Maestro, C M Pey, C Gonzalez, Conxita Solans, J M GutierrezAbstract:Abstract The emulsion inversion point method was used to form nano-emulsions in the ionic System water/oleic acid–potassium oleate–C 12 E 10 /hexadecane. Potassium hydroxide solutions were added to oleic acid–C 12 E 10 /hexadecane solutions at constant temperature (25 °C) in order to obtain nano-emulsions at 80% water concentration, with a stoichiometric relation of oleic acid and KOH at this point. So, the ionic Surfactant (the potassium oleate) was formed along the emulsification path. The influence of the phases present during the emulsification process on nano-emulsion droplet size was analized. The results show that the smallest droplet size is obtained when along the emulsification path and near the nano-emulsion region the equilibrium is achieved with all the oil dissolved in a phase, in this case in a cubic liquid crystalline phase. It has also been found that the most probable breakdown mechanism of the nano-emulsions formed is Ostwald Ripening.
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optimization of nano emulsion preparation by low energy methods in an ionic Surfactant System
Langmuir, 2006Co-Authors: Isabel Sole, Alicia Maestro, C Gonzalez, Conxita Solans, J M GutierrezAbstract:The low-energy emulsification method Emulsion Inversion Point (EIP) was used to prepare O/W nano-emulsions in the W/potassium oleate−oleic acid−C12E10/hexadecane ionic System. This method had not practically been used in ionic Systems up to now. The resulting droplet sizes, much smaller than those obtained with the high-energy emulsification methods, depend on the composition (formulation variables) and preparation variables (addition and mixing rate). Phase diagrams, rheology measurements, and experimental designs applied to nano-emulsion droplet sizes obtained were combined to study the formation of these nano-emulsions. To obtain small droplet sizes, it is necessary to cross a direct cubic liquid crystal phase along the emulsification path, and it is also crucial to remain in this phase long enough to incorporate all of the oil into the liquid crystal. When nano-emulsion forms, the oil is already intimately mixed with all of the components, and it only has to be redistributed. Results show that the sma...
Jordi Esquena - One of the best experts on this subject based on the ideXlab platform.
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stability of oil in water paraffin emulsions prepared in a mixed ionic nonionic Surfactant System
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2011Co-Authors: J Vilasau, Conxita Solans, M J Gomez, J Dabrio, R Mujikagarai, Jordi EsquenaAbstract:Abstract In emulsions, a combination of steric and electrostatic stabilization is often required, to increase kinetic stability against time, shear and electrolytes, generally achieved by ionic/nonionic Surfactant mixtures. However, many aspects on stability mechanisms, using these mixed Surfactant Systems, remain unknown. In this context, the main objective of the present work is to study the influence of the Surfactant mixing ratio and the emulsification process on stability of paraffin emulsions. A high pressure homogenizer was used to prepare the emulsions and their stability was evaluated against shear, produced in a pipeline circuit, freeze–thaw cycles and electrolytes. The results show that the emulsions possess high stability against freeze–thaw cycles, moderate stability against shear produced in a pipeline circuit and low stability against electrolyte concentration. A simulation of the interaction potential between particles, based on DLVO equations, was performed and the theoretical results were compared to experimental data. It was found that the stability mechanism is mainly electrostatic and it is consistent with DLVO theory of colloidal stability.
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phase behaviour of a mixed ionic nonionic Surfactant System used to prepare stable oil in water paraffin emulsions
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2011Co-Authors: J Vilasau, Conxita Solans, M J Gomez, J Dabrio, R Mujikagarai, Jordi EsquenaAbstract:Abstract The phase behaviour of a mixed Surfactant System was studied in order to determine the role of Surfactants in the stability of paraffin emulsions. The study was carried out by means of phase diagrams. The different phases were characterized by Small and Wide Angle X-ray Scattering (SAXS/WAXS), Polarized Optical Microscopy (POM) and Differential Scanning Calorimetry (DSC). The results showed that the nonionic and ionic Surfactants, used in industry for paraffin emulsions, possess high Krafft points and both form lamellar interdigitated gel structures. Phase behaviour of the water/mixed Surfactant pseudoternary System indicated that, lamellar liquid crystalline aggregates are formed at very diluted Surfactant concentrations (≈98 wt% water), even at low nonionic/ionic Surfactant weight ratio (10/90). Therefore, lamellar liquid crystalline aggregates coexist with excess water, at the Surfactant compositions used to obtain stable paraffin emulsions (2–4 wt% of mixed Surfactant). Theses aggregates could contribute to the high kinetic stability of the paraffin emulsions.
Isabel Sole - One of the best experts on this subject based on the ideXlab platform.
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nano emulsions preparation by low energy methods in an ionic Surfactant System
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2006Co-Authors: Isabel Sole, Alicia Maestro, C M Pey, C Gonzalez, Conxita Solans, J M GutierrezAbstract:Abstract The emulsion inversion point method was used to form nano-emulsions in the ionic System water/oleic acid–potassium oleate–C 12 E 10 /hexadecane. Potassium hydroxide solutions were added to oleic acid–C 12 E 10 /hexadecane solutions at constant temperature (25 °C) in order to obtain nano-emulsions at 80% water concentration, with a stoichiometric relation of oleic acid and KOH at this point. So, the ionic Surfactant (the potassium oleate) was formed along the emulsification path. The influence of the phases present during the emulsification process on nano-emulsion droplet size was analized. The results show that the smallest droplet size is obtained when along the emulsification path and near the nano-emulsion region the equilibrium is achieved with all the oil dissolved in a phase, in this case in a cubic liquid crystalline phase. It has also been found that the most probable breakdown mechanism of the nano-emulsions formed is Ostwald Ripening.
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optimization of nano emulsion preparation by low energy methods in an ionic Surfactant System
Langmuir, 2006Co-Authors: Isabel Sole, Alicia Maestro, C Gonzalez, Conxita Solans, J M GutierrezAbstract:The low-energy emulsification method Emulsion Inversion Point (EIP) was used to prepare O/W nano-emulsions in the W/potassium oleate−oleic acid−C12E10/hexadecane ionic System. This method had not practically been used in ionic Systems up to now. The resulting droplet sizes, much smaller than those obtained with the high-energy emulsification methods, depend on the composition (formulation variables) and preparation variables (addition and mixing rate). Phase diagrams, rheology measurements, and experimental designs applied to nano-emulsion droplet sizes obtained were combined to study the formation of these nano-emulsions. To obtain small droplet sizes, it is necessary to cross a direct cubic liquid crystal phase along the emulsification path, and it is also crucial to remain in this phase long enough to incorporate all of the oil into the liquid crystal. When nano-emulsion forms, the oil is already intimately mixed with all of the components, and it only has to be redistributed. Results show that the sma...
J M Gutierrez - One of the best experts on this subject based on the ideXlab platform.
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nano emulsions preparation by low energy methods in an ionic Surfactant System
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2006Co-Authors: Isabel Sole, Alicia Maestro, C M Pey, C Gonzalez, Conxita Solans, J M GutierrezAbstract:Abstract The emulsion inversion point method was used to form nano-emulsions in the ionic System water/oleic acid–potassium oleate–C 12 E 10 /hexadecane. Potassium hydroxide solutions were added to oleic acid–C 12 E 10 /hexadecane solutions at constant temperature (25 °C) in order to obtain nano-emulsions at 80% water concentration, with a stoichiometric relation of oleic acid and KOH at this point. So, the ionic Surfactant (the potassium oleate) was formed along the emulsification path. The influence of the phases present during the emulsification process on nano-emulsion droplet size was analized. The results show that the smallest droplet size is obtained when along the emulsification path and near the nano-emulsion region the equilibrium is achieved with all the oil dissolved in a phase, in this case in a cubic liquid crystalline phase. It has also been found that the most probable breakdown mechanism of the nano-emulsions formed is Ostwald Ripening.
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optimization of nano emulsion preparation by low energy methods in an ionic Surfactant System
Langmuir, 2006Co-Authors: Isabel Sole, Alicia Maestro, C Gonzalez, Conxita Solans, J M GutierrezAbstract:The low-energy emulsification method Emulsion Inversion Point (EIP) was used to prepare O/W nano-emulsions in the W/potassium oleate−oleic acid−C12E10/hexadecane ionic System. This method had not practically been used in ionic Systems up to now. The resulting droplet sizes, much smaller than those obtained with the high-energy emulsification methods, depend on the composition (formulation variables) and preparation variables (addition and mixing rate). Phase diagrams, rheology measurements, and experimental designs applied to nano-emulsion droplet sizes obtained were combined to study the formation of these nano-emulsions. To obtain small droplet sizes, it is necessary to cross a direct cubic liquid crystal phase along the emulsification path, and it is also crucial to remain in this phase long enough to incorporate all of the oil into the liquid crystal. When nano-emulsion forms, the oil is already intimately mixed with all of the components, and it only has to be redistributed. Results show that the sma...