Beijing FLUOBON Surfactant Institute

Beijing, China

Beijing FLUOBON Surfactant Institute

Beijing, China
SEARCH FILTERS
Time filter
Source Type

Xiao Z.-B.,Nankai University | Xing H.,Beijing FLUOBON Surfactant Institute | Xiao J.-X.,Beijing FLUOBON Surfactant Institute
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2017

The disodium salt of 1-sulfo-cyclohexanecarboxylic acid (SCCA) was characterized by 1H and 13C NMR. The effects of SCCA on the surface activity of two high-Krafft-point fluorinated surfactants (potassium and sodium salts of perfluorooctanesulfonic acid, KPFOS and NaPFOS) and a conventional hydrogenated surfactant (sodium dodecylbenzene sulfonate, SDBS) were studied at room temperature. When SCCA was added, the effectiveness of KPFOS and NaPFOS in surface tension reduction was both greatly enhanced and KPFOS showed higher efficiency in surface tension reduction than NaPFOS. In particular, with the assistance of SCCA the minimum surface tension of fluorinated surfactants could even be as low as ∼18mN/m at 25°C. In contrast, the surface activity of SDBS was significantly reduced by SCCA, with the critical micelle concentation (cmc) largely increased. As a conclusion, the SCCA could act as an effective hydrotropic agent and it was able to recover the inherent character of KPFOS and NaPFOS as highly surface-active fluorinated surfactants by increasing their solubility. While for SDBS which was already soluble at room temperature, SCCA lowered the surface activity of SDBS. In addition, a preliminary study of application showed that SCCA was a qualified hydrotropic agent in formulations for industrial detergent and enhanced oil recovery. © 2017 Elsevier B.V.


Xing H.,CAS Beijing National Laboratory for Molecular | Xing H.,Beijing FLUOBON Surfactant Institute | Lin S.-S.,CAS Beijing National Laboratory for Molecular | Xiao J.-X.,CAS Beijing National Laboratory for Molecular | Xiao J.-X.,Beijing FLUOBON Surfactant Institute
Journal of Chemical and Engineering Data | Year: 2010

The interactions between α-cyclodextrin (α-CD) and an equimolar mixture of the anionic hydrogenated and fluorinated surfactants sodium decyl sulfate (SDeS) and sodium perfluorooctanoate (SPFO), respectively, were studied by 1H and 19F NMR spectroscopy. It was directly proved that α-CD preferentially included the hydrogenated surfactant in such a surfactant mixture, although SDeS and SPFO showed almost the same hydrophobicity. The added α-CD formed 1:1 and 2:1 complexes with SDeS, but SPFO showed only a weak association with α-CD after the near saturation of inclusion of SDeS. Such selectivity of α-CD is contrary to that of β-CD, as shown in our previous work in which β-CD preferentially included the fluorinated surfactant in an SDeS/SPFO mixture. This selectivity of α-CD could be ascribed to the better fit between the cavity of α-CD and the hydrocarbon chain. It is consistent with the equilibrium constants (K) for the inclusion complexes in the solution. A peculiar trend of chemical shift variation was noted in mixtures of α-CD with the single surfactant SDeS: the chemical shift of β-CH2 increased rapidly while ω-CH3 showed a smaller ascent to declivity, until both of them reached a plateau. The binding constant for the formation of the 2:1 α-CD/SDeS complex (K2) was found to be relatively large, as determined by the NMR investigation. © 2010 American Chemical Society.


Chen Z.,Beijing Normal University | Li X.-W.,Beijing Normal University | Zhao K.-S.,Beijing Normal University | Xiao J.-X.,Beijing FLUOBON Surfactant Institute | Yang L.-K.,Beijing Normal University
Journal of Physical Chemistry B | Year: 2011

The interaction between poly(diallyldimethylammonium chloride) (PDADMAC) and ionic surfactant sodium decyl sulfate (C10SO4Na) in aqueous solution was investigated by means of dielectric relaxation spectroscopy. To better understand the interaction, the dielectric behaviors of PDADMAC solution and C10SO4Na solution were also separately studied. For PDADMAC solution, two relaxations were observed, which were attributed to the polarization of loosely bound counterions along the directions parallel and perpendicular to the PDADMAC chain. For C 10SO4Na solution, dielectric relaxation was observed at submicellar concentrations, which is ascribed to the counterion diffusion around premicelles. For the aqueous solutions of a PDADMAC/C10SO 4Na mixture with different C10SO4Na concentrations, three surfactant concentration regions characterized by different dielectric behaviors were observed. The dielectric behavior in different regions was discussed through comparing it with that of PDADMAC solution and C10SO4Na solution. The possible interaction pattern and microstructure of the PDADMAC/C10SO4Na complex were proposed on the basis of the dielectric behavior. © 2011 American Chemical Society.


Chen L.,CAS Beijing National Laboratory for Molecular | Xing H.,CAS Beijing National Laboratory for Molecular | Xing H.,Beijing FLUOBON Surfactant Institute | Yan P.,CAS Beijing National Laboratory for Molecular | And 3 more authors.
Soft Matter | Year: 2011

Effects of alkali metal halides (NaX, X = F-, Cl-, Br-, I-; KX, X = Cl-, Br-, I -; and CsCl) on the morphology of the aggregates of decyltriethylammonium bromide and sodium decylsulfonate (C10NE-C 10SO3) mixtures with equimolar ratios were studied by static/dynamic light scattering and viscosity measurements. The average hydrodynamic radii of the aggregates, the apparent aggregation number, and the relative viscosity as functions of both the concentrations of surfactants and added salts were investigated, respectively. It showed that the addition of a small amount of NaX (e.g., 0.1 M) had only small effects on the C 10NE-C10SO3 vesicles. However, striking anion specificity, which differed anomalously with the anions of salts varying from F- to I-, was observed when large amounts of NaX (e.g., 1 M) were added. The size of the C10NE-C10SO3 aggregates was normally increased and then a liquid-liquid phase separation occurred with the addition of NaF; meanwhile, the addition of NaCl had little effect on the C10NE-C10SO3 aggregates under experimental conditions; however, the size of the C10NE-C 10SO3 aggregates was abnormally decreased when high concentrations of NaBr or NaI (up to 2 M) were added, implying a vesicle-to-micelle transition which might be due to a decrease in the intramicellar attraction between oppositely charged headgroups by electrical shielding, and the mixtures still remained homogeneous. A cation specificity of added salts was also observed with the increase of the ionic radii from Na + to Cs+. However, it was noted that the influence of increasing the ionic radii of cations on the aggregate size was not as pronounced as that of anions in the presence of high concentrations of salts. The aggregates of C10NE-C10SO3 became a little smaller when concentrated alkali metal halides with bigger cations were added into this homogeneous equimolar cationic-anionic surfactant mixture. Both the observed cation and anion specificities were consistent with the Hofmeister series. © 2011 The Royal Society of Chemistry.


Xing H.,Beijing FLUOBON Surfactant Institute | Xing H.,CAS Beijing National Laboratory for Molecular | Yan P.,CAS Beijing National Laboratory for Molecular | Xiao J.-X.,Beijing FLUOBON Surfactant Institute | Xiao J.-X.,CAS Beijing National Laboratory for Molecular
Soft Matter | Year: 2013

The aqueous solutions of tetraalkylammonium perfluorooctanoates (C 7F15COON(CnH2n+1)4, n = 1, 2, 3, 4, abbr. TMAPFO, TEAPFO, TPAPFO, TBAPFO) were studied by steady-state and time-resolved fluorescence with pyrene as a probe, and the ammonium perfluorooctanoate (APFO) was also studied as a comparison. Unusual response of pyrene fluorescence was observed. The intensity ratio of the first and third vibronic peaks of pyrene (I1/I3) greatly varied with the counterions for these fluorinated surfactants after their critical micelle concentration (cmc): for TEAPFO, the I1/I3 abnormally increased to a value higher than that of water, while for TBAPFO the I 1/I3 value exhibited a small extent of decease after cmc. However, no significant change of I1/I3 was observed during the micellization of TMAPFO and TPAPFO. The lifetime of pyrene fluorescence (τ0) among the systems of tetraalkylammonium perfluorooctanoates (TAAPFOs) was observed to be increased with the hydrophobicity of counterions. Moreover, the time-resolved fluorescence decay curves of pyrene for all micellar solutions exhibited single exponential decay, suggesting a single environment for pyrene, i.e. each surfactant had a single location of pyrene solubilized in its micelle. The performances of the pyrene probe in concentrated solutions of neat ammonium/tetraalkylammonium chlorides (NH4Cl/TAACls) were also investigated and an unusually high I 1/I3 could be found for tetraethylammonium chloride. It reached a conclusion that pyrene located in the counterion layer of the TAAPFO micelles, which could be ascribed to the hydrophobic interaction and cation-π interaction between pyrene and tetraalkylammonium ions (TAA+) and the immiscibility between pyrene and the fluorocarbon core. This journal is © 2013 The Royal Society of Chemistry.


Zhou H.-T.,China University of Petroleum - East China | Lin S.-S.,CAS Beijing National Laboratory for Molecular | Xing H.,Beijing FLUOBON Surfactant Institute | Gao A.-T.,Beijing Institute of Technology | Xiao J.-X.,Beijing FLUOBON Surfactant Institute
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2013

The effects of different concentrations of sodium thiocyanate (NaSCN) on the homogeneous solution of equimolarly mixed decyltriethylammonium bromide and sodium decylsulfonate (C10NE-C10SO3) were studied by 1H NMR, surface tension and dynamic light scattering (DLS) measurements. For the system of C10NE-C10SO3, the NMR signals were greatly broadened in the micellar concentration region. However, the shape of the NMR peaks for the micellar solutions of C10NE-C10SO3, especially for those protons adjacent to headgroups, recovered to be fine-resolved with the gradual increase of NaSCN concentration. Therefore, the NMR method directly evidenced that the electrostatic attraction between the oppositely charged headgroups in the micellar solution of C10NE-C10SO3 was significantly reduced by NaSCN. The surface tension results showed that both the surface tension at critical micelle concentration (γcmc) and the minimum molecular area in the surface adsorbed layer (Amin) were remarkably increased when NaSCN was added to C10NE-C10SO3. As shown by DLS, the addition of NaSCN could significantly induce the decrease of the aggregate size of C10NE-C10SO3. Both surface tension and DLS results supported the conclusions made by NMR. © 2012 Elsevier B.V.


Li G.-L.,Shandong University | Li G.-L.,Shandong Institute of Light Industry | Gao Y.-A.,Shandong University | Li X.-W.,Shandong University | And 5 more authors.
Journal of Colloid and Interface Science | Year: 2010

N-alkyl perfluorooctanesulfonamides (C8F17SO2NHCnH2n+1, FC8{single bond}HCn, n = 2, 4, 6, 8) were shown to form aggregates in dimethyl sulfoxide (DMSO). Surface tension results revealed that the dissolution of FC8{single bond}HCn reduced the surface tension of DMSO in a manner analogous to common surfactants in aqueous solutions. Maximum surface excess amount (Γmax) and minimum surface area per molecule (Amin) at the air-liquid interface were estimated. Γmax decreases and Amin increases with an increase of the hydrocarbon chain length of FC8{single bond}HCn. Steady-state fluorescence and NMR measurements demonstrated that both fluorocarbon and hydrocarbon chains of FC8{single bond}HCn molecules were incorporated inside the aggregates. UV-vis spectroscopy confirmed the formation of aggregates and determined the critical micelle concentration (cmc) of FC8{single bond}HC6 and FC8{single bond}HC8 solutions. The thermodynamic parameters Δ Gagg 0, Δ Hagg 0, and Δ Sagg 0 for the aggregate formation of FC8{single bond}HCn in DMSO derived from the temperature dependence of the cmc revealed that the aggregate formation is an enthalpy-driven process, which was further confirmed by isothermal titration calorimetry (ITC) measurements. Moreover, the absolute values of Δ Gagg 0 and Δ Hagg 0 increase with an increase of the hydrocarbon chain length of FC8{single bond}HCn at 298 K. © 2009 Elsevier Inc. All rights reserved.


Xing H.,CAS Beijing National Laboratory for Molecular | Xing H.,Beijing FLUOBON Surfactant Institute | Zhou H.-T.,China University of Petroleum - East China | Yu H.-Q.,Beijing FLUOBON Surfactant Institute | And 3 more authors.
Journal of Chemical and Engineering Data | Year: 2011

It is generally considered that complexes of cyclodextrins (CDs) with ordinary surfactants are not surface-active in water. In this work, aqueous mixtures of α-CD, octyltriethylammonium bromide (OTEAB), and sodium perfluorooctanoate (SPFO) were studied by surface tension measurements. Comparison of the experimental results and the simulated ones in the premicellar region showed that the ability of the α-CD/OTEAB complexes to participate in the surface-adsorbed layer was dependent on the overall net charge of the surfactants: for the excess-SPFO system, the α-CD/OTEAB complexes did show a significant contribution to the surface activity of the mixture, but in the system with excess OTEAB, the α-CD/OTEAB complexes were not observed to influence the surface-adsorbed layer. We speculated that the surface-adsorbed layer in the premicellar region might also prefer an electroneutral state, as those cationic-anionic micelles did, and that the α-CD/OTEAB complexes were driven to the surface by electrostatic attractions from the excess oppositely charged SPFO. The calculated results for the surface area per molecule adsorbed at the air-water interface also supported our conclusion. © 2011 American Chemical Society.


Xing H.,CAS Beijing National Laboratory for Molecular | Xing H.,Beijing FLUOBON Surfactant Institute | Yan P.,CAS Beijing National Laboratory for Molecular | Zhao K.-S.,Beijing Normal University | And 2 more authors.
Journal of Chemical and Engineering Data | Year: 2011

The micellization of dodecyltrimethyl/ethyl/propyl/butylammonium bromide (C12NM, C12NE, C12NP, and C12NB) was investigated by electrical conductivity measurements at different temperatures T. In the investigated temperature range, (15 to 45) °C, both the critical micelle concentration (cmc) and the degree of counterion association (β) decreased with the increase of headgroup size. The cmc as a function of T showed a typical U-shaped relationship. The temperature of the minimum of U-shaped curve (Tmin) increased with the incremental chain length in the headgroups, which was the reverse to the previous results for quaternary ammonium surfactants that Tmin decreased with the increment in the hydrophobic tails. The β approximately exhibited a linear decrease with raising T. Nonlinearity was observed both in ln(cmc) versus Nc and in ΔmicG° versus T, where Nc was the carbon number in the headgroups and ΔmicG° was the standard Gibbs energy of micellization. C12NM and C12NE resembled each other in the thermodynamics of micellization, but they behaved considerably differently from either C12NP or C12NB in the dependence of ln(cmc) on Nc, in the decreasing rate of ΔmicG° versus T, and in the variation of thermodynamic properties with T. All of the surfactants exhibited the enthalpy-entropy compensation phenomenon. The large value of standard entropy of micellization (ΔmicS°) of C 12NB compared with the others could be attributed to the strong hydrophobicity of the tributyl headgroup. © 2010 American Chemical Society.


Dou Z.-P.,CAS Beijing National Laboratory for Molecular | Xing H.,CAS Beijing National Laboratory for Molecular | Xing H.,Beijing FLUOBON Surfactant Institute | Xiao J.-X.,CAS Beijing National Laboratory for Molecular | Xiao J.-X.,Beijing FLUOBON Surfactant Institute
Chemistry - A European Journal | Year: 2011

A novel type of surfactants named "host-guest surfactants" were designed and synthesized. The headgroup and hydrophobic tail of the new surfactants are connected by supramolecular interactions rather than covalent bonds. The inclusion complexes of a series of cyclodextrins (CDs) and alkanes/fluoroalkyl-grafted alkanes were synthesized and measured by surface tension, XRD, XPS, TGA, and NMR spectroscopy. The methyl-β-CD/hexadecane complex showed surface activity relative to those conventional hydrogenated surfactants. For the inclusion complex of hydroxypropyl-α-CD/C 8F 17SO 2NHC 8H 17, the structure was locked by subtle intermolecular recognition, which ensured the surprising surface activity similar to common excellent fluorinated surfactants. This surfactant, which was fabricated from nonsurface-active even insoluble components, showed the prospect that its surface activity might also be destroyed by introducing appropriate small species to extrude the guest from the cavity. Surfactants based on host-guest interactions that are the inclusion complexes of substituted cyclodextrins (CD*) and alkanes/fluoroalkyl- grafted alkanes have been designed. CD* played the role of headgroup and the exposed part of the guests acted as the hydrophobic tail. Compared with the shuttle structure of hydrogenated host-guest surfactants, the structure of the fluorinated ones was locked by subtle intermolecular recognition (see scheme). © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Loading Beijing FLUOBON Surfactant Institute collaborators
Loading Beijing FLUOBON Surfactant Institute collaborators