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1.
We have been investigating the factors determining the bioavailability of carotenoids from vegetables. The previous paper
[Rich, G.T., Bailey, A.L., Faulks, R.M., Parker, M.L., Wickham, M.S.J., and Fillery-Travis, A. (2003) Solubilization of Carotenoids
from Carrot Juice and Spinach in Lipid Phases: I. Modeling the Gastric Lumen, Lipids 38, 933–945] modeled the gastric lumen and studied the solubilization pathway of carotenes and lutein from carrot juice and
homogenized spinach to oil. Using the same vegetable preparations, we have extended our investigations to solubilization pathways
potentially available in the duodenum and looked at the ease of solubilization of carotenes and lutein within simplified lipid
micellar and oil phases present within the duodenum during digestion. Micellar solubility of raw spinach carotenoids was low
and was enhanced by freezing, which involved a blanching step. The efficiency of solubilization of carotenoids in glycodeoxycholate
micelles decreased in the order luteincarrot>luteinblanched-frozen spinach>caroteneblanched-frozen spinach>carotenecarrot. Frozen spinach carotenoids were less soluble in simple micelles of taurocholate than of glycodeoxycholate. The results comparing
the solubility of the carotenoids in mixed micelles (bile salt with lecithin) with simple bile salt micelles are explained
by the relative stability of the carotenoid in the organelle compared to that in the micelle. The latter is largely determined
by the polarity of the micelle. Below their critical micelle concentration (CMC), bile salts inhibit transfer of carotenoids
from tissue to a lipid oil phase. Above their CMC, the bile salts that solubilize a carotenoid can provide an additional route
to the oil from the tissue for that carotenoid by virtue of the equilibrium between micellar phases and the interfacial pathway.
Mixed micellar phases inhibit transfer of both carotenoids from the tissue to the oil phase, thereby minimizing this futile
pathway. 相似文献
2.
Jagadish Chandra Roy Md. Nazrul Islam Gazi Aktaruzzaman 《Journal of surfactants and detergents》2014,17(2):231-242
This paper presents the effect of NaCl on the Krafft temperature (T K), surface adsorption and bulk micellization of cetyltrimethylammonium bromide (CTAB) in aqueous solution. The critical micelle concentration (CMC) of CTAB in the presence of NaCl increased and then decreased with increasing temperature. Thus, the CMC–temperature data can be represented by a bell-shaped curve. The micellar dissociation (fraction of counterion binding) and energetic parameters (free energy, enthalpy and entropy changes) of both adsorption and micellization were calculated. The processes were found to be both enthalpy and entropy controlled and appeared to be more and more enthalpy driven with increasing temperature. An enthalpy–entropy compensation rule was observed for both adsorption and micelle formation. The T K of the surfactant decreased significantly in the presence of NaCl, which is a sharp contrast to the usual behavior of the effect of electrolytes on the T K of classical ionic surfactants. The surface excess concentrations decreased with increasing temperature. However, the values were much higher in the presence of NaCl compared to the corresponding values in pure water. The solubilization behavior of a water-insoluble dye, Sudan red B (SRB), in the micellar system was studied by the UV–visible spectrophotometric technique. The molar solubilization ratio in the presence of NaCl was found to be about three times higher than that in pure water, indicating that the solubilization of SRB in the CTAB micelles significantly increases in the presence of NaCl. 相似文献
3.
Surface-Active Properties of Solvent-Extracted <Emphasis Type="Italic">Panax ginseng</Emphasis> Saponin-Based Surfactants
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In this study, saponins were extracted from Panax ginseng root powder. The crude solvent‐extracted saponins containing triterpenoid glycosides and terpenes that were identified by TLC techniques. The critical micelle concentrations (CMC) of the saponins were determined by measuring the change in (a) the UV‐visible spectrum of iodine due to the micelle‐iodine complexation, (b) the absorption intensity of aqueous alpha‐lipoic acid due to the micellar solubilization of the drug, and (c) the surface tension due to the abrupt change in the air/liquid interface saturation by surfactants monomers. The development of new absorption peak due to the micelle‐iodine complexation, enhancement in the absorbance due to the micelle‐solubilized lipoic acid, and displacement of monomer‐micelle equilibrium to micelle formation in higher monomer concentration region are some of the physicochemical properties in which CMC could be determined. We found a CMC of 0.009% w/v. 相似文献
4.
Muzaffar Hussain Najar Oyais Ahmad Chat Aijaz Ahmad Dar Ghulam Mohammad Rather 《Journal of surfactants and detergents》2013,16(6):967-973
Mixed micellization and mixed monolayer formation of two bile salts namely sodium cholate (NaC) and sodium deoxycholate (NaDC), in the presence of sodium chloride (NaCl) and three hydrophobic salts including sodium acetate (NaAc), sodium butanoate (NaBu) and sodium hexanoate (NaHx) in 10 mM phosphate buffer (pH 6.5) at 37 °C were investigated by means of surface tension measurements. The experimental results were utilized to evaluate various parameters like critical micellar concentration (CMC), micellar and monolayer interaction parameter (β and β σ), micellar and monolayer mole fractions (X and Z), activity coefficients of two bile salts in mixed micelles and monolayer (f and f (σ)), surface excess (Γmax) and minimum surface area per molecule of bile salt (A min). Mixed micelles and mixed monolayer were found to show slight non-ideality and both these phenomena have been found to be affected differently in the presence of various additive salts with NaHx showing larger effects. Higher efficiency of NaHx in affecting both phenomena has been attributed to its appreciable hydrophobicity and surface activity, thus showing stronger interactions with bile salt molecules. 相似文献
5.
Muhammad Faizan Nazar Syed Sakhawat Shah Muhammad Arshad Khosa 《Journal of surfactants and detergents》2010,13(4):529-537
The aggregation induced by Alizarin Yellow R (AYR) in the cationic surfactant, cetyltrimethylammonium bromide (CTAB), was
investigated by measuring their UV–visible absorption spectra. Conductance measurements as a function of surfactant concentration
below and above the critical micelle concentration (CMC) were studied. CTAB aggregation takes place at the concentration far
below its normal CMC in the presence of AYR. Both hydrophobic and electrostatic interactions affect the aggregation process
in aqueous solution. The dye effect on the CMC of CTAB was noted by a specific conductivity method as well. AYR–CTAB binding
constant (Ks) and water–micelle partition co-efficient (Kx) were quantified with the help of mathematical models employed to determine the partitioning of organic additives in the
micellar phase. The number of dye molecules per micelle was estimated at particular CTAB concentrations above CMC, during
this study. 相似文献
6.
Noulkamol Arpornpong Ampira Charoensaeng David A. Sabatini Sutha Khaodhiar 《Journal of surfactants and detergents》2010,13(3):305-311
The micellar, adsorption, and adsolubilization properties of a novel ethoxy carboxylate extended surfactant are measured and
compared to an extended sulfate surfactant. The critical micelle concentration (CMC) of the ethoxy carboxylate extended surfactant
is measured to be 0.02 mM while it is 0.07 mM for the extended sulfate surfactant. Adsorption and adsolubilization studies
are carried out on alumina oxide surfaces. The extended sulfate surfactant has a higher maximum adsorption capacity onto the
aluminum than the ethoxy carboxylate extended surfactant (0.47 vs. 0.14 mmol/g, respectively). For adsolubilization, the extended
sulfate surfactant shows a slightly higher phenanthrene adsolubilization compared to the ethoxy carboxylate extended surfactant
(log Kadm of 6.15 vs. 5.71, respectively). In contrast, for solubilization, the ethoxy carboxylate extended surfactant exhibits higher
phenanthrene solubilization capacities than the extended sulfate surfactant (log Kmic of 5.61 vs. 5.42, respectively). Relative to surfactant loss from the solid surface, the ethoxy carboxylate extended surfactant
shows a higher desorption capacity as compared to the extended sulfate surfactant. From these measurements, the ethoxy carboxylate
extended surfactant has better properties for micellar applications (lower CMC, higher Kmic), while the extended sulfate surfactant has better properties for admicellar applications (higher qmax and Kadm values, and less desorption). 相似文献
7.
Spectroscopic study of benzothiophene partitioning in sodium dodecyl sulfate and cetyl trimethyl ammonium bromide micellar media
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Sadia Hanif Muhammad Usman Ajaz Hussain Nasir Rasool Abbas Khan Muhammad Asghar Jamal Abdallah Mohamed Elgorban Usman Ali Rana 《Journal of surfactants and detergents》2016,19(5):1033-1041
8.
Louis P. Jackson Ralph Andrade Ian Pleasent Brian P. Grady 《Journal of surfactants and detergents》2014,17(5):911-917
Aqueous solutions of sodium tetradecanoate (S14C) and sodium dodecanoate (S12C) were used to evaluate complicated precipitation phenomena and to monitor the effects of bulk pH adjustments on surface tension and critical micelle concentrations (CMC) determination from surface tension plots. Limited solubilities of pure sodium n-alkyl carboxylates in solution near the CMC have been reported previously many times. In this study, precipitation encountered with solutions prepared from vender-supplied S12C was eliminated through additional purification. As sodium alkyl carboxylates discussed in the literature are commonly used as received from the manufacture without additional purification, the wide range of reported CMC values as well as precipitation near the CMC for S12C are also likely due to impurities. However, complete solubility for S14C solution concentrations near the reported CMC values was not obtained through additional purification of purchased material. Hence, some CMC values reported in the literature for S14C should be reconsidered, as discontinuities in the slope of surface tension versus concentration plots are likely caused by the formation of a precipitate not micelle aggregation. In addition and in agreement with other studies, solution pH adjustments revealed a minimum surface tension for maximum solubility near the pK a value for S14C. 相似文献
9.
The micellar properties of aqueous binary mixed solutions for two systems consisting of sodium cholate (NaC)-octaoxyethylene
glycol mono n-decyl ether (C10E8) and sodium glycocholate (NaGC)-C10E8 have been studied on the basis of surface tensions, polarity of the micelle interior and the mean aggregation number. Application
of two theoretical treatments, based on regular solution and excess thermodynamic quantities for critical micellar concentration
(CMC) data from surface tension curves of two mixed systems showed that the mole fraction of each bile salt in the mixed micelles
near the CMC is lower than that of the corresponding prepared mole fraction in the mixed solution. The polarity of the interior
suggested that the hydrophobicity of intramicelles increased with the increase of the mole fraction of bile salt in the mixed
solution and that the mixed micelles become dramatically more hydrophobic at a mole fraction of 0.68 for NaGC−C10E8 system and 0.75 for NaC−C10E8 system, respectively. This implies that the micelles become richer in the bile salt molecules and the tendency appears strongly
for NaGC−C10E8 system due to the strong cohesion between the conjugated glycines in the NaGC molecules. The decrease of aggregation number
with the increase of the mole fraction of bile salts shows that the micelles approach those of the single system of each bile
salt. This supports the previously mentioned facts. 相似文献
10.
The mechanisms governing the solubilizing interactions between zwitterionic/anionic mixed surfactant systems at different
molar fractions of the zwitterionic surfactant (Xzwitter) and neutral or electrically charged unilamellar liposomes were investigated. The mixed systems were formed by N-dodecyl-N,N-dimethylbetaine
and sodium dodecyl sulfate in the presence of piperazine-1,4-bis-(2-ethanesulfonic acid) buffer at pH 7.20. Unilamellar liposomes formed by egg phosphatidylcholine, in some cases together
with stearylamine or phosphatidic acid, were used. Solubilization was detected as a decrease in static light-scattering of
liposomes. Two parameters were regarded as corresponding to the effective surfactant/lipid molar ratios (Re) at which the
surfactant system (i) saturated the liposomes, Resat, and (ii) led to a total solubilization of liposomes, Resol. From these parameters the bilayer/aqueous medium surfactant partition coefficients for the saturation (Ksat) and complete bilayer solubilization (Ksol) were determined. When Xzwitter was 0.40, The Re and K parameters showed a maximum, whereas the critical micellar concentration (CMC) of these systems exhibited
a minimum, regardless of the electrical charge of bilayers. Given that the ability of the surfactant systems to saturate or
solubilize liposomes is inversely related to the Resat and Resol parameters, these capacities appear to be directly correlated with the CMC of the mixed systems. The similarity of both Ksat and Ksol (particularly for Xzwitter=0.2–0.8) suggests that a similar partition equilibrium governs both the saturation and the complete solubilization of bilayers,
the free surfactant concentration (Sa,Sb), remaining almost constant with similar values to the CMC for each mixed system studied. 相似文献
11.
Roza Bouchal Abdellah Hamel Peter Hesemann Martin In Bénédicte Prelot Jerzy Zajac 《International journal of molecular sciences》2016,17(2)
Surface activity and micelle formation of alkylguanidinium chlorides containing 10, 12, 14 and 16 carbon atoms in the hydrophobic tail were studied by combining conductivity and surface tension measurements with isothermal titration calorimetry. The purity of the resulting surfactants, their temperatures of Cr→LC and LC→I transitions, as well as their propensity of forming birefringent phases, were assessed based on the results of 1H and 13C NMR, differential scanning calorimetry (DSC), and polarizing microscopy studies. Whenever possible, the resulting values of Krafft temperature (TK), critical micelle concentration (CMC), minimum surface tension above the CMC, chloride counter-ion binding to the micelle, and the standard enthalpy of micelle formation per mole of surfactant (ΔmicH°) were compared to those characterizing alkyltrimethylammonium chlorides or bromides with the same tail lengths. The value of TK ranged between 292 and 314 K and increased strongly with the increase in the chain length of the hydrophobic tail. Micellization was described as both entropy and enthalpy-driven. Based on the direct calorimetry measurements, the general trends in the CMC with the temperature, hydrophobic tail length, and NaCl addition were found to be similar to those of other types of cationic surfactants. The particularly exothermic character of micellization was ascribed to the hydrogen-binding capacity of the guanidinium head-group. 相似文献
12.
Guangtao Chang 《Polymer》2009,50(25):6111-31
A carboxyl-capped PLGA-PEG-PLGA block copolymer (PLGA: poly(d,l-lactic acid-co-glycolic acid), PEG: poly(ethylene glycol)) was synthesized, and its self-assembly and thermogelling behaviors in water were studied at different pH values. While the aqueous solution of the virgin PLGA-PEG-PLGA block copolymer with the composition in this paper did not undergo sol-gel transition, that of the end-capped derivative exhibited four macroscopic states, sol, turbid sol, physical gel, and precipitate, dependent upon temperature and pH. Especially between pH 4.5 and 5.0, a concentrated aqueous system underwent sol-gel-(turbid sol)-precipitate transitions upon increase of temperature. Complex of dissociation constant pKa of weak-acid groups on the micelle surfaces was illustrated. Dynamic light scattering, hydrophobic dye solubilization, transmission electron microscopy, NMR, and potentiometric titration were used to examine the relationship between ionization of the end groups of the polymer chains on the molecular level, micellization of the amphiphilic block copolymers on the supermolecular level, and physical gelation on the macroscopic level. The present research reveals the complex of the multi-scale self-assembly of amphiphilic polymer ionomers in a selective solvent. 相似文献
13.
Polycyclic hydrocarbon and polychlorinated biphenyl solubilization in aqueous solutions of mixed micelles 总被引:1,自引:0,他引:1
To determine the physiochemical behavior of xenobiotic hydrocarbons in simulated intestinal content, we examined the partition of 7,12-dimethylbenzanthracene (DMBA), 3-methyl cholanthrene (MC), benzo(a)pyrene, and a polychlorinated biphenyl compound (PCB, Aroclor 1242) between an emulsified oil phase and a mixed micellar solution. In a mixed lipid-bile salt system, negligible amounts of hydrocarbon were present in aqueous solution below the critical micellar concentration (CMC) of sodium taurocholate. Once the CMC was obtained, the 4 hydrocarbons exhibited nearly identical partitions from the lipid into the micellar system which was enhanced by increased concentrations of bile salt, reduction of triglyceride concentration and the formation of mixed rather than pure bile salt micelles. The partition of DMBA and MC into micelles was optimized by long-chain monounsaturated oleic acid and monooleoylglycerol as compared to their octanoic or linoleic counterparts. Linoleic acid and monolinoleoylglycerol maximized the partition of PCB from the oil into the micellar phase. In a mixed micellar system excluding an oil phase and an excess of DMBA, a molar saturation ratio (mol hydrocarbon:mol bile salt) was calculated by regression analysis to be 0.162. This indicates that more than one molecule of hydrocarbon is solubilized per mixed micelle and that the aqueous solubilization of hydrocarbon may be attributed to true micellar solubilization. 相似文献
14.
Hiroyuki Asano Hiroki Sasamoto Minoru Ueno 《Journal of the American Oil Chemists' Society》1994,71(1):47-52
The saturated amounts of solubilized cholesterol (Cch) in mixed micelles of sodium cholate (NaC) and octaoxy-ethylene glycol monon-decyl ether (C10E8) and of sodium zyme assay at 25, 29, 33 and 37°C. The Cch values in both systems increase with the total surfactant concentration. Because the mixed micelles for both systems tend
to form C10E8-rich micelles near the critical micellar concentration (CMC) of the mixed system, the curves of cholesterol solubility approached
the Cch curve for C10E8 alone near the CMC. The tendency of Cch to decrease in both systems with increasing mole fractions of bile salts resembled that of the mean aggregation number of
micelles. Thermodynamic analyses of cholesterol solubilization showed that the free energy of solubilization, if considered
as the transfer of cholesterol from solid state to micellar environment, increased with increasing mole fraction of bile salt.
The enthalpy of cholesterol solubilization (ΔHS→M) decreased with the mole fraction of bile salts and showed break points around the mole fraction of 0.75 for the NaC−C10E8 system and at 0.60 for the NaDC−C10E8 system, respectively. These phenomena resemble earlier hydrophobicity data for mixed micelles by fluorescence measurements.
Furthermore, Cch values for the NaDC−C10E8 system were larger than those for the NaC−C10E8 system because of the structural differences at the 7α hydroxyl group between NaC and NaDC. This fact was confirmed by thermodynamic
calculations. 相似文献
15.
16.
Elif Berna Olutas Teoman Taskesen Necla Büşra Kartal 《Journal of surfactants and detergents》2020,23(1):153-168
Two double-tailed single-head amino acid-based chiral cationic amphiphilic molecules, l -aspartic acid hydrochloride dihexylester (L-ADHE, C6–C6) and l -aspartic acid hydrochloride dioctylester (L-ADOE, C8–C8), were synthesized. 1H NMR, 13C NMR, and Fourier transform infrared (FT-IR) were used to characterize the structures of the esters. Micellization, surface, and structural properties of L-ADHE and L-ADOE in aqueous solution were studied by means of a number of techniques including conductivity, pH, surface tension, density, zeta potential, and dynamic light scattering (DLS). The critical micelle concentration (CMC) of L-ADHE and L-ADOE were found to be very low compared with those of corresponding single-tailed amino acid-based amphiphilic molecules. The pKa values of L-ADHE and L-ADOE in aqueous solutions were determined via pH measurements, and it was observed that they had acidic properties giving low pKa values. The excellent adsorption behaviors at the air/water interface of L-ADHE and L-ADOE in aqueous medium were obtained, i.e. they efficiently lowered the surface tension of water at CMC down approximately to 24.3 and 23.4 mN m−1, respectively. From the density measurements, the volume change due to the micellization process for L-ADOE was found to be quite high compared to L-ADHE, i.e. about three times more. This result and the data obtained from the DLS revealed that the increase in aggregated structures of L-ADOE may be due to vesicle formation. The dye solubilization study was performed by UV–vis absorption spectroscopy for L-ADHE. Besides, the CMC value of L-ADHE was also successfully determined without using any dye through UV–vis spectroscopy. 相似文献
17.
Salt‐Induced Modulation of the Krafft Temperature and Critical Micelle Concentration of Benzyldimethylhexadecylammonium Chloride
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Md. nazrul Islam Komol Kanta Sharker Khokan Chandra Sarker 《Journal of surfactants and detergents》2015,18(4):651-659
In this work, the effect of some sodium salts on the Krafft temperature (TK) and critical micelle concentration (CMC) of benzyldimethylhexadecylammonium chloride (C16Cl) in aqueous solution has been studied. It was observed that the TK can be modulated to lower and higher values and the CMC can be depressed significantly upon the addition of the electrolytes. More chaotropic Br? and I? raise the TK with an increase of the concentration of the ions. On the other hand, less chaotropic NO3? initially lowers and then raises the TK. Kosmotropic F?, SO42? and CO32? gradually lower the TK with increasing concentration of the electrolytes. The more chaotropic ions form contact ion pairs with the surfactant and decrease the solubility with a consequent increase in the TK. On the other hand, kosmotropic ions, being extensively hydrated in the bulk, remain separated from the surfactant by hydrated layers of water molecules. As a result, a significant electrostatic repulsion exists between the charged headgroups of the surfactant, resulting in a decrease in the TK. The CMC of the surfactant decreases significantly in the presence of these ions. The surface tension at the CMC (γCMC) also decreases in the presence of all the salts except for F?. The electrostatic repulsion between the charged headgroups is significantly reduced because of screening of the surface charge of both micelles and adsorbed monolayers by the associated counterions, resulting in a decrease in both the CMC and γCMC. 相似文献
18.
Jyotsna Lakra Deepti Tikariha Toshikee Yadav Manmohan L. Satnami Kallol K. Ghosh 《Journal of surfactants and detergents》2013,16(6):957-966
Water solubility enhancements of two polycyclic aromatic hydrocarbons i.e., naphthalene (Naph) and anthracene (Anth) in single surfactants system have been measured by UV–VIS-Spectrophotometer. The relationships between solubilizing capacity and their solubilization efficiency towards polycyclic aromatic hydrocarbons (PAH) have been quantified and discussed in terms of the molar solubilization ratio (MSR), the micelle-water partition coefficient (K m) and standard free energy of solubilization (ΔG°s). The micellar and surface properties of some cationic and anionic surfactants have been investigated by conductivity, surface tension and fluorescence measurements at 300 K. Above the CMC, maximum solubilization occurs in cationic surfactants where as the solubilization is least in the presence of anionic surfactants. The negative value of ΔG°s shows spontaneity of the solubilization process. The MSR values are larger in naphthalene than anthracene (Naph > Anth). The present studies provide valuable information for the selection of surfactants for solubilizing water-insoluble compounds. 相似文献
19.
Mixed Micellization Study of Alkyltrimethylammonium and Alkyltriphenylphosphonium Bromides in Aqueous Solution
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Shailesh Padasala Bharatkumar Kanoje Ketan Kuperkar Pratap Bahadur 《Journal of surfactants and detergents》2016,19(2):389-398
Mixed micellization study of cationic surfactants viz. alkyltrimethylammonium bromides (CnTAB) and alkyltriphenylphosphonium bromides (CnTPPB) with similar hydrophobic groups (C12-, C14-, and C16-) was performed using tensiometry and UV–visible light spectrophotometry techniques. Critical micelle concentration (CMC) values of the single and binary surfactant mixtures were obtained from a plot of surface tension versus the logarithm of surfactant concentration (C s). The degree of synergy and various mixed micelle parameters like interaction parameter (β), activity coefficients (f m ) and interfacial parameters like surface pressure (π CMC), packing parameter (P), surface excess concentration (Г max), surface tension at the CMC (γ CMC), and minimum area per molecule (A min) were evaluated using the regular solution theory (RST). Thermodynamic parameters were calculated using several proposed models which suggest the mixed micellar system to be more thermodynamically stable than their respective individual components. In addition, a dye solubilization study was performed using a spectrophotometric method to validate the CMC data obtained from tensiometric method. Conductometric measurements were also carried out for the mixture of C12TAB + C12TPPB only as it showed a more negative β, indicating a higher degree of synergism. 相似文献
20.
A. M. Mankowich 《Journal of the American Oil Chemists' Society》1965,42(3):185-189
Micellar solubilization, an action of the detergency mechanism, is considered from the stand-point of quasi-thermodynamics.
The basis of the approach was suggested by the similarity of micellar solubilization and Freundlich adsorption isotherms.
Free energy change (ΔG), heat of solubilization (ΔH) and change in entropy (ΔS) for the micellar solubilization of Orange
OT are calculated using two-phase theory and the Gibbs-Helmholtz equation. It is postulated that the dye concn in the solution
(monomer) phase is that at the critical micelle concn. The dye concn in the solubilized phase is computed for the dye-penetrated
portion of the micellar volume. Calculated values of ΔG in anionic and nonionic surfactants are of the order of magnitude
of a physical adsorption. The positive ΔH values indicate the process is not an adsorption. The positive ΔS values point to
increased randomness or possibly to decreased energy effects due to iceberg water molecule structure surrounding the hydrophobic
dye molecules. The loss of the water structure around the latter in the solubilization process would result in their acquiring
increased configu-rational entropy. 相似文献