Conductometric and microcalorimetric analysis of the alkaline-earth/alkali-metal ion exchange onto polyacrylic acid

The specificity of the exchange between divalent (Di²⁺ = Ca²⁺ or Ba²⁺) and monovalent (M⁺ = Li⁺, Na⁺ or K⁺) ions onto a polyacrylic chain is examined using conductometric and microcalorimetric techniques. Assuming the formation of a bidentate complex between the Di²⁺ and the carboxylate groups, the conductometric data give the exchange ratio (Di²⁺/M⁺) and the speciation of the acrylic groups. No significant difference is observed between the three alkali-metal ions for a given Di²⁺ ion. Comparisons between Ca²⁺ and Ba²⁺ show a stronger hydrophobicity of the former as it precipitates at a complexation ratio r = 0.33 versus r = 0.45 for the Ba²⁺ salt. Microcalorimetric data show that all Di²⁺/M⁺ exchange energies are positive and depend significantly on the type of cations. The largest displacement energy (the more positive) is found for the binding of Ca²⁺ with sodium polyacrylate (8.13 kJ · mol⁻¹) and the smallest for Ba²⁺ with lithium polyacrylate (1.88 kJ · mol⁻¹). The interpretation of the data leads to the conclusion that specificity of the Di²⁺ binding originates in the dehydration phenomenon and specificity between the three alkali-metal ions is due to the decrease in the electrostatic bond strength with an increase in the ionic radii. The Di²⁺/M⁺ exchange is entropically driven. Received: 28 January 1999 Accepted in revised form: 7 April 1999     

Influence of metal ions on the alkali-swelling behavior of carboxylated acrylic polymer latexes

The alkalization of carboxylated acrylic polymer latexes by sodium hydroxide gives rise to swelling of the particles. For a poly(n-butyl acrylate) latex copolymerized with 15 wt % methacrylic acid (MAA) and 7 wt % acrylonitrile the particle volume increases by a factor of 30. The alkali-swelling does not depend on the type of monovalent cation used in the base (LiOH, NaOH, KOH, NH₄OH). In contrast, when bivalent cation bases such as Ca(OH)₂ are employed no latex swelling is observed during neutralization because of ionic crosslinking of the copolymer chains. Crosslinking also takes place when the bivalent cations (Ca²⁺, Zn²⁺, Mg²⁺) are added as chlorides to dispersions with latexes previously swollen by sodium hydroxide. In these experiments the original size of the latexes is reached again at a molar ratio MAA: bivalent metal ion of 2:1, i.e. at charge compensation of the carboxyl groups. The shrinking behavior is almost independent of the type of bivalent metal ion used. On the other hand, it is more pronounced when trivalent cations such as Fe³⁺ are added. In general, the experiments demonstrate that the alkali swelling of acrylic latexes is dominated by electrostatic forces. Received: 18 August 1998 Accepted in revised form: 26 October 1998     

Interaction of partially ionized poly(acrylic acid) with a surfactant counterion at constant pH values

Binding of a cationic surfactant ion, dodecylpyridinium ion, to poly(acrylic acids) of low charge densities was examined by potentiometry using surfactant-selective electrodes in the solutions, where the pH was kept constant by employing a pH buffering system. The binding of the surfactant counterions was thus able to be studied at a constant pH during the binding process. The binding took place in two steps, the first cooperative binding step and the second gradual binding step. The critical association concentration decreased as the pH increased, indicating the predominant role of the electric interaction in the binding. The binding isotherms obtained at different but constant pH values were analyzed by the matrix method, taking into account the nearest-neighbor interactions among three different kinds of sites on the polymer: ionized, protonated, and surfactant-bound. The theoretical analysis could describe only the first step but could not explain the second step. A relatively large cooperativity parameter, u, was found for the first step and it can be between 3 × 10³ and 1 × 10⁴. When the ionic strength was decreased tenfold, the cooperativity of the binding decreased (u∼1 × 10³). The binding constants of the isolated site were 5.5–6.0 × 10⁴ kg mol⁻¹ and slightly increased to 6.5 × 10⁴ kg mol⁻¹ as the ionic strength decreased. The deviation of the second step from the theoretical analysis was supposed to arise from a change of proton dissociation constant in the nonpolar space formed by the bound surfactants. Received: 29 November 2000/Accepted: 24 January 2001     

Osmotic coefficients of vinylic polyelectrolyte solutions without added salt

 The osmotic pressures of –polyelectrolyte solutions without added salt was measured in the concentration ranges 0.001–0.02 and 0.2–1.9 mol kg^-1. Our results show that the osmotic coefficients φ_p were strongly dependent on the chemical structures of polyelectrolyte through the polyion radius and the interaction between the ionic moiety and counterions. The osmotic pressures in polyelectrolyte solutions without added salt, calculated on the basis of the counterion contribution, are in agreement with the experimental results. We conclude that the counterion contribution is dominant in the osmotic pressures and thus, the polymer contribution is negligible in the examined concentration range 0.2–1.9 mol kg^-1. The P–B approach gave a fair prediction of the absolute values of the osmotic pressures with λ=4.5, where λ is the charge density parameter, except for NaPA. In other words, the concentration dependence of the φ_p values can be explained in terms of the counterion contribution. Received: 11 June 1997 Accepted: 19 August 1997     

A microchip sensor for calcium determination

A newly designed glass-PDMS microchip-based sensor for use in the determination of Ca²⁺ ions has been developed, utilizing reflectance measurements from arsenazo III (1,8-dihydroxynaphthalene-3,6-disulfonic acid-2,7-bis[(azo-2)-phenyl arsenic acid]) immobilized on the surface of polymer beads. The beads, produced from cross-linked poly(p-chloromethylstyrene) (PCMS), were covalently modified with polyethylenimine (PEI) to which the Arsenazo III could be adsorbed. The maximum amount of Arsenazo III which could be immobilized onto the PEI-attached PCMS beads was found to be 373.71 mg g⁻¹ polymer at pH 1. Once fabricated, the beads were utilized at the detection point of the microfluidic sensor device with a fiber optic assembly for reflectance measurements. Samples were mobilized past the detection point in the sensor where they interact with the immobilized dye. The sensor could be regenerated and re-used by rinsing with HCl solution. The pH, voltage, linear range, and the effect of interfering ions were evaluated for Ca²⁺ determination using this microchip sensor. At the optimum potential, 0.8 kV, and pH 9.0, the linear range of the microchip sensor was 3.57 × 10⁻⁵ – 5.71 × 10⁻⁴ M Ca²⁺, with a limit of detection (LOD) of 2.68 × 10⁻⁵ M. The microchip biosensor was then applied for clinical analysis of calcium ions in serum with good results. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

Enhanced electrochemical properties of polyethylene oxide-based composite solid polymer electrolytes with porous inorganic–organic hybrid polyphosphazene nanotubes as fillers

Solid composite polymer electrolytes consisting of polyethylene oxide (PEO), LiClO₄, and porous inorganic–organic hybrid poly (cyclotriphosphazene-co-4, 4′-sulfonyldiphenol) (PZS) nanotubes were prepared using the solvent casting method. Differential scanning calorimetry and scanning electron microscopy were used to determine the characteristics of the composite polymer electrolytes. The ionic conductivity, lithium ion transference number, and electrochemical stability window can be enhanced after the addition of PZS nanotubes. The electrochemical impedance showed that the conductivity was improved significantly. Maximum ionic conductivity values of 1.5 × 10⁻⁵ S cm⁻¹ at ambient temperature and 7.8 × 10⁻⁴ S cm⁻¹ at 80 °C were obtained with 10 wt.% content of PZS nanotubes, and the lithium ion transference number was 0.35. The good electrochemical properties of the solid-state composite polymer electrolytes suggested that the porous inorganic–organic hybrid polyphosphazene nanotubes had a promising use as fillers in SPEs and the PEO₁₀–LiClO₄–PZS nanotube solid composite polymer electrolyte might be used as a candidate material for lithium polymer batteries.     

Polydisperse fractal aggregate formation in clay mineral and iron oxide suspensions, pH and ionic strength dependence

pH- and ionic-strength-dependent aggregation of permanently and conditionally charged clay mineral (montmorillonite) and iron oxide (magnetite) particles was investigated by means of dynamic light scattering and rheology. An indifferent electrolyte (NaCl) was used. The surface charging of solids was determined by acid–base titration. The point of zero charge (PZC) of magnetite seemed to be at pH 8.0 ± 0.1. The permanent negative charges on the basal plane of montmorillonite influence the interfacial distribution of H⁺ and Na⁺ ions. The pH dependence of the electrophoretic mobility showed directly the dominance of negative charges on montmorillonite lamellae independently of pH, while for magnetite the sign of the mobility reversed at pH ˜ 8.0. Montmorillonite particles formed stable suspensions; coagulation did not take place below 35 mM 1:1 electrolyte independently of pH. The aggregation of magnetite sol becomes significant near the pH of the PZC even at low ionic strength. Colloidal stability in composite systems was investigated at pH ˜ 4, where oxide and clay mineral particles are oppositely charged. At the lowest NaCl concentrations (1, 5 mM) the mixed systems remained stable and aggregation of oppositely charged particles could not be observed at all. Heterocoagulation of dissimilar particles needed a definite amount of dissolved electrolytes (about 8 mM). Mixed clay mineral and oxide systems are more sensitive to electrolyte under acidic conditions than those separately. Rheological investigation of the mixed clay mineral–oxide suspensions at pH ˜ 4 provided proof for the absence of attractive particle interaction at low ionic strength (2 mM). A physical network of oppositely charged particles could form only at higher salt concentration, for example, in the presence of 10 mM NaCl. The yield value of plastic systems showed a significant maximum at 1:15 magnetite/montmorillonite mass ratio. Received: 21 November 2000 Accepted: 20 December 2000     

Impedance study of adsorption of iodide ions at Cd(0001) and Bi(111) electrode from various solutions with constant ionic strength

Adsorption of iodide ions at the Bi(111) and Cd(0001) electrodes from the aqueous solutions with constant ionic strength 0.1x M KI + 0.1(1−x) M KF and 0.1x M KI + 0.033(1−x) M K₂SO₄ has been studied by impedance spectroscopy. It was found that, to a first approximation, the classical Frumkin–Melik–Gaikazyan equivalent circuit with the slow diffusion-like and adsorption steps can be applied for fitting the experimental impedance data for iodide ions adsorption on Bi(111) and Cd(0001) from aqueous solutions with constant ionic strength. The modified Grafov–Damaskin circuit can be used in the region of electrode potentials, where parallel faradic processes (electroreduction of protons, oxygen traces) are probable. The more complicated Ershler equivalent circuit, taking into account the slow diffusion-like, adsorption and charge transfer steps, is not applicable for characterization of the adsorption process of I⁻ at Bi(111) and Cd(0001) electrodes.     

Ca<Superscript>+2</Superscript> Concentrations are Key Determinants of Ischemia–Reperfusion-Induced Apoptosis: Significance for the Molecular Mechanism of Bcl-2 Action

The mechanism of action of the anti-apoptotic oncogene Bcl-2 and Ca⁺² regulation in ischemia–reperfusion injury is still obscure. In this present study, we investigated mitochondrial Ca⁺² overloads and mechanism of action of Bcl-2. Eighteen Wistar rats were divided into sham-operated control group (I) (n = 6), ischemia and reperfusion group (II) (n = 6), and amlodipine-treated group (1 mg kg⁻¹ body weight/daily by oral route for 7 days before inducing ischemia–reperfusion maneuver) (III) (n = 6). Rats were subjected to 1 h of hepatic ischemia followed by 3-h reperfusion. Mitochondrial Ca²⁺ content was determined and damage was confirmed by transmission electron microscopy. Decrease of mitochondrial Ca⁺² level is related to reduction of apoptosis and cellular changes, viz. increased Bcl-2 expression followed by reduction in secondary endoplasmic reticulum, whereas ischemia/reperfusion group shows overloading Ca⁺² ions and decrease in Bcl-2 expression as compared to sham-operated rats. Thus, Bcl-2-dependent reduction of Ca⁺² is an important component of the anti-apoptotic program in ischemia–reperfusion injury.     

The effect of the melting of the collagen-like gelatin aggregates on the stability against aggregation of the bovine casein micelles

The effect of the melting of the collagen-like acid and alkaline gelatin aggregates on the stability against aggregation of bovine casein micelles was investigated by turbidimetry, DSC and circular dichroism in the wide range of biopolymers concentrations, gelatin/casein ratio (R) in initial mixture (R=0.03–20), pH (4.9–6.7), ionic strength (I=10⁻³ to 1.0/NaCl/), and temperature (10°–70 °C), using glucono-δ-lactone (GL) as acidifier. At low ionic strength (10⁻³/milk salts/) and neutral pH interaction between gelatin molecules and casein micelles is suppressed significantly above 36 °C. The melting of the collagen-like acidic gelatin above this temperature shifts the pH at which the complex formation is maximal to the acidic range. The cause may be that some of the functional ionized groups of gelatin molecules are inaccessible due to the conformational changes. The presence of gelatin B molecules had no effect on the aggregation stability of micellar casein in the range 0.03<R<20. At very high total protein concentration (above 10%) depletion flocculation of casein micelles was observed. The reason for the very high stability of casein micelles in this case cannot be explained by volume exclusion. Received: 28 March 2000 Accepted: 5 October 2000     

Magnesium ion-conducting gel polymer electrolytes dispersed with fumed silica for rechargeable magnesium battery application

Effect of fumed silica dispersion on poly(vinylidene fluoride-co-hexafluoropropylene)-based magnesium ion-conducting gel polymer electrolyte has been studied using various physical and electrochemical techniques. The composite gel electrolytes are free-standing and flexible films with enough mechanical strength. The optimized composition with 3 wt.% filler offers a maximum ionic conductivity of ∼1.1 × 10⁻² S cm⁻¹ at ∼25 °C with good thermal and electrochemical stabilities. The Mg²⁺ ion conduction in the gel nanocomposite film is confirmed from the cyclic voltammetry, impedance spectroscopy, and transport number measurements. The space-charge layers formed between filler particles and gel electrolyte are responsible for the enhancement in ionic conductivity. The applicability of the gel nanocomposite to a rechargeable battery is examined by fabricating a prototype cell consisting of Mg [or Mg-multiwalled carbon nanotube (MWCNT) composite] and MoO₃ as negative and positive electrodes, respectively. The discharge capacity and the rechargeability of the cell have been improved when Mg metal is substituted by Mg-MWCNT composite. The discharge capacity of the optimized cell has found to be ∼175 mAh g⁻¹ of MoO₃ for an initial ten charge–discharge cycles.     

Electrostatic interaction between chitosan-modified latex particles and bovine serum albumin

Electrostatic interaction between poly(methyl methacrylate) latex particles with different levels of chitosan modification and bovine serum albumin (BSA) was investigated. The critical flocculation concentration is in the range 5–15 nmol dm⁻³ for these latex products toward added BSA. A series of isothermal equilibrium adsorption experiments shows that the adsorption process is divided into two distinct intervals. Adsorption of BSA on latex particles in intervals I and II is primarily controlled by charge neutralization and hydrophobic interaction, respectively. Intervals I and II can be reasonably described by an empirical parabola equation and the Langmuir isotherm model, respectively. The maximum amount of BSA adsorbed per unit weight of polymer particles was observed at pH ≅ 5. A maximum elution yield of about 80% can be achieved using NaSCN as the elution electrolyte, and NaSCN is more effective in inducing desorption of BSA from the particle surface than NaCl. The chitosan content has very little effect on the interaction between latex particles and BSA. By contrast, the influence of the content of 2,2′-azobis(2-amidinopropane) dihydrochloride, a cationic initiator used in preparing the chitosan-modified latex products, on the BSA adsorption process is significant. Received: 26 March 1999 Accepted in revised form: 3 June 1999     

Impedance studies on the 5-V cathode material,LiCoPO<Subscript>4</Subscript>

Olivine-structured LiCoPO₄ is synthesized by a Pechini-type polymer precursor method. The structure and the morphology of the compounds are studied by the Rietveld-refined X-ray diffraction, scanning electron microscopy, Brunauer, Emmett, and Teller surface area technique, infrared spectroscopy, and Raman spectroscopy techniques, respectively. The ionic conductivity (σ ionic), dielectric, and electric modulus properties of LiCoPO₄ are investigated on sintered pellets by impedance spectroscopy in the temperature range, 27–50 °C. The σ (ionic) values at 27 and 50 °C are 8.8 × 10⁻⁸ and 49 × 10⁻⁸ S cm⁻¹, respectively with an energy of activation (E _a) = 0.43 eV. The electric modulus studies suggest the presence of non-Debye type of relaxation. Preliminary charge–discharge cycling data are presented.     

Molecular orbital study on the OH stretching frequency of the phenol dimer and its cation

Ab initio calculations were performed to investigate the structure and bonding of the phenol dimer and its cation, especially the OH stretching frequencies. Some stable structures of the phenol dimer and its cation were obtained at the Hartree–Fock level and were found to be in agreement with predictions based on spectroscopic investigations. In these dimers the phenol moieties are bound by a single OH⋯O hydrogen bond. The hydrogen bond is much stronger in the dimer cation than in the neutral dimer. The calculated binding energy of the phenol dimer in the most stable structure was 6.5–9.9 kcal/mol at various levels of calculation, compared with the experimental value of 5 kcal/mol or greater. The binding energy of the phenol dimer cation is more than 3 times (24.1–30.6 kcal/mol) as large as that of the neutral dimer. For the phenol dimer the OH stretching frequency of the proton-accepting phenol (PAP) is 3652 cm⁻¹ and that of the proton-donating phenol (PDP) is 3516 cm⁻¹; these are in agreement with observed values of 3654 and 3530 cm⁻¹, respectively. For the phenol dimer cation the OH stretching frequency of the PAP is 3616–3618 cm⁻¹ in comparison with an observed value of 3620 ± 3 cm⁻¹. That of the PDP in the dimer cation is calculated to be 2434–2447 cm⁻¹, which is 1210–1223 cm⁻¹ lower than that of the bare phenol. The large reduction in the OH stretching frequency of the PDP in the phenol dimer cation is attributed to the formation of a stronger hydrogen bond in the cation than in the neutral dimer. Received: 24 March 2000 / Accepted: 26 April 2000 / Published online: 11 September 2000     

Ion-specific swelling behavior of poly(vinyl alcohol) gel prepared by γ-ray irradiation

Poly(vinyl alcohol) gel was prepared by γ-ray irradiation of an aqueous solution of the polymer and its swelling behavior in solutions of the alkali-metal and alkaline-earth-metal salts was investigated. The gel deswelled in solutions containing strongly hydrated anions and swelled in solutions containing strongly hydrated cations. The degree of swelling of the gel was in the following order: SO₄ ²⁻<Cl⁻<Br⁻ ≅ NO₃ ⁻<I⁻ for the anions and K⁺<Na⁺<Li⁺ and Sr²⁺<Ca²⁺<Mg²⁺ for the cations. These results were interpreted in terms of interactions between the polymer and the ions through the hydration layers. Received: 6 November 2000 Accepted: 24 May 2001     

Selective Solid-Phase Extraction of Trace Copper Ions in Aqueous Solution with a Cu(II)-Imprinted Interpenetrating Polymer Network Gel Prepared by Ionic Imprinted Polymer (IIP) Technique

An Cu(II)-imprinted interpenetrating polymer network (IPN) gel of epoxy-diethylenetriamine and methacrylic acid-acrylamide-N,N′-methylene-bis-(acrylamide) was synthesized by the ionic imprint polymer (IIP) technique. The first polymer network is formed by epoxy gelation with diethylenetriamine. The other is formed by copper methacrylate co- polymerization with acrylamide and cross-linker N,N′-methylene-bis-(acrylamide). The adsorption–desorption characteristics of the IPN gel as a highly selective solid-phase extraction (SPE) and preconcentration adsorbent for Cu²⁺ from aqueous solution were investigated. The experimental results show that trace Cu²⁺ ions can be quantitatively enriched at pH 5 with recovery >95%. The maximum static adsorption capacity of the ion-imprinted functionalized gel adsorbent was 76 mg g⁻¹. Comparing with non-imprinted IPN gel, the imprinted IPN gel has higher adsorption capacity and selectivity for Cu²⁺ by the static adsorption–desorption experiment. Simultaneously, the times of adsorption equilibration and complete desorption were remarkably short. The precision (RSD) for 11 replicate adsorbent extractions of 20 ng mL⁻¹ Cu²⁺ was 3.4%. The established procedure was applied to two real water samples with satisfactory results. The prepared ion-imprinted IPN gel adsorbent was shown to be promising for solid-phase extraction coupled with atomic absorption spectrometry (AAS) for the determination of trace copper in real samples. In addition, the coordination interaction of Cu²⁺ and functional groups of the IPN gel adsorbent was primarily discussed by FT-IR spectra.     

Quasirelativistic valence ab initio calculation of the potential-energy curves for Cd–rare gas atom pairs

The results of large-scale valence ab initio calculations of the potential-energy curves for the ground states and several excited states of Cd–rare gas (RG) van der Waals molecules are reported. In the calculations, Cd²⁰⁺ and RG⁸⁺ cores are simulated by energy-consistent pseudopotentials, which also account for scalar-relativistic effects and spin-orbit interaction within the valence shell. The potential energies of the Cd–RG species in the ΛS coupling scheme have been evaluated by means of ab initio complete-active-space multiconfiguration self-consistent-field (CASSCF)/CAS multireference second-order perturbation theory (CASPT2) calculations with a total 28 valence electrons, but the spin-orbit matrix has been computed in a reduced configuration interaction space restricted to the CASSCF level. Finally, the Ω potential curves are obtained by diagonalization of the modified spin-orbit matrix (its diagonal elements before diagonalization substituted by the corresponding CASPT2 eigenenergies). The calculated potential curves, especially the spectroscopic parameters derived for the ground states and several excited states of the Cd–RG species are presented and discussed in the context of available experimental data. The theoretical results exhibit very good agreement with experiment. Received: 20 April 2000 / Accepted: 1 September 2000 / Published online: 21 December 2000     

Recombination of silicon ions by electron capture from atomic hydrogen and helium

 Ab initio potential-energy curves and coupling matrix elements of the Σ and Π molecular states involved in the collision of the Si²⁺, Si³⁺ and Si⁴⁺ multicharged ions on atomic hydrogen and helium have been determined by means of configuration interaction methods. The total and partial electron capture cross sections have been determined using a semiclassical or a quantal approach in the 0.002–0.1 au velocity range. A detailed comparison with very recent theoretical and experimental rate coefficient results is made. Received: 14 September 1999 / Accepted: 3 February 2000 / Published online: 2 May 2000     

Ion chromatographic and spectrometric determination of water-soluble compounds in airborne particulates, and their correlations in an industrial area in Attica, Greece

In the time period from June 2005 to May 2006 in 42 sampling campaigns 84 filter samples of airborne particulate matter, coarse (PM_10–2.5) and fine (PM_2.5), were collected using a Gent stacked filter unit in the coastal industrial area of Aspropyrgos in Attica, Greece. The average PM₁₀ (PM_10–2.5 + PM_2.5) concentration was found to be 66 μg · m⁻³, exceeding more than 1.6 times the annual limit of 40 μg · m⁻³. The samples were analysed for Cl⁻, NO₃ ⁻, SO₄ ²⁻, Ca²⁺, Mg²⁺, Na⁺, K⁺ and NH₄ ⁺ using ion chromatography. The data were compared with results obtained with other spectrometric methods, such as inductively coupled plasma-atomic emission spectrometry, atomic absorption spectrometry, energy dispersive X-ray fluorescence and reflectometry. The determined average ionic content comprised about 44% of the PM₁₀ mass. The ionic composition, as well as the possible matrix compounds in both fractions were evaluated by dividing the sampling period into summer and winter season. In the PM_10–2.5/PM_2.5 fraction in summer time the concentrations of Ca²⁺, Mg₂₊ and NO₃ ⁻ were enriched in the coarse fraction. In winter time all species were enriched in the coarse fraction, especially Ca²⁺, Cl⁻ and NO₃ ⁻. NH₄ ⁺ was constantly higher in the fine fraction in summer as well as in winter time. Factor analysis was applied to obtain correlations between cations and anions leading to matrix compounds in both fractions. From the evaluation of the results obtained, some of the local air pollution sources could be identified. Correspondence: Klaus-Michael Ochsenkühn, Laboratory for Trace Element Studies, Institute of Physical Chemistry, NCSR “Demokritos”, Aghia Paraskevi 15310, Athens, Greece     

Function and performance of silicone copolymer (VI). Synthesis and novel solution behavior of water-soluble polysiloxanes with different hydrophiles

Silicone surfactants containing different pendant hydrophilic groups such as diethanol tertiary amine (SHE, nonionic), diethanol methyl quaternary amine (cationic) and triethyl quaternary amine (cationic) have been synthesized and characterized by ¹H and ¹³C NMR and gel permeation chromatography. The solution behavior of these novel surfactants has also been investigated by surface tension measurement and a fluorescence method. It has been observed that the surface tension of these surfactants decreases as a function of time at a very low polymer concentration (1 × 10⁻⁴ wt%). At higher concentration (0.1 wt%), the equilibrium surface tensions reached very low values compared to that of typical polymer surfactants, for example, poly(ethylene oxide–propylene oxide) block copolymer (EPE0.8). In addition, the low I ₁/I ₃ values of these silicone surfactants indicate the formation of polymer aggregates in aqueous solution, and an extremely low I ₁/I ₃ value of SHE (1.06) compared to other polymeric surfactants (EPE0.8) and conventional surfactants [poly(ethylene glycol n-nonyl phenyl ethers), cetyltrimethylammonium bromide, and sodium dodecyl sulfate] indicates its stronger hydrophobicity. Received: 15 May 2000 Accepted: 18 October 2000