Synthesis and Properties of Novel Cationic Maleic Diester Polymerizable Surfactants

The surfactants used in the emulsion polymerization can be thereafter the source of many problems for the application, such as adhesives and coatings. To overcome these negative aspects essentially related to their mobility in the final polymer, surfactants can be covalently linked to the particle surface through incorporation into the polymer chains. Recent years, polymerizable surfactants (surface active monomer or surfmer) are widely reported and used in the emulsion polymerization, many po…     

Synthesis and Surface Activity of Novel Triazole—based Cationic Gemini Surfactants

Gemini surfactants, which contain two hydrophilic groups and two hydrophobic groups in the molecule, are considered as a new generation of surfactants. These surfactants are about 3 orders of magnitude more efficient at reducing surface tension and more than 2 orders of magnitude more efficient at forming micelles than conventional surfactants1. During recent years, many gemini surfactants have been synthesized, and a considerable number of investigations have been reported on their unusua…     

Adsorption and Micellization Properties of Novel Heterodouble‐Chained N‐Acyltaurate Surfactants

A set of heterodouble‐chained N‐acyltaurate surfactants (abbreviated as m+nP‐T, where m and n were carbon numbers of alkyl chain; P was phenyl; T was taurate) were synthesized. The novel amphiphiles contained sodium taurine as hydrophilic moiety and two different hydrocarbon chains as hydrophobic moiety. One was a long alkyl chain, and the other had an aromatic residue. Their surface properties were determined by Wilhelmy‐plate method, and micellization properties were investigated by fluorescence spectra of extrinsic probe and intrinsic probe. It was found that these surfactants showed some aberrant properties. It was difficult to obtain the equilibrium surface tension and critical micelle concentration (cmc) for the surfactants with two long chains. Pyrene was solubilized in micelle at concentration above cmc, and the fluorescent intensity ratio of the first vibronic peak (373 nm) to the third vibronic peak (383 nm) of pyrene decreased gradually. The aggregation number N, characterized by quenching the phenoxyl residue with methyl viologen (MV²⁺) as the extrinsic quencher, gradually increased with increasing surfactant concentration. These indicated that more and more molecules packed in a micelle with increasing concentration.     

Synthesis and Properties of Gemini Cationic Surfactants with Amide Spacers

Four gemini cationic surfactants {N,N‘-di[2-(lauryldimethylamino)acetyl]polymethylenediamine dichloride, LAA-s-LAA, s = 2,3,4,6 } were synthesized by using four bis (a-chloroacetamide)s and N, N-dimethyl-laurylamine, respectively. The molecular structures were characterized by means of IR, ^1H NMR. ^13C NMR and MS, and the behavior of their aqueous solutions was studied. The critical micell concentrations (CMC) of LAA-s-LAA were one order of magnitude lower than that of dodecyltrimethyl ammonium chloride (DTAC). With the change of the length of spacer chain(s), their CMC values change, and CMC reaches the top value at s=4.     

Study of Liquid‐Crystalline Phase Changes during Evaporation in Vegetable Oil Emulsions

During evaporation, the rate between volatile and nonvolatile components in an emulsion changes. In this study, emulsions of marigold and canola oil were made according to a phase diagram, simulating the decreasing water amount that happens when the water evaporates from an emulsion. In addition, two basic emulsions were submitted to evaporation and then to microscopic analysis to compare the results of both tests. It was observed that when the water rate decreases, the liquid‐crystalline phase changes its organization, reaching a proportion that it is not hydrated anymore, having a solid aspect. Moreover, these emulsions submitted to evaporation remained to show lamellar phase even when there was no water in the formulation. This is interesting to understand the behavior of an emulsion after it is applied under the skin.     

Effect of Polycondensation Reaction Conditions on the Properties of Thermotropic Liquid‐Crystalline Copolyester

In this study a range of wholly aromatic copolyesters based on kink m‐acetoxybenzoic acid (m‐ABA) monomer (33 mol%) and equimolar‐linear p‐acetoxybenzoic acid (p‐ABA), hydroquinone diacetate (HQDA) and terephthalic acid (TPA) monomers (67 mol%) have been synthesized by melt polycondensation reaction process at 280°C and 260°C for different time intervals. Characterization of copolyesters were performed by solution viscosity measurement, wide–angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), hot‐stage polarized light microscopy, proton‐nuclear magnetic resonance analysis (¹H‐NMR). According to the results obtained, copolyesters showed thermotropic liquid crystalline behavior in an appropriate temperature range. The copolyesters were prepared in high yields. It was observed that the intrinsic viscosities of the copolyesters are increased regularly with increasing polymerization time and temperature. All the copolyesters were soluble in a trifluoroacetic acid/dichloromethane (30:70 v/v) except the copolyesters which were synthesized at 280°C in 5 h. According to the WAXD results; the degree of crystallinity of copolyesters were found to be between 5–15%. DSC and hot stage polarized light microscopy results showed that all the copolyesters are melt processable and a significant molecular interaction exist in a very broad temperature range (160°C and 165°C) in the nematic mesophase. The T_g values are increased with an increasing polycondensation reaction time and temperature and they were observed between 93–126°C. Fibers prepared by a hand‐spinning technique from the polymer melt exhibit well‐developed fibrillar structure parallel to the fiber axis.     

Synthesis and Characterization of H‐bonded Side‐Chain Liquid‐Crystalline Polysiloxanes

Smectic Liquid‐crystalline (LC) polysiloxanes P1～P7 were prepared using cholesteryl 6‐undec‐10‐enoyloxy‐naphthalene‐2‐carboxylate and cholesteryl 3‐sulfo‐4‐undec‐10‐enoyloxy‐benzoate in a one‐step reaction with sulfonic acid group contents ranging between 0 and wt 4.39%. With an increase of sulfonic acid groups, the glass transition temperature rose slightly; while the temperature of clear point decreased. As sulfonic groups increased, H‐bonding interaction strengthened, resulting in an increase of glass transition temperature. On the other hand, aggregates of H‐bond derived from sulfonic acids would destroy the homogeneous rigid moieties and the high‐ordered structure, resulting in a temperature of clear point decreased. In X‐ray measurement, all the polymers displayed sharp strong peaks around 2θ≈2.6° and broad peaks around 2θ ≈16.6°. The broad peaks at wide‐angle are similar, but there is great different at low angles. For the polymer without sulfonic acid, the only one strong peak at low angle indicates high‐ordered lamellar structure due to homogeneous rigid moieties. For the polymers containing more sulfonic acid, two sharp peaks appeared at low angles, and the intensities of these two peaks varied. With increase of sulfonic acid groups in the polymer systems, the hydrogen‐bonding aggregates in domains would divide the homogeneous rigid mesogens into two kinds of nanophases, that is, one containing non H‐bond mesogens and another involving H‐bonding aggregated mesogens. These two different nanophases result in different lamellar spacings.     

Surface and Antimicrobial Properties of N-Palmitoyl Amino Acid–Based Surfactants

Synthesized sodium N-pamitoyl amino acids were evaluated for surface and antimicrobial properties and compared with sodium lauryl sulfate (SLS). Emulsion stability of the amino acid surfactants and calcium tolerance of the sodium N-palmitoyl isoleucine were better as compared to SLS. Wetting ability and foaming properties of the palmitic acid-based surfactants were inferior to SLS. N-Acyl amino acids exhibited better antibacterial activity compared to sodium salts of N-acyl amino acids and standard compounds against Staphylococcus aureus MLS-16 and Bacillus subtilis. These studies revealed that the palmitoyl amino acid surfactants can be exploited in household, skin care formulations, and industrial applications.     

Synthesis and Properties of Surfactants derived from N‐Acetyl‐D‐Glucosamine

The synthesis of 2‐acetamido‐2‐deoxy‐6‐O‐octanoyl‐D‐glucono‐1,5‐lactone 9 and 2‐acetamido‐2‐deoxy‐6‐O‐octanoyl‐α‐D‐glucopyranose 7 from 2‐acetamido‐2‐deoxy‐α‐D‐glucopyranose is reported. For both targets, the key intermediate was allyl 2‐acetamido‐3,4‐di‐O‐benzyl‐2‐deoxy‐6‐O‐octanoyl‐α‐D‐glucopyranoside 5. Surface tension measurements (critical micellar concentration of 22.3 mM and 5 mM for 9 and 7, respectively) showed up the surface activity of both compounds, while enzyme inhibition assays indicated that 9 could inhibit bovine β‐N‐acetylglucosaminidase (K_i=6.5 µM) but not Serratia marcescens chitobiase nor hen egg‐white lysozyme. Moreover, 7 was shown to induce chitinase production of S. marcescens and to be readily metabolized by these bacteria.      

Synthesis,Structures, and Properties of Novel N‐Aryl‐phenanthren‐o‐iminoquinones

The interaction of 9,10‐phenanthrenquinone with primary amines has been studied. Use of sterically hindered anilines gave the phenanthren‐o‐iminoquinones in good yields. These compounds are structural analogues of o‐benzoquinones. Using single‐electron reduction, o‐iminoquinones may synthesize metal's free‐radical complexes.     

Synthesis and Properties of Aromatic Side Chained N‐Acyltaurate Surfactants

A series of anionic N‐acyltaurate surfactants, side chain containing aromatic nucleus (abbreviated as SAATT), were synthesized via Williamson reaction, hydrolyzation, and acylation. Krafft temperatures and surface properties of these surfactants at 30°C, that is, critical micelle concentration, cmc, surface excess concentration, Γ_max, surface area demand per molecule, A _min, efficiency in surface tension reduction, pC₂₀, effectiveness in surface tension reduction, π_cmc, and cmc/C₂₀ parameter were determined. It was shown that these surfactants exhibit good solubility which was confirmed by measuring Krafft temperature. The cmc of SAATT was much smaller than that of conventional surfactants with similar effective carbon numbers, and shifted to lower concentration with increasing hydrocarbon chain length. In addition, the γ_cmc decreased with decrease in Γ_max. The pC₂₀ and the cmc/C₂₀ got larger with the increase in hydrocarbon chain length. From the fluorescence intensity ratios of I ₁ (373 nm) and I ₃ (384 nm) using pyrene as a probe, it was indicated that the molecules of SAATT formed loose micelles with a broad size distribution.     

Antibacterial and Antifungal Activities—Surface Active Properties Relation of Novel Dischiff Base Cationic Gemini Amphiphiles Bearing Homogeneous Hydrophobes

A novel series of cationic Gemini amphiphiles containing Dischiff base species were synthesized and their chemical structures were determined using different analytical tools. Their surface properties were determined using surface tension measurements. The adsorption and micellization thermodynamic parameters were calculated using Gibb's equations at 25°C. The surface parameters were also determined including critical micelle concentration, effectiveness, efficiency, maximum surface excess, minimum surface area, interfacial tension, and emulsification power. The synthesized cationic Gemini surfactants were evaluated as bactericides for gram negative and gram positive bacteria and also against sulfur reducing bacteria (SRB). The results of the cytotoxicity of the synthesized compounds against the targeted bacterial strains were promising and completely dependent on the surface activity of these compounds.     

Synthesis and Characterization of A Novel Cholesteric Liquid Crystalline Containing Carboxyl Group

A novel liquid crystal compound with a carboxyl group at one end, cholest-5-en-3-ol-(3β) hydrogen decanedioate (1) was successfuly prepared by the reaction of cholesterol with sebacoxl chloride. Its chemical structure and liquid crystalline properties were characterized by FTIR.CNMR,HNMR,POM and DSC. The compound with an active carboxyl group shows themortropic liquid crystalline behaviour.     

Microstructures of Aqueous Two‐Phase Systems Formed by Mixture of Polymer and Cationic‐Anionic Surfactants

Microstructure and phase behavior of decyltriethylammonium bromide (C₁₀NE)/sodium decylsulfonate (C₁₀SO₃)/poly(ethylene oxide) (PEO)/water quaternary systems were studied by freeze‐fracture transmission electron microscopy, small angle X‐ray diffraction, and dynamic light scattering methods. Aqueous two‐phase systems (ATPS) could be prepared by properly mixing the aqueous solution of PEO and equimolar mixed C₁₀NE and C₁₀SO₃. It was shown that the top phase of the ATPS was surfactant‐enriched and mainly composed of multi‐lamellar structure, while the bottom phase of the ATPS was polymer‐enriched in which some vesicles were observed.     

Synthesis of Some Novel Nonionic Ethoxylated Surfactants Based on α-Amino Acids and Investigation of Their Surface Active Properties

Eight novel ethoxylated nonionic surfactants were prepared based on oil soluble α-amino acids. The L-phenylalanine and L-leucine were esterified and amidated with cetyl alcohol and palamitic acid, respectively; two amides and two esters of α-amino acids were obtained. The ethylene oxide was condensed with the prepared amides and esters to get three different polyethylene oxide units (40, 60, and 100) as phenylalanine derivatives. The amide and ester of α-L-leucine were ethoxylated at (60 ethylene oxides units). The analytical micro analysise, FTIR, ¹H NMR, ¹³C NMR, mass spectra were carried out to confirm the chemical structures. The surface tension of the water soluble prepared compounds was measured at 25°C, further the surface active properties were determined and calculated. Such that critical micelle concentration (CMC), surface excess (Γ_max); area per molecule (A_min), effectiveness (γ_CMC) free energy of micellization and adsorption (ΔG_mic, ΔG_ad). From the data obtained it was found that the CMC of phenylalanine esters is greater than that obtained for the amide derivatives. The Γ_max decreased as the ethylene oxide units (EO) increased. It was found also that the ΔG_ad was greater than the ΔG_mic. The obtained data and discrepancy were discussed on the light of surfactant chemical structure.     

Synthesis and Liquid Crystalline Properties of 3-Substituted Pentane-2,4-dione, Pyrazole and Isoxazole Derivatives

The γ-substituted β-diketonate 2,4-dioxo-3-pentyl 4-[4-（n-octyloxy）cinnamoyl]oxybenzoate 1 and its pyrazole and isoxazole derivatives （2 and 3 respectively） have been synthesized and characterized by the spectroscopic methods and elemental analysis. The mesogenic properties of these compounds have been studied by polarizing optical microscopy （POM） and differential scanning calorimetry （DSC）. A monotropic nematic mesophase was observed for the β-diketonate 1, in contrast, the pyrazole 2 displays an enantiotropic smectic A and isoxazole 3 exhibits an enantiotropic nematic mesophase. The relationship between the structure and liquid crystalline properties has also been discussed.     

Effect of Cationic and Zwitterionic Surfactants on Contact Angle of Quartz–Water–Crude Oil System

The influences of four cationic surfactants hexadecyl glycidyl ether ammonium chloride and four zwitterionic surfactants hexadecyl glycidyl ether glycine Betaine solutions on contact angle of crude oil on a quartz surface were investigated using a captive drop method. The effects of surfactant type, structure, and concentration on contact angle were expounded. From obtained results it appears that the adsorbed surfactant at oil–water interface reduces the interfacial tension and the adsorption at quartz–water interface improves interfacial free energy, which results in reducing the stable value of contact angle and weakening dynamic behavior. At high concentration, the zwitterionic surfactant with branched-chain may form semi-micelle at quartz surface. As a result, the stable value of contact angle passes through a sharp minimum with the increasing concentration.     

Synthesis and Characterization of a Novel Liquid Crystalline Chitin — Quaternary Ammonium Chitosan Salt

N-Butyl chitosan(NBCS) derivatives were prepared by introducing butyl groups into the amine groups of chitosan via Schiff base intermediates. The quaternization of NBCS was carried out by using ethyl iodide to produce water-soluble cationic polyelectrolytes. The degree of the substitution of the products was measured by means of the electron spectroscopy for a successful chemical analysis. The quaternary ammonium chitosan salt(QACS) was proved to be a novel cholesteric liquid crystalline chitin, by means of the polarized optical microscopy and the circular dichroism spectropolarimetry. The critical mass fraction of the QACS/formic acid solution forming a lyotropic liquid crystal phase was 50%, which was almost the same as that of the NBCS/formic acid solution, but much hiuher than that of the chitosan in the same solvent.     

Interfacial and Thermodynamic Properties of Formation of Water‐in‐Oil Microemulsions with Surfactants (SDS and CTAB) and Cosurfactants (n‐Alkanols C5–C9)

The interfacial and thermodynamic properties of water‐in‐oil microemulsion systems consisting of water, isopropyl myristate, n‐alkanol, and surfactant have been investigated using the method of dilution. The surfactants used were hexadecyl trimethylammonium bromide and sodium dodecylsulfate, and the cosurfactants were n‐alkanols with varying chain length from (C₅–C₉). The distribution of cosurfactant (n‐alkanol) between the interface of water and oil regions at the threshold level of stability as well as the energetics of the transfer of the cosurfactant from the oil to the interfacial region have been examined as a function of varying cosurfactant chain length (C₄–C₉) and temperature. The structural parameters (including dimension, population density and effective water pool radius) of the dispersed water droplets in the oil phase have also been evaluated and correlated with alkanol chain length.     

Novel,Water‐Based Procedure for the Mono Iodination of Aromatic Amines and Phenols

A mixture of potassium chlorate and potassium iodide was found to be a good iodinating agent for various aromatic amines and phenols with excellent yields in the presence of mineral acid in aqueous medium.