Jan Chlebicki

Surface-active, micellar, and antielectrostatic properties of bis-ammonium salts.

A series of new cationic surfactants, bis-quaternary ammonium dibromides, were synthesized. The properties of these surfactants were characterized by surface tension measurements, conductivity study, and dynamic light scattering. The surface properties, such as surface excess concentration, Gamma(cmc), surface area demand per molecule, A(min), efficiency in surface tension reduction, pC(20), the effectiveness of surface tension reduction, gamma(min), critical micelle concentration, cmc, and standard free energy of micellization, DeltaG(mic)(0) and DeltaG(ads)(0), were obtained by means of surface tension measurements. The antielectrostatic properties were investigated by measuring the surface resistance, the half-charge decay time, and the maximum voltage induced on polyethylene films and propylene unwoven fabrics. Critical micellar concentrations (cmc) of investigated salts were much lower than those of the monomeric salt DTAC. The results obtained in this work were compared to analogous bis-quaternary ammonium dichlorides and well-known gemini cationic surfactants. It was found that the type of counterion had an impact on the values of the micelle ionization degree and the hydrodynamic diameters. Larger aggregates were found for bis-quaternary ammonium dibromides, which had smaller values of the ionization micelle degree than bis-quaternary ammonium dichlorides. Moreover, the antielectrostatic effect strongly depended on the kind of counterion. All investigated salts had very good antistatic properties.

The effect of polyoxypropylene chain length on the critical micelle concentration of propylene oxide—ethylene oxide block copolymers

Abstract “RPE” block copolymer surfactants obtained by the addition of ethylene oxide to n-hexyl and n-heptyl ethers of mono- to tetrapropylene glycol are described. The critical micelle concentration of the copolymers in aqueous solution were determined by surface tension and dye absorption method. A linear decrease of log [CMC] vs number of propylene oxide units in copolymer molecule was observed. The change of work of cohesion per oxypropylene group when it passes from molecular into micellar state, calculated from the Shinoda equation ( Shinoda, K., Nakagawa, T., Tamamushi, B., and Isemura, T., “Colloidal Surfactants.” Academic Press, 1963 ), was 0.43 and 0.42kT for n-hexyl and n-heptyl derivatives, respectively.

Adsorption of n-alkylthiooligooxypropylene glycols at aqueous solution-air interface

Abstract Surface active n -alkylthiooligooxypropylene glycols C n H 2 n +1 SCH 2 CH(CH 3 )- (OCH 2 CH (CH 3 )) z OH n =4, 6, 8; z =0–5 where synthesized and equilibrium surface tension-concentration isotherms of aqueous solutions of these individual substances at 293 K were determined. A new empirical equation dealing with the adsorption process of a whole group of non-ionic surface active substances at the aqueous solution-air interface has been applied to the compounds studied. It has been found that the thiopropylene group, -SCH 2 CH(CH 3 )-, is hydrophobic. The standard free energy contribution, Δ G ° π [-SCH 2 CH(CH 3 )-], is not constant. The change in its value from −1.02 to −2.02 RT with the change in surface pressure π from 0 to 25 mN m −1 is discussed.

Preparation of polymeric nanoparticles using a new polymerizable surfactant

A novel polymerizable surfactant (so-called surfmer) was synthesized and characterized according to its structure, surface activity and polymerization ability. Polymeric micelles (size of 6 and 130 nm) appeared in the polyreaction initiated by free radicals from VA-044. In the presence of the monomer (i.e., methyl methacrylate) microemulsion systems were formed that in turn were transformed into latex entities (size — 40 nm). Additionally, an emulsion polymerization was performed with the use of n-hexadecane as an oil phase resulting in the production of nanocapsules (size in the range — 165–220 nm). The shape and morphologies of the nanoobjects were confirmed using Atomic Force Microscopy (AFM).

Adsorption of oligooxypropylenated amines at the aqueous solution—air interface: Homologous series of piperidine and morpholine derivatives

The surface tension isotherms for pure oligooxypropylenated piperidine and morpholine at the aqueous solution—air interface were determined and interpreted. The surface excess concentration, Γ, the surface area per molecule, A, and the standard free energy of adsorption, ΔG°, were calculated according to a new empirical adsorption equation. The standard free energy contribution for the oxypropylene group (PO) in morpholine derivatives,ΔG° (PO) = −3.34 kJ mol−1, is substantially lower than that for the PO group located in the piperidine derivatives, i.e. ΔG° (PO)= −3.12 kJ mol−1.

Surface and thermodynamic properties of sulphonium surfactants

Abstract Surface and thermodynamic properties of alkylsulphonium iodides have been determined in aqueous solution and in solutions of sodium chloride of 0.1 and 0.5 M total ionic strength at 20, 30 and 40°C. The critical micelle concentrations, maximum surface excess concentration and minimum area per molecule at the aqueous solution-air interface were evaluated from the surface tension isotherms. The standard thermodynamic parameters of micellization and adsorption were also considered in the systems under study. The incorporation of longer alkyl groups to the tetradecylmethylalkylsulphonium iodide molecule involve more visible changes in surface and thermodynamic parameters than the functionalization process with hydroxy group.

Liquid‐Liquid Extraction of Monoalkylethers of Oxyethyelene‐Oxybutylene Block Copolymers

Abstract Monoalkylethers of oxyethyelene‐oxybutylene block copolymers (RBE) are a potentially new group of non‐ionic surfactants. The aim of this paper was the investigation of the isolation of RBE of different chemical structures from the water matrix by liquid‐liquid extraction. Tensammetric techniques were used for the determination of extracted substances. The extraction coefficients of tested compounds grow in the sequence of solvents: hexane < ethyl acetate < dichlomethane < chloroform, as well as with the increase in the length of the alkyl chain. The presence of the oxyethylene chain in the structure of the molecule causes a significant decrease in the extraction coefficient.