Corrosion protection properties of tetraphenylethylene-based inhibitors toward carbon steel in acidic medium.

Four novel corrosion inhibitors (1, 2, 3 and 4) integrating different tetraphenylethylene (TPE) cations and thiocyanate (SCN) anions were developed. Weight-loss and electrochemical measurements were employed to assess their protective properties toward carbon steel in 0.5 M HSO, revealing them as effective corrosion inhibitors in the order of 3 > 4 > 2 > 1, with the inhibition efficiencies of 2, 3 and 4 all exceeding 97%.

Interactions of Phospholipid Vesicles with Cationic and Anionic Oligomeric Surfactants.

This work studied the interactions of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) with cationic ammonium surfactants and anionic sulfate or sulfonate surfactants of different oligomeric degrees, including cationic monomeric DTAB, dimeric CCCBr, and trimeric DDAD as well as anionic monomeric SDS, dimeric CCC(SO), and trimeric TED-(CSONa). The partition coefficient P of these surfactants between the DOPC vesicles and water was determined with isothermal titration microcalorimetry (ITC) by titrating concentrated DOPC solution into the monomer solution of these surfactants. It was found that the P value increases with the increase of the surfactant oligomeric degree.

DNA Condensation Induced by a Star-Shaped Hexameric Cationic Surfactant.

The interactions between a star-shaped hexameric cationic quaternary ammonium surfactant PAHB and calf thymus DNA and induced DNA condensation were investigated by ζ-potential, dynamic light scattering, atomic force microscopy, isothermal titration calorimetry, ethidium bromide exclusion assay, circular dichroism, and cytotoxicity assay. With the addition of PAHB, long extended DNA molecules exhibit successive conformational transitions from elongated coil to a partially condensed cluster-like aggregate, to a globules-on-a-string structure, and then to a fully condensed globule until the saturation point of interaction between PAHB and DNA, which is slightly above their charge neutralization point. The efficient condensation is mainly produced by the strong attractive electrostatic interaction between the multiple positively charged headgroups of PAHB and negatively charged phosphate groups of DNA, and the hydrophobic interaction among the multiple alkyl chains of PAHB.

Interactions of Cationic/Anionic Mixed Surfactant Aggregates with Phospholipid Vesicles and Their Skin Penetration Ability.

This work studied the interactions of an oppositely charged surfactant mixture of oleyl bis(2-hydroxyethyl)methyl ammonium bromide (OHAB) and sodium dodecyl sulfate (SDS) with 1,2-di-(9Z-octadecenoyl)-sn-glycero-3-phosphocholine (DOPC) vesicles as well as the penetration of the OHAB/SDS mixture through model skin, aimed at understanding the relationship between the ability of different surfactant aggregates in solubilizing phospholipid vesicles and their potential in irritating skin. By changing the molar fraction of OHAB (X), five kinds of aggregates are constructed: OHAB and SDS separately form cationic and anionic small micelles, whereas the OHAB/SDS mixtures form cationic and anionic vesicles at X = 0.30 and 0.

Transitions in the Molecular Configuration and Aggregates for Mixtures of a Star-Shaped Hexameric Cationic Surfactant and a Monomeric Anionic Surfactant.

A hexameric cationic ammonium surfactant (PAHB), in which six amphiphilic moieties were connected by a star-shaped spacer group, adopted star-shaped, claw-like, and pyramid-like molecular configurations in aqueous solution, depending on the concentration. Herein, we studied the effect of adding sodium dodecyl sulfate (SDS) on the configuration and aggregation behavior of PAHB. Taking these three configurations of PAHB as initial states, the addition of SDS caused transitions of the star-shaped and claw-like configurations into a pyramid-like configuration, whilst the pyramid-like configuration remained unchanged.

Selective Antimicrobial Activities and Action Mechanism of Micelles Self-Assembled by Cationic Oligomeric Surfactants.

This work reports that cationic micelles formed by cationic trimeric, tetrameric, and hexameric surfactants bearing amide moieties in spacers can efficiently kill Gram-negative E. coli with a very low minimum inhibitory concentration (1.70-0.

Aggregation behavior of a gemini surfactant with a tripeptide spacer.

A peptide gemini surfactant, 12-G(NH2)LG(NH2)-12, has been constructed with two dodecyl chains separately attached to the two terminals of a glutamic acid-lysine-glutamic acid peptide and the aggregation behavior of the surfactant was studied in aqueous solution. The 12-G(NH2)LG(NH2)-12 molecules form fiber-like precipitates around pH 7.0, and the precipitation range is widened on increasing the concentration.