Strong synergistic effect of cationic hydrocarbon surfactant and novel nonionic tri-block short-chain fluorocarbon surfactant mixtures on surface activity, wettability and solubilization

Mixing hydrocarbon surfactants with fluorocarbon surfactants is still an important strategy to improve the economic benefits and performances of fluorocarbon surfactants and expand their range of application. Herein, we prepared a novel kind of hydrocarbon-fluorocarbon surfactant mixtures via mixing a cationic surfactant, cetyltrimethylammonium bromide (CTAB), with a tri-block nonionic short-chain fluorocarbon surfactant (F9EG13F9) in aqueous solution. The results showed that adding a small CTAB amount to F9EG13F9 (the molar fraction of CTAB in the mixture (x1) was 0.2) could greatly reduce its critical micelle concentrations (cmc) from 0.408 mmol/L to 0.191 mmol/L. At this x1, the contact angle of the mixture was the minimum (57.7 °) at 100 s on polytetrafluoroethylene film, which was even lower than that of F9EG13F9. Besides, CTAB/F9EG13F9 mixtures possessed better colloidal stability and solubilization ability toward hydrophobic dye (Sudan І) than F9EG13F9. The outstanding performances of binary surfactant mixtures benefited from the non-ideal mixing and strong synergistic effect evidence that CTAB/F9EG13F9 surfactant mixtures could be used in practical applications instead of individual F9EG13F9, thereby reducing the used cost of F9EG13F9. Graphical abstract

Study of the Influence of Uniaxial Strain and Electron Irradiation on the Deformation of Polytetrafluoroethylene Film

Experimental studies of the dependence of the deformation ε1max on the strain σ and the relative changes in the width and thickness of the unirradiated and irradiated polytetrafluoroethylene film on the relative elongation are carried out. It was found that these quantities depend essentially on the load. The curves obtained are satisfactorily described by a linear model.

Deployment Finesse of the Gore Excluder Stent Graft

The Gore Excluder stent graft was approved for use in the United States by the US Food and Drug Administration (FDA) in 2002. The Excluder is a modular, bifurcated endoprosthesis utilized in the treatment of abdominal aortic aneurysms. The Excluder endoprosthesis is constructed from an expanded polytetrafluoroethylene film and an incorporated “weldless” nickel–titanium stent skeleton for support. The device features no sutures, infrarenal fixation, and is made to be inserted through 12–18 Fr introducer sheaths. Since its approval by the FDA, the Excluder has undergone multiple changes, including profile reductions, the addition of an impermeable membrane (due to early graft material design associated with type IV endoleaks), and, most notably, a repositioning mechanism labeled the C3 Excluder. This chapter discusses multiple techniques of deployment of the Gore Excluder stent graft.