Thin organic films containing carbon nanotubes (CNTs) have received increasing attention in many fields. In this study, a robust thin superhydrophobic film has been created by using layer-by-layer assembly of the carbon nanotubes wrapped by poly(dopamine) (CNT@PDA) and poly(ethyleneimine) (PEI). UV-vis spectroscopy, ellipsometry, and quartz crystal microbalance with dissipation (QCM-D) measurements confirmed that the sequential deposition of PEI and CNT@PDA resulted in a linear growth of the (PEI-CNT@PDA) film. This thin film contained as much as 77 wt% CNTs. Moreover, a very stable and flexible free-standing (PEI-CNT@PDA) film could be obtained by employing cellulose acetate (CA) as a sacrificial layer. The film could even withstand ultrasonication in saturated SDS aqueous solution for 30 min. SEM observations indicated that the ultrathin film consisted of nanoscale interpenetrating networks of entangled CNTs and exhibited a very rough surface morphology. The (PEI-CNT@PDA) film turned superhydrophobic after being coated with a low-surface-energy compound. The superhydrophobic films showed excellent resistance against the adhesion of both platelets and Escherichia coli (E. coli). The (PEI-CNT@PDA) films and the proposed methodology may find applications in the area of medical devices to reduce device-associated thrombosis and infection.
Self-metathesis of fatty acid methyl
esters (FAMEs) from natural
oils and commercial oleic acid was carried out using a microwave reactor
in solvent-free conditions. Self-metathesis products were further
identified and quantified by gas chromatography–mass spectroscopy
(GC–MS) and gas chromatography–flame ionization detector
(GC–FID). Conversion of ∼50% was achieved within a short
span (∼2 min) in the presence of 0.05 mol % Hoveyda–Grubbs
second generation catalyst (HG2) giving an equilibrium
mixture of alkenes, α,ω-diester, and FAMEs. Highly pure
dimethyl-9-octadecene-1,18-dioate (diester) was separated, and the
desired quantity of it was reduced to 9-octadecene-1,18-diol (diol).
Condensation polymerization of diester and diol as monomers was performed
using conventional heating, microwave irradiation, and microwaves
coupled with conventional heating. Characterization and analysis of
synthesized biopolyesters were carried out using different techniques
including nuclear magnetic resonance (NMR), Fourier transform infrared
spectroscopy (FTIR), differential scanning calorimetry (DSC), gel
permeation chromatography (GPC), thermal gravimetric analysis (TGA),
dynamic mechanical analysis (DMA), and tensile tests. Polyesters with
the highest molecular weight of 337 kDa, ∼50 °C melting
point, degradation temperature of about 400 °C, and the maximum
strength of ∼5.5 MPa were obtained. These materials have great
future potential to be used in different applications as a substitute
of nonrenewable polyesters.
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