Superhydrophobic Copper Surfaces with Anticorrosion Properties Fabricated by Solventless CVD Methods

Due to continuous miniaturization and increasing number of electrical components in electronics, copper interconnections have become critical for the design of 3D integrated circuits. However, corrosion attack on the copper metal can affect the electronic performance of the material. Superhydrophobic coatings are a commonly used strategy to prevent this undesired effect. In this work, a solventless two-steps process was developed to fabricate superhydrophobic copper surfaces using chemical vapor deposition (CVD) methods. The superhydrophobic state was achieved through the design of a hierarchical structure, combining micro-/nanoscale domains. In the first step, O₂- and Ar-plasma etchings were performed on the copper substrate to generate microroughness. Afterward, a conformal copolymer, 1<i>H</i>,1<i>H</i>,2<i>H</i>,2<i>H</i>-perfluorodecyl acrylate–ethylene glycol diacrylate [p­(PFDA-<i>co</i>-EGDA)], was deposited on top of the metal via initiated CVD (iCVD) to lower the surface energy of the surface. The copolymer topography exhibited a very characteristic and unique nanoworm-like structure. The combination of the nanofeatures of the polymer with the microroughness of the copper led to achievement of the superhydrophobic state. AFM, SEM, and XPS were used to characterize the evolution in topography and chemical composition during the CVD processes. The modified copper showed water contact angles as high as 163° and hysteresis as low as 1°. The coating withstood exposure to aggressive media for extended periods of time. Tafel analysis was used to compare the corrosion rates between bare and modified copper. Results indicated that iCVD-coated copper corrodes 3 orders of magnitude slower than untreated copper. The surface modification process yielded repeatable and robust superhydrophobic coatings with remarkable anticorrosion properties

Stable 5,5′-Substituted 2,2′-Bipyrroles: Building Blocks for Macrocyclic and Materials Chemistry

The preparation and characterization of a family of stable 2,2′-bipyrroles substituted at positions 5 and 5′ with thienyl, phenyl, TMS-ethynyl, and vinyl groups is reported herein. The synthesis of these new bipyrroles comprises three steps: formation of the corresponding 5,5′-unsubstituted bipyrrole, bromination, and Stille or Suzuki coupling. The best results in the coupling are obtained using the Stille reaction under microwave irradiation. The new compounds have been fully characterized by UV–vis absorption, fluorescence, and IR spectroscopies and cyclic voltammetry. X-ray single-crystal analysis of four of the synthesized bipyrroles indicates a trans coplanar geometry of the pyrrole rings. Furthermore, the substituents at positions 5,5′ remain coplanar to the central rings. This particular geometry extends the π-conjugation of the systems, which is in agreement with a red-shifting observed for the λ_max of the substituted molecules compared to the unsubstituted bipyrrole. All of these new compounds display a moderate fluorescence. In contrast with unsubstituted bipyrroles, these bipyrroles are endowed with a high chemical and thermal stability and solubility in organic solvents

Quaterpyrroles as Building Blocks for the Synthesis of Expanded Porphyrins

A new family of quaterpyrroles and their application as building blocks for the synthesis of macrocycles is reported. The preparation of these quaterpyrroles consisted of two synthetic steps: bromination of 2,2′-bipyrroles bearing two electron-withdrawing groups followed by Suzuki coupling with 1-(<i>tert</i>-butoxy­carbonyl)­pyrrole-2-boronic acid. The resulting quaterpyrroles have been used to prepare an octaphyrin and a substituted cyclo[8]­pyrrole. Additionally, the synthesis of a new macrocycle containing the quaterpyrrole and 2,5-di­(1<i>H</i>-pyrrol-2-yl)­thio­phene moieties is presented

Quaterpyrroles as Building Blocks for the Synthesis of Expanded Porphyrins

A new family of quaterpyrroles and their application as building blocks for the synthesis of macrocycles is reported. The preparation of these quaterpyrroles consisted of two synthetic steps: bromination of 2,2′-bipyrroles bearing two electron-withdrawing groups followed by Suzuki coupling with 1-(<i>tert</i>-butoxy­carbonyl)­pyrrole-2-boronic acid. The resulting quaterpyrroles have been used to prepare an octaphyrin and a substituted cyclo[8]­pyrrole. Additionally, the synthesis of a new macrocycle containing the quaterpyrrole and 2,5-di­(1<i>H</i>-pyrrol-2-yl)­thio­phene moieties is presented

Design of a Nanostructured Active Surface against Gram-Positive and Gram-Negative Bacteria through Plasma Activation and in Situ Silver Reduction

Nowadays there is an increasing focus for avoiding bacterial colonization in a medical device after implantation. Bacterial infection associated with prosthesis implantation, or even along the lifetime of the implanted prosthesis, entails a serious problem, emphasized with immunocompromised patients. This work shows a new methodology to create highly hydrophobic micro-/nanostructured silver antibacterial surfaces against Gram-positive and Gram-negative bacteria, using low-pressure plasma. PDMS (polydimethylsiloxane) samples, typically used in tracheal prosthesis, are coated with PFM (pentafluorophenyl methacrylate) through PECVD (plasma enhance chemical vapor deposition) technique. PFM thin films offer highly reactive ester groups that allow them to react preferably with amine bearing molecules, such as amine sugar, to create controlled reductive surfaces capable of reducing silver salts to a nanostructured metallic silver. This micro-/nanostructured silver coating shows interesting antibacterial properties combined with an antifouling behavior causing a reduction of Gram-positive and Gram-negative bacteria viability. In addition, these types of silver-coated samples show no apparent cytotoxicity against COS-7 cells

Novel ¹⁸F Labeling Strategy for Polyester-Based NPs for in Vivo PET-CT Imaging

Drug-loaded nanocarriers and nanoparticulate systems used for drug release require a careful in vivo evaluation in terms of physicochemical and pharmacokinetic properties. Nuclear imaging techniques such as positron emission tomography (PET) are ideal and noninvasive tools to investigate the biodistribution and biological fate of the nanostructures, but the incorporation of a positron emitter is required. Here we describe a novel approach for the ¹⁸F-radiolabeling of polyester-based nanoparticles. Our approach relies on the preparation of the radiolabeled active agent 4-[¹⁸F]­fluorobenzyl-2-bromoacetamide ([¹⁸F]­FBBA), which is subsequently coupled to block copolymers under mild conditions. The labeled block copolymers are ultimately incorporated as constituent elements of the NPs by using a modified nano coprecipitation method. This strategy has been applied in the current work to the preparation of peptide-functionalized NPs with potential applications in drug delivery. According to the measurements of particle size and zeta potential, the radiolabeling process did not result in a statistically significant alteration of the physicochemical properties of the NPs. Moreover, radiochemical stability studies showed no detachment of the radioactivity from NPs even at 12 h after preparation. The radiolabeled NPs enabled the in vivo quantification of the biodistribution data in rats using a combination of imaging techniques, namely, PET and computerized tomography (CT). Low accumulation of the nanoparticles in the liver and their elimination mainly via urine was found. The different biodistribution pattern obtained for the “free” radiolabeled polymer suggests chemical and radiochemical integrity of the NPs under investigation. The strategy reported here may be applied to any polymeric NPs containing polymers bearing a nucleophile, and hence our novel strategy may find application for the in vivo and noninvasive investigation of a wide range of NPs