ABSTRACT
A simple electrochemical fabrication of graphene nanomesh (GNM) via colloidal templating is reported for the first time. The process involves the arraying of polystyrene (PS) spheres onto a CVD-deposited graphene, electro-deposition of carbazole units, removal of the PS template and electrochemical oxidative etching. The GNM was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Raman spectroscopy.
Subject(s)
Electrochemical Techniques , Graphite/chemistry , Nanostructures/chemistry , Carbazoles/chemistry , Colloids/chemistry , Molecular Structure , Particle Size , Polystyrenes/chemistry , Surface PropertiesABSTRACT
The Langmuir-Blodgett (LB) technique was used to immobilize flat graphene oxide (GO) sheets on a PET substrate to ascertain as to whether the edges of GO play an integral part in its antimicrobial mechanism. The observed antibacterial activity suggests that contact with the edges is not a fundamental part of the mechanism.
ABSTRACT
The synthesis of homopolymer and diblock copolymers on surfaces was demonstrated using electrodeposition of a methacrylate-functionalized carbazole dendron and subsequent reversible addition-fragmentation chain transfer (RAFT) "grafting-through" polymerization. First, the anodically electroactive carbazole dendron with methacrylate moiety (G1CzMA) was electrodeposited over a conducting surface (i.e. gold or indium tin oxide (ITO)) using cyclic voltammetry (CV). The electrodeposition process formed a crosslinked layer of carbazole units bearing exposed methacrylate moieties. This film was then used as the surface for RAFT polymerization process of methyl methacrylate (MMA), styrene (S), and tert-butyl acrylate (TBA) in the presence of a free RAFT agent and a free radical initiator, resulting in grafted polymer chains. The molecular weights and the polydispersity indices (PDI) of the sacrificial polymers were determined by gel permeation chromatography (GPC). The stages of surface modification were investigated using X-ray photoelectron spectroscopy (XPS), ellipsometry, and atomic force microscopy (AFM) to confirm the surface composition, thickness, and film morphology, respectively. UV-Vis spectroscopy also confirmed the formation of an electro-optically active crosslinked carbazole film with a [Formula: see text] - [Formula: see text] absorption band from 450-650nm. Static water contact angle measurements confirmed the changes in surface energy of the ultrathin films with each modification step. The controlled polymer growth from the conducting polymer-modified surface suggests the viability of combining electrodeposition and grafting-through approach to form functional polymer ultrathin films.
Subject(s)
Electroplating/methods , Methacrylates/chemistry , Polymerization , Polymers/chemistry , Acrylates/chemistry , Anthracenes/chemistry , Carbazoles/chemistry , Electric Conductivity , Electrochemistry , Electrodes , Optical Phenomena , Styrene/chemistry , Surface PropertiesABSTRACT
Hepatitis C is transmitted primarily parenterally by contaminated blood and is often associated with: intravenous drug abuse, invasive procedures, blood transfusions, acupuncture, tattooing, and alcohol and tobacco use. This study aimed to quantify and evaluate the risk factors among blood donors, volunteer blood donors and replacement individuals, infected or not by the C virus. The main transmission routes of C virus were identified in 55 men and 25 women (GI) monitored by the Ambulatory Unit of the Department of Tropical Diseases, Botucatu Medical School, and 24 men and 26 women (GII), all active blood donors at the Bauru State Hospital Transfusional Agency. Both groups were similar in: tobacco and alcohol consumption, sexual behavior, tattooing and illicit drug use. The duration of alcohol and tobacco consumption and blood transfusions in GI were longer, whereas the option for steady partners, condom use, disposable materials and piercings were predominant in GII. In conclusion, the risk factors for hepatitis C demonstrate the necessity of health policies that act on the primary and secondary prevention levels (respectively, reduction of infection incidence and hepatopathy risk)
