In this work, "neg." fingermarks have been developed on paper, even after soaking in water, by the application of a new bifunctional reagent attached to gold nanoparticles, and then a silver phys. developer. The bifunctional reagent is composed of an active head, i.e., a polar group with high affinity to cellulose, attached by a long chain to an active tail contg. a sulfur group, which can stabilize gold nanoparticles. Through the active head, the gold nanoparticles, which are stabilized by the active tail, adhere preferentially to the paper cellulose rather than to the fingerprint material, to which they conventionally bind. Consequently, silver developer, which normally develops sebaceous fingermarks by pptg. dark silver on the sebaceous material, ppt. preferentially on the gold-coated areas giving rise to the appearance of uncolored ridge detail on a dark background. In this competing process, the paper itself serves as the substrate, whereas the fingermarks serve as a mask. This process may increase the overall yield of developed fingermarks as it bypasses the issue of the remarkable differences in sweat compn. between individual persons. [on SciFinder(R)]

The deposition of Au and Ag, locally and from bulk solution, on poly(3,4-ethylenedioxythiophene) (PEDOT) was studied. Specifically, PEDOT was electrochemically polymerized onto a glassy carbon (GC) electrode and used for bulk deposition of Au and Ag from their respective ions dissolved in the solution as well as for the local deposition of these metals using scanning electrochemical microscopy (SECM). These two sets of experiments were utilized to investigate the difference between Au and Ag electrochemical deposition on PEDOT. In particular, SECM experiments, which were conducted by the controlled anodic dissolution of Au and Ag microelectrodes close to GC/PEDOT, probed the effect of different PEDOT oxidation states on local deposition. The current-time transients recorded during the deposition, combined with scanning electron microscopy and EDX analysis provided insight into the reduction processes. AuCl(4)(-) and Ag(+) ions were electrochemically reduced at a potential equal to and more negative than the ions redox potentials (0.4 and 0.2 V, respectively) and more positive than -0.7 V, where the PEDOT starts transforming into the reduced, i.e. insulating, state. We found that the electroreduction of Ag(+) ions was diffusion-controlled and the PEDOT film served as a simple conductor. On the other hand, the reduction of AuCl(4)(-) ions was enhanced on GC/PEDOT as compared with bare GC, indicating that PEDOT catalyzes the reduction of AuCl(4)(-) to Au.[on SciFinder (R)]

The deposition of Au and Ag, locally and from bulk soln., on poly(3,4-ethylenedioxythiophene) (PEDOT) was studied. Specifically, PEDOT was electrochem. polymd. onto a glassy carbon (GC) electrode and used for bulk deposition of Au and Ag from their resp. ions dissolved in the soln. as well as for the local deposition of these metals using scanning electrochem. microscopy (SECM). These two sets of expts. were utilized to investigate the difference between Au and Ag electrochem. deposition on PEDOT. In particular, SECM expts., which were conducted by the controlled anodic dissoln. of Au and Ag microelectrodes close to GC/PEDOT, probed the effect of different PEDOT oxidn. states on local deposition. The current-time transients recorded during the deposition, combined with SEM and energy-dispersive x-ray anal. provided insight into the redn. processes. AuCl4- and Ag+ ions were electrochem. reduced at a potential equal to and more neg. than the ions redox potentials (0.4 and 0.2 V, resp.) and more pos. than -0.7 V, where the PEDOT starts transforming into the reduced, i.e. insulating, state. We found that the electroredn. of Ag+ ions was diffusion-controlled and the PEDOT film served as a simple conductor. The redn. of AuCl4- ions was enhanced on GC/PEDOT as compared with bare GC, indicating that PEDOT catalyzes the redn. of AuCl4- to Au. [on SciFinder(R)]

The electrochemical determination of low levels of Cd using a self-assembled monolayer (SAM) modified Au electrode is reported. Determination was based on the stripping of Cd, which was deposited by under potential deposition (UPD). A series of short alkanethiol SAMs bearing different end groups, i.e., sulfonate, carboxylate and ammonium, were examined. Lowest level of detection (ca. 50 ngL(-1)) was achieved with a 3-mercaptopropionic acid (MPA) monolayer using subtractive anodic square wave voltammetry (SASV). Additional surface methods, namely, reductive desorption and X-ray photoelectron spectroscopy, were applied to determine the interfacial structure of the electrodeposited Cd on the modified electrodes. We conclude that the deposited Cd forms a monoatomic layer, which bridges between the gold surface and the alkanethiol monolayer associating with both the gold and the sulfur atoms.[on SciFinder (R)]

The electrochem. detn. of low levels of Cd using a self-assembled monolayer (SAM) modified Au electrode is reported. Detn. was based on the stripping of Cd, which was deposited by under potential deposition (UPD). Short alkanethiol SAMs bearing different end groups, i.e., sulfonate, carboxylate and ammonium, were examd. Lowest level of detection (\~50 ng/L-1) was achieved with a 3-mercaptopropionic acid (MPA) monolayer using subtractive anodic square wave voltammetry (SASV). Addnl. surface methods, namely, reductive desorption and XPS, were applied to det. the interfacial structure of the electrodeposited Cd on the modified electrodes. The deposited Cd forms a monoat. layer, which bridges between the gold surface and the alkanethiol monolayer assocg. with both the gold and the sulfur atoms. [on SciFinder(R)]

A review on the various studies of electroplating of medical devices, such as implants, including the different methods of electrochem. deposition and the various substrates electrochem. coated. [on SciFinder(R)]

Biodegradable nanoparticles represent a promising platform for controlled release and other applications in medicine. To alter the interface of the medical device with the living tissue successfully, a thin coating needs to be applied onto the surface. The traits and functionality of the coating depends on its components, which in the presented work are sol-gel and biodegradable nanoparticles (NPs) deposited onto the substrate using the electrochem. sol-gel method. Aspects affecting the deposition process were investigated such as the applied potential and its duration. The properties of the deposits with emphasis on the biodegradable NPs within the deposited films were characterized and studied. Another element examd. was the loading ability of the NPs. A fluorescent org. mol. was incorporated in the biodegradable NPs as a drug model, to demonstrate loading capability. [on SciFinder(R)]

A new approach for the local deposition of sol-gel films on conducting and insulating surfaces using scanning electrochem. microscopy (SECM) via the feedback and direct modes is presented. Patterning is based on enhancing sol-gel condensation by altering the local pH due to H2O electrolysis as a result of applying neg. potentials. [on SciFinder(R)]

A new approach for the local deposition of sol-gel films on conducting and insulating surfaces using scanning electrochemical microscopy (SECM) via the feedback and direct modes is presented. Patterning is based on enhancing sol-gel condensation by altering the local pH due to water electrolysis as a result of applying negative potentials.[on SciFinder (R)]

Indium tin oxide (ITO) is the most commonly used transparent conducting substance. It has been used in numerous applications such as light-emitting diodes. In most applications and studies, the ITO surface is further coated with addnl. layers. The interface between the ITO and the coating is of utmost importance since it affects the phys. and chem. properties of the final device. Improving the adhesion between ITO and a coating layer can be achieved by applying a "mol. adhesive" as an inter-phasing mol. layer. In this study, we used 3-(trimethoxysilyl)propyl methacrylate as a "mol. adhesive" for better connection between ITO and a polymethacrylate layer. The samples were studied by electrochem., contact angle goniometry, at. force microscopy, and nano scratch microscopy. These studies clearly show that a simple silanization process formed a thin mol. adhesive layer, which did not influence the phys. and chem. properties of the final coated electrode and at the same time increased significantly the adhesion between the ITO and the polymethacrylate coating. [on SciFinder(R)]

The essence of this study is to apply the Langmuir-Blodgett (LB) technique for assembling asym. membranes. Accordingly, Langmuir films of a (further) polymerizable polymer, 1,2-polybutadiene (1,2-pbd), were studied and transferred onto different solid supports, such as Au, In Sn oxide (ITO), and Si. The layers were characterized both at the air/H2O interface as well as on different substrates using numerous methods including cyclic voltammetry, impedance spectroscopy, spectroscopic ellipsometry, at. force microscopy, XPS, and reflection-absorption FTIR spectroscopy. The Langmuir films were stable at the air-H2O interface as long as they were not exposed to UV irradn. The LB films formed disorganized layers, which gradually blocked the permeation of different species with increasing the no. of deposited layers. The thickness was \~4-7 Å per layer. Irradiating the Langmuir films caused their crosslinking at the air-H2O interface. Also, the authors took advantage of the reactivity of the double bond of the LB films on the solid supports and graft polymd. acrylic acid on top of the 1,2-pbd layers. This approach is the basis of the formation of an asym. membrane that requires different porosity on both of its sides. [on SciFinder(R)]