Publications by Year: 2011

2011
Noyhouzer T, Mandler D. Determination of low levels of cadmium ions by the under potential deposition on a self-assembled monolayer on gold electrode. Anal Chim ActaAnalytica chimica acta. 2011;684 (1-2) :1 - 7.Abstract
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)]
Liu L, Toledano R, Danieli T, Zhang J-Q, Hu J-M, Mandler D. Electrochemically patterning sol-gel structures on conducting and insulating surfaces. Chem Commun (Camb)Chemical communications (Cambridge, England). 2011;47 (24) :6909 - 11.Abstract
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)]
Danieli T, Colleran J, Mandler D. Deposition of Au and Ag nanoparticles on PEDOT. Phys Chem Chem PhysPhysical chemistry chemical physics : PCCP. 2011;13 (45) :20345 - 53.Abstract
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)]
Hitrik M, Gutkin V, Lev O, Mandler D. Preparation and characterization of mono- and multilayer films of polymerizable 1,2-polybutadiene using the Langmuir-Blodgett technique. LangmuirLangmuir : the ACS journal of surfaces and colloids. 2011;27 (19) :11889 - 98.Abstract
The essence of this study is to apply the Langmuir-Blodgett (LB) technique for assembling asymmetric 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 gold, indium tin oxide (ITO), and silicon. The layers were characterized both at the air/water interface as well as on different substrates using numerous methods including cyclic voltammetry, impedance spectroscopy, spectroscopic ellipsometry, atomic force microscopy, X-ray photoelectron spectroscopy, and reflection-absorption Fourier transform infrared spectroscopy. The Langmuir films were stable at the air-water interface as long as they were not exposed to UV irradiation. The LB films formed disorganized layers, which gradually blocked the permeation of different species with increasing the number of deposited layers. The thickness was ca. 4-7 Å per layer. Irradiating the Langmuir films caused their cross-linking at the air-water interface. Furthermore, we took advantage of the reactivity of the double bond of the LB films on the solid supports and graft polymerized acrylic acid on top of the 1,2-pbd layers. This approach is the basis of the formation of an asymmetric membrane that requires different porosity on both of its sides.[on SciFinder (R)]
Noyhouzer T, Mandler D. Determination of low levels of cadmium ions by the under potential deposition on a self-assembled monolayer on gold electrode. Anal. Chim. ActaAnalytica Chimica Acta. 2011;684 (1-2) :1 - 7.Abstract
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)]
Gdor E, Mandler D. Electrochemically assisted deposition of biodegradable polymer nanoparticles/sol-gel thin films. J. Mater. Chem.Journal of Materials Chemistry. 2011;21 (32) :12145 - 12150.Abstract
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)]
Liu L, Toledano R, Danieli T, Zhang J-Q, Hu J-M, Mandler D. Electrochemically patterning sol-gel structures on conducting and insulating surfaces. Chem. Commun. (Cambridge, U. K.)Chemical Communications (Cambridge, United Kingdom). 2011;47 (24) :6909 - 6911.Abstract
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)]
Mandler D, Kraus-Ophir S. Self-assembled monolayers (SAMs) for electrochemical sensing. J. Solid State Electrochem.Journal of Solid State Electrochemistry. 2011;15 (7-8) :1535 - 1558.Abstract
A review. The past, present, and future of the application of self-assembled monolayers (SAMs) in electroanal. chem. is reviewed. SAMs for electroanal. applications were introduced in the early 1990s and since then were exploited for the detection of different species ranging from metal ions to biomols. and microorganisms. This review describes the different types of monolayers, surfaces on which they were assembled, the various analytes, which were detd., and the various electrochem. techniques employed. The prospective and perspectives of this topic are discussed. [on SciFinder(R)]
Malel E, Colleran J, Mandler D. Studying the localized deposition of Ag nanoparticles on self-assembled monolayers by scanning electrochemical microscopy (SECM). Electrochim. ActaElectrochimica Acta. 2011;56 (20) :6954 - 6961.Abstract
The local deposition of Ag nanoparticles (NPs) on ω-mercaptoalkanoic acid, HS(CH2)nCO2H, (n = 2, 10) self-assembled monolayers (SAMs) by scanning electrochem. microscopy (SECM) is reported. We found that the presence of a SAM had a pronounced effect on Ag deposition. Expts. were conducted by applying different potentials to an Au(1 1 1) substrate either in the presence of a const. concn. of Ag+ ions in soln. (bulk deposition) or by generating a flux of Ag+ from an Ag microelectrode that was positioned close to the Au(1 1 1) substrate (SECM deposition). SECM was used for generating a controlled flux of silver ions by anodic dissoln. of an Ag microelectrode close to the SAMs modified Au(1 1 1). We found that the shape of the NPs was affected by the length of the carbon-chain of the SAM. Tetrahedral NPs were obtained on bare Au(1 1 1) surfaces while rod like and cubic Ag NPs were deposited onto 3-mercaptopropanoic acid (MPA) and 11-mercaptoundecanoic acid (MUA) SAMs, resp. The size and shape of the deposited NPs were influenced by the deposition potential. We conclude that the shape and distribution of locally deposited Ag NPs on Au(1 1 1) can be controlled by modification of the substrate with a SAM and through controlling the Ag+ flux generated by SECM. [on SciFinder(R)]
Danieli T, Colleran J, Mandler D. Deposition of Au and Ag nanoparticles on PEDOT. Phys. Chem. Chem. Phys.Physical Chemistry Chemical Physics. 2011;13 (45) :20345 - 20353.Abstract
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)]
Guslitzer-Okner R, Mandler D. Electrochemical coating of medical implants. Mod. Aspects Electrochem.Modern Aspects of Electrochemistry. 2011;52 (Applications of Electrochemistry and Nanotechnology in Biology and Medicine I) :291 - 342.Abstract
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)]
Ginzburg-Turgeman R, Guion J-B, Mandler D. Improving the adhesion of polymethacrylate thin films onto indium tin oxide electrodes using a silane-based "Molecular Adhesive". J. Solid State Electrochem.Journal of Solid State Electrochemistry. 2011;15 (11-12) :2401 - 2407.Abstract
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)]
Hitrik M, Gutkin V, Lev O, Mandler D. Preparation and Characterization of Mono- and Multilayer Films of Polymerizable 1,2-Polybutadiene Using the Langmuir-Blodgett Technique. LangmuirLangmuir. 2011;27 (19) :11889 - 11898.Abstract
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)]
Kraus-Ophir S, Jerman I, Orel B, Mandler D. Symmetrical thiol functionalized polyhedral oligomeric silsesquioxanes as building blocks for LB films. Soft MatterSoft Matter. 2011;7 (19) :8862 - 8869.Abstract
The Langmuir-Blodgett (LB) method was used for depositing cubic polyhedral oligomeric silsesquioxanes (T8POSS) onto Au, indium tin oxide (ITO) and mica supports. Three different T8POSS were examd.; two were amphiphilic and aggregated upon transfer to a solid support, while the highly sym. POSS (termed MP8) gave stable and reproducible Langmuir films as studied by surface pressure and transfer ratio measurements. This was attributed to the eight identical alkanethiol groups located on each of the eight corners of the cubic like skeleton. The LB films were studied by RA-FTIR, XPS, contact angle and cyclic voltammetry. These techniques revealed the formation of a permeable, yet, stable layer. The sym. MP8 was utilized as a bridging building block between the support and Au nanoparticles (Au-NPs). This assembly was examd. by means of AFM, SEM and anodic oxidn. of the nanoparticles. An av. d. of 1.45 × 109 nanoparticles cm-2 was obtained for the deposited Au-NPs on the MP8 layer. Furthermore, anodic stripping voltammetry was used for studying the extn. of Hg2+ by the MP8 LB film. [on SciFinder(R)]