Publications by Year: 2014

2014
Wang Z, Zhang J, Zhu C, Wu S, Mandler D, Marks RS, Zhang H. Amplified detection of femtomolar DNA based on a one-to-few recognition reaction between DNA-Au conjugate and target DNA. NanoscaleNanoscale. 2014;6 (6) :3110 - 5.Abstract
A sensitive electrochemical DNA biosensor based on the amplification of Au nanoparticles (AuNPs) has been developed. The AuNPs were modified with two types of signaling reporter DNAs, i.e. a methylene blue probe (MB-probe 2-SH) and T10 with a methylene blue signaling molecule (MB-T10-SH), forming DNA-AuNP conjugates. The MB-probe 2-SH is complementary to the target DNA, while MB-T10-SH is not. The presence of MB-T10-SH reduces the cross-reaction between target DNA and MB-probe 2-SH on the AuNPs, resulting in increased sensitivity of the biosensor. In our assay, the DNA sensor is fabricated by immobilizing a capture probe on the surface of the Au electrode, which then hybridizes with the corresponding target DNA, and further hybridizes with a DNA-Au conjugate. The signal of MB is measured by differential pulse voltammetry, while the DNA-Au conjugate enables the detection of target DNA in the linear range of 10(-13) to 10(-8) M with the detection limit as low as 50 fM.[on SciFinder (R)]
Liu L, Tan C, Chai J, Wu S, Radko A, Zhang H, Mandler D. Electrochemically "writing" graphene from graphene oxide. SmallSmall (Weinheim an der Bergstrasse, Germany). 2014;10 (17) :3555 - 9.Abstract
A novel approach of patterning graphene on conductive surfaces based on local electrochemical reduction of graphene oxide is reported. Graphene is "written" from typical graphene oxide dispersion by applying negative potential on conductive surfaces vs. a micrometer-sized counter electrode "pen" with scanning electrochemical microscopy (SECM). Micrometer scaled patterns are successfully generated on gold and stainless steel surfaces.[on SciFinder (R)]
Hitrik M, Lev O, Mandler D. In situ electrodeposition of an asymmetric sol-gel membrane based on an octadecyltrimethoxysilane Langmuir film. ChemistryChemistry (Weinheim an der Bergstrasse, Germany). 2014;20 (38) :12104 - 13.Abstract
The unique properties of Langmuir film formation were utilized in assembling a thin skin of an asymmetric membrane. An octadecyltrimethoxysilane (ODTMS) Langmuir monolayer was formed at the air-water interface and served as the substrate for growing a bulky sol-gel polymer in situ. The latter was based on the electrochemical deposition of tetramethoxysilane dissolved in the water subphase by means of horizontal touch electrochemistry. The resultant asymmetric layer that consisted of a thin hydrophobic ODTMS Langmuir film connected to a bulk hydrophilic sol-gel network was studied in situ and ex situ by using various techniques, such as cyclic voltammetry, electrochemical impedance spectroscopy (EIS), scanning electron microscopy, transmission electron microscopy (TEM), and goniometry. We found that a porous hydrophilic film grew on top of a hydrophobic layer as was evident from TEM, contact angle, and EIS analyses. The film thickness and film permeability could be controlled by changing the deposition conditions such as the potential window applied and its duration. Hence, this method offers an alternative approach for assembling asymmetric films for various applications.[on SciFinder (R)]
Kraus-Ophir S, Witt J, Wittstock G, Mandler D. Nanoparticle-imprinted polymers for size-selective recognition of nanoparticles. Angew Chem Int Ed EnglAngewandte Chemie (International ed. in English). 2014;53 (1) :294 - 8.Abstract
Citrate-stabilized gold nanoparticles 15 nm and 33 nm in diameter were transferred concomitantly with a monolayer of positively charged polyaniline by Langmuir-Blodgett transfer at pH 5 onto a conducting indium-doped tin oxide (ITO) support. Films consisting of one to three layers of polyaniline with thicknesses of 1-3 nm were prepared and characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy. After electro-oxidation of the Au nanoparticles in 0.1 M KCl, cavities were left behind in the film that could be analyzed by SEM. These cavities were able to recapture analyte nanoparticles from a solution of pH 10 and showed size-exclusion properties. The amount of nanoparticles taken up by the cavities was conveniently analyzed by measuring the charge associated with the electro-oxidation of these particles in 0.1 M KCl after the film had been rinsed with water. The size-exclusion properties improved with the number of Langmuir-Blodgett layers transferred.[on SciFinder (R)]
Layani M, Darmawan P, Foo WL, Liu L, Kamyshny A, Mandler D, Magdassi S, Lee PS. Nanostructured electrochromic films by inkjet printing on large area and flexible transparent silver electrodes. NanoscaleNanoscale. 2014;6 (9) :4572 - 6.Abstract
Printed electrochromic flexible films were obtained by combining transparent silver grid electrodes formed by self-assembly and inkjet printed WO3 nanoparticles. Concentrated dispersions of WO3 nanoparticles were inkjet printed on transparent plastic silver grid electrodes with a high transparency of 83% in the spectral range of 400-800 nm, and a low sheet resistance in the range of 1-5 Ω sq(-1). These electrodes were used for electrochromic applications for the first time. The resultant patterned nanostructured electrochromic films maintained their coloring and bleaching performance after bending of the flexible films.[on SciFinder (R)]
Metoki N, Liu L, Beilis E, Eliaz N, Mandler D. Preparation and characterization of alkylphosphonic acid self-assembled monolayers on titanium alloy by chemisorption and electrochemical deposition. LangmuirLangmuir : the ACS journal of surfaces and colloids. 2014;30 (23) :6791 - 9.Abstract
Ti-6Al-4V alloy is the most commonly used alloy for dental and orthopedic implants. In order to improve osseointegration, different surface modification methods are usually employed, including self-assembled monolayers (SAMs). This study presents an investigation of both active (electroassisted) and passive (adsorption) approaches for the modification of Ti-6Al-4V using alkylphosphonic acid. The monolayers were characterized by cyclic voltammetry, double-layer capacitance, contact angle measurements, X-ray photoelectron spectroscopy, polarization modulation infrared reflection adsorption spectroscopy, electrochemical impedance spectroscopy, and corrosion potentiodynamic polarization measurements. It is shown that the electrochemically assisted monolayers, which are assembled faster, exhibit better control over surface properties, a superior degree of order, and a somewhat higher packing density. The electrosorbed SAMs also exhibit better blockage of electron transfer across the interface and thus have better corrosion resistance.[on SciFinder (R)]
Wang Z, Zhang J, Zhu C, Wu S, Mandler D, Marks RS, Zhang H. Amplified detection of femtomolar DNA based on a one-to-few recognition reaction between DNA-Au conjugate and target DNA. NanoscaleNanoscale. 2014;6 (6) :3110 - 3115.Abstract
A sensitive electrochem. DNA biosensor based on the amplification of Au nanoparticles (AuNPs) has been developed. The AuNPs were modified with two types of signaling reporter DNAs, i.e. a methylene blue probe (MB-probe 2-SH) and T10 with a methylene blue signaling mol. (MB-T10-SH), forming DNA-AuNP conjugates. The MB-probe 2-SH is complementary to the target DNA, while MB-T10-SH is not. The presence of MB-T10-SH reduces the cross-reaction between target DNA and MB-probe 2-SH on the AuNPs, resulting in increased sensitivity of the biosensor. In our assay, the DNA sensor is fabricated by immobilizing a capture probe on the surface of the Au electrode, which then hybridizes with the corresponding target DNA, and further hybridizes with a DNA-Au conjugate. The signal of MB is measured by differential pulse voltammetry, while the DNA-Au conjugate enables the detection of target DNA in the linear range of 10-13 to 10-8 M with the detection limit as low as 50 fM. [on SciFinder(R)]
Liu L, Tan C, Chai J, Wu S, Radko A, Zhang H, Mandler D. Electrochemically "writing" graphene from graphene oxide. SmallSmall. 2014;10 (17) :3555 - 3559.Abstract
Graphene has been successfully patterned on stainless steel and gold at micrometer-scale resoln. The concept is based on the electrochem. redn. of graphene oxide on conductive surfaces localized by a microelectrode that is positioned close to the surface. [on SciFinder(R)]
Kraus-Ophir S, Witt J, Wittstock G, Mandler D. Nanoparticle-Imprinted Polymers for Size-Selective Recognition of Nanoparticles. Angew. Chem., Int. Ed.Angewandte Chemie, International Edition. 2014;53 (1) :294 - 298.Abstract
Citrate-stabilized gold nanoparticles 15 nm and 33 nm in diam. were transferred concomitantly with a monolayer of pos. charged polyaniline by Langmuir-Blodgett transfer at pH 5 onto a conducting indium-doped tin oxide (ITO) support. Films consisting of one to three layers of polyaniline with thicknesses of 1-3 nm were prepd. and characterized by SEM, at. force microscopy (AFM), and XPS. After electrooxidn. of the Au nanoparticles in 0.1 M KCl, cavities were left behind in the film that could be analyzed by SEM. These cavities were able to recapture analyte nanoparticles from a soln. of pH 10 and showed size-exclusion properties. The amt. of nanoparticles taken up by the cavities was conveniently analyzed by measuring the charge assocd. with the electrooxidn. of these particles in 0.1 M KCl after the film had been rinsed with water. The size-exclusion properties improved with the no. of Langmuir-Blodgett layers transferred. [on SciFinder(R)]
Tulchinsky D, Uvarov V, Popov I, Mandler D, Magdassi S. A novel non-selective coating material for solar thermal potential application formed by reaction between sol-gel titania and copper manganese spinel. Sol. Energy Mater. Sol. CellsSolar Energy Materials & Solar Cells. 2014;120 (PA) :23 - 29.Abstract
A method for prepg. a novel bixbyite non-selective coating for solar thermal conversion is described. The coating is formed by a thermal reaction between a titania sol-gel precursor with a copper manganese spinel to form a new material, Cu0.44Ti0.44Mn0.84Fe0.28O3, with a bixbyite structure. The effect of temp. and ratio between the two components on the formation of the bixbyite layer (deposited on Inconel by spray-coating) was studied. The absorptance of the films (AM 1.5; 335-2500 nm) with a thickness of 10±2 μm after annealing at 2 h at 650 °C and 750 °C was 97.4% and 94.7%, resp. This synthesis represents a novel approach in which the final solar thermal coating is formed as a continuous and uniform layer which combines both the absorber and the ceramic binder. The developed material shows promising results for future applications as absorber in solar thermal energy conversion. [on SciFinder(R)]
Ling H, Lu J, Phua S, Liu H, Liu L, Huang Y, Mandler D, Lee PS, Lu X. One-pot sequential electrochemical deposition of multilayer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonic acid)/tungsten trioxide hybrid films and their enhanced electrochromic properties. J. Mater. Chem. AJournal of Materials Chemistry A: Materials for Energy and Sustainability. 2014;2 (8) :2708 - 2717.Abstract
Hybrid thin films composed of multilayer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonic acid) (PEDOT:PSS) and W trioxide (WO3) were electrochem. deposited on In Sn oxide (ITO) from a 1-pot soln. using a square-wave galvanostatic method. The morphol. of the hybrid thin films could be easily manipulated to optimize their electrochromic properties by adjusting deposition conditions. In the hybrids, both components can be simultaneously switched to colored or bleached states. The hybrid film obtained with very short deposition times of PEDOT:PSS and WO3 in each cycle exhibits significantly enhanced electrochromic properties. The optical contrast of the hybrid film is higher than that of PEDOT:PSS or WO3 films of the same thickness. Also, the stability of the hybrid film is also drastically enhanced. The enhancement may be attributed to the favorable interactions between the two components, i.e., PEDOT:PSS may enter the defect sites in electrodeposited WO3, preventing surface-defect-induced anodic dissoln. during cycling, while the surface functional groups of WO3 may act as dopants to inhibit over-oxidn. of PEDOT, as well as the large interfacial area created using this unique 1-pot multilayer deposition method. [on SciFinder(R)]
Cao X, Wang N, Magdassi S, Mandler D, Long Y. Europium doped vanadium dioxide material: reduced phase transition temperature, enhanced luminous transmittance and solar modulation. Sci. Adv. Mater.Science of Advanced Materials. 2014;6 (3) :558 - 561.Abstract
Vanadium dioxide is a well-known near room temp. phase transition material with a transition temp. (τC) at 68 °C. In this paper, Eu3+ dopant with different doping levels was introduced into the crystal lattice of VO2. The thermochromic properties, including the integrated visible transmittance (Tlum) and the solar modulating ability (ΔTsol) were favorably affected by the Eu-doping. It is of great interest that the substitution of V4+ by Eu3+ in the VO2 crystal structure reduced the τC from 68 °C to 47.5 °C with an approx. decreasing rate of 6.5 °C/at% up to 4 at%. More importantly, the Eu dopant helped in improving the properties of luminous transmittance and solar modulating ability, which were difficult to be achieved by other dopants. [on SciFinder(R)]
Magdassi S, Mandler D, Baidossi M, Larush L, Zwicker C, Nirenberg A, Binyamin Y.; 2014. High absorptivity, heat resistant coatings and related apparatus and methods.Abstract
A paint formulation can include an inorg. oxide-based pigment and an org. binder. The org. binder can be irreversibly converted to an inorg. binder upon curing of the paint formulation at a temp. greater than 200° C. The oxide-based pigment and/or the paint formulation itself can have an absorptivity of at least 80% with respect to the AM 1.5 spectrum. The paint formulation can also include at least one org. solvent, an inorg. filler, and/or at least one additive. Such paint formulations may be stable at high temps. (e.g., 750° C.) and can be used as solar-radiation-absorbing heat-resistant coatings for components of a solar tower system. [on SciFinder(R)]
Hitrik M, Lev O, Mandler D. In situ electrodeposition of an asymmetric sol-gel membrane based on an octadecyltrimethoxysilane langmuir film. Chem. - Eur. J.Chemistry - A European Journal. 2014;20 (38) :12104 - 12113.Abstract
The unique properties of Langmuir film formation were utilized in assembling a thin skin of an asym. membrane. An octadecyltrimethoxysilane (ODTMS) Langmuir monolayer was formed at the air-water interface and served as the substrate for growing a bulky sol-gel polymer in situ. The latter was based on the electrochem. deposition of tetramethoxysilane dissolved in the water subphase by means of horizontal touch electrochem. The resultant asym. layer that consisted of a thin hydrophobic ODTMS Langmuir film connected to a bulk hydrophilic sol-gel network was studied in situ and ex situ by using various techniques, such as cyclic voltammetry, electrochem. impedance spectroscopy (EIS), SEM, transmission electron microscopy (TEM), and goniometry. We found that a porous hydrophilic film grew on top of a hydrophobic layer as was evident from TEM, contact angle, and EIS analyses. The film thickness and film permeability could be controlled by changing the deposition conditions such as the potential window applied and its duration. Hence, this method offers an alternative approach for assembling asym. films for various applications. [on SciFinder(R)]
Liu L, Layani M, Yellinek S, Kamyshny A, Ling H, Lee PS, Magdassi S, Mandler D. "Nano to nano" electrodeposition of WO3 crystalline nanoparticles for electrochromic coatings. J. Mater. Chem. AJournal of Materials Chemistry A: Materials for Energy and Sustainability. 2014;2 (38) :16224 - 16229.Abstract
A nano to nano electrodeposition approach for prepg. nano-structured thin films from the dispersion of nano-objects is reported. A typical WO3 system is demonstrated, where nanocryst. films are electrodeposited onto transparent conductive electrodes such as ITO and Ag grid printed PET (Ag grid/PET) from the H2O dispersion of WO3 nanoparticles without applying high potential, adding surfactants or polymers. The process is based on the redn. of WO3, which eliminates the electrostatic repulsion between the nanoparticles causing film deposition on the cathode. The reduced WO3 (HWO3) is conductive, thus it allows further film growth towards higher thickness and coverage. The electrodeposited films consist of stacked cryst. nanoparticles, which provide a highly active surface area, facilitate the penetration of electrolyte and the intercalation/deintercalation of Li+ in the nanocrystals and therefore result in outstanding electrochromic performance and stability (92% contrast, 9 s coloring and 15 s bleaching, retaining 76% contrast after 1000 coloring-bleaching cycles). The thickness, electrochromic performance and surface coverage of the films are well tuned by potential and time. This novel nano to nano electrodeposition approach based on the electrochem. redox of nano-objects can be extended to various transition metal oxide nano-objects with different sizes and shapes. [on SciFinder(R)]
Layani M, Darmawan P, Foo WL, Liu L, Kamyshny A, Mandler D, Magdassi S, Lee PS. Nanostructured electrochromic films by inkjet printing on large area and flexible transparent silver electrodes. NanoscaleNanoscale. 2014;6 (9) :4572 - 4576.Abstract
Printed electrochromic flexible films were obtained by combining transparent silver grid electrodes formed by self-assembly and inkjet printed WO3 nanoparticles. Concd. dispersions of WO3 nanoparticles were inkjet printed on transparent plastic silver grid electrodes with a high transparency of 83% in the spectral range of 400-800 nm, and a low sheet resistance in the range of 1-5 Ω sq-1. These electrodes were used for electrochromic applications for the first time. The resultant patterned nanostructured electrochromic films maintained their coloring and bleaching performance after bending of the flexible films. [on SciFinder(R)]
Liu L, Mandler D. Patterning carbon nanotubes with silane by scanning electrochemical microscopy. Electrochem. Commun.Electrochemistry Communications. 2014;48 :56 - 60.Abstract
This work reports a novel approach of patterning carbon nanotubes (CNTs) with scanning electrochem. microscopy (SECM). The concept is based on the localized cathodic current flux, which induces the pH increase on the conductive surface confined under the microelectrode. The latter facilitates the local deposition of silane sol-gel films, which embed the CNTs from the dispersion. The patterns can be tuned by deposition potential, time and scan rate of the microelectrode, as characterized by optical microscopy, SEM (SEM), energy-dispersive X-ray anal. (EDX) and profilometry. [on SciFinder(R)]
Kraus-Ophir S, Ben-Shahar Y, Banin U, Mandler D. Perpendicular orientation of anisotropic Au-tipped CdS nanorods at the air/water interface. Adv. Mater. InterfacesAdvanced Materials Interfaces. 2014;1 (1) :1300030/1 - 1300030/9.Abstract
Anisotropic CdS nanorods tipped by Au nanoparticles on one edge (Au-CdSNRs) are perpendicularly oriented at the air/water interface, whereby all the Au tips are located in the subphase, using the Langmuir-Blodgett technique. Since these nano-objects reveal light-induced charge sepn. at the semiconductor/metal interface, it is of high interest to control their organization. The orientation of these assemblies was studied in situ while compressing the Langmuir-Blodgett trough using the π-A isotherm, Brewster angle microscopy, and horizontal touch voltammetry. All these analyses clearly confirm the induced organization of the amphiphilic Au-CdS-NRs by compression of the Langmuir layer. The compressed layers are successfully transferred by the Langmuir-Schaefer method onto transmission electron microscopy grids while maintaining the preferential orientation as analyzed by TEM, SEM, STEM, and XPS. As far as can be detd., the Langmuir-Blodgett technique was not used so far for perpendicularly orienting anisotropic nano-objects. Moreover, these findings clearly demonstrate that anisotropic amphiphilic nano-objects can be treated with some similarity to the traditional amphiphilic mol. building blocks. [on SciFinder(R)]
Metoki N, Liu L, Beilis E, Eliaz N, Mandler D. Preparation and characterization of alkylphosphonic acid self-assembled monolayers on titanium alloy by chemisorption and electrochemical deposition. LangmuirLangmuir. 2014;30 (23) :6791 - 6799.Abstract
Ti-6Al-4V alloy is the most commonly used alloy for dental and orthopedic implants. In order to improve osseointegration, different surface modification methods are usually employed, including self-assembled monolayers (SAMs). This study presents an investigation of both active (electroassisted) and passive (adsorption) approaches for the modification of Ti-6Al-4V using alkylphosphonic acid. The monolayers were characterized by cyclic voltammetry, double-layer capacitance, contact angle measurements, XPS, polarization modulation IR reflection adsorption spectroscopy, electrochem. impedance spectroscopy, and corrosion potentiodynamic polarization measurements. It is shown that the electrochem. assisted monolayers, which are assembled faster, exhibit better control over surface properties, a superior degree of order, and a somewhat higher packing d. The electrosorbed SAMs also exhibit better blockage of electron transfer across the interface and thus have better corrosion resistance. [on SciFinder(R)]
Magdassi S, Mandler D, Baidossi M, Assa R, Chernin O, Binyamin Y.; 2014. Solar-radiation-absorbing formulations, application of paint, painted metal article and related apparatus.Abstract
Paint formulations having a high absorptivity with respect to solar radiation are described. The paint formulations are also thermally and mech. durable, enabling the paint formulations to be used on components in solar thermal applications where exposure to high temps. and environmental conditions may be an issue. The paint formulation can include an oxide-based pigment, an org. binder, ≥1 additives, an inorg. filler, and/or an org. solvent. The pigment can have a relatively high absorptivity with respect to light having a wavelength in the range 250-3000 nm. Curing of the paint formulation can irreversibly convert the org. binder into an inorg. binder. [on SciFinder(R)]