Titanium hydride nanoparticles and nanoinks for aerosol jet printed electronics.

Conductive inks commonly rely on oxidation-resistant metallic nanoparticles such as gold, silver, copper, and nickel. The criterion of air stability limits the scope of material properties attainable in printed electronic devices. Here we present an alternative approach based on air-stable nanoscale metal hydrides.

The advent of membrane-less zinc-anode aqueous batteries with lithium battery-like voltage.

Zinc (Zn)-anode batteries, although safe and non-flammable, are precluded from promising applications because of their low voltage (<2 V) and poor rechargeability. Here, we report the fabrication of rechargeable membrane-less Zn-anode batteries with high voltage properties (2.5 to 3.

Hydroxyl Conducting Hydrogels Enable Low-Maintenance Commercially Sized Rechargeable Zn-MnO Batteries for Use in Solar Microgrids.

Zinc (Zn)-manganese dioxide (MnO) rechargeable batteries have attracted research interest because of high specific theoretical capacity as well as being environmentally friendly, intrinsically safe and low-cost. Liquid electrolytes, such as potassium hydroxide, are historically used in these batteries; however, many failure mechanisms of the Zn-MnO battery chemistry result from the use of liquid electrolytes, including the formation of electrochemically inert phases such as hetaerolite (ZnMnO) and the promotion of shape change of the Zn electrode. This manuscript reports on the fundamental and commercial results of gel electrolytes for use in rechargeable Zn-MnO batteries as an alternative to liquid electrolytes.

Slot-die-coating operability windows for polymer electrolyte membrane fuel cell cathode catalyst layers.

Roll-to-roll (R2R) slot-die coating of polymer electrolyte membrane fuel cell (PEMFC) catalyst layers represents a scalable deposition method for producing 10-20 m·min of catalyst-coated gas diffusion layers (GDLs). This high-throughput production technique will help lower the cost of PEMFC catalyst layers. The uniformity of the wet layer applied by slot die deposition is affected by process parameters such as substrate speed, vacuum pressure applied at the upstream meniscus, gap between the slot die lips and substrate, ink rheology, and other ink and substrate properties.

Synthesis, Characterization, and Nanomaterials Generated from 6,6'-(((2-Hydroxyethyl)azanediyl)bis(methylene))bis(2,4-di- tert-butylphenol) Modified Group 4 Metal Alkoxides.

The impact on the morphology nanoceramic materials generated from group 4 metal alkoxides ([M(OR)]) and the same precursors modified by 6,6'-(((2-hydroxyethyl)azanediyl)bis(methylene))bis(2,4-di- tert-butylphenol) (referred to as H-AM-DBP (1)) was explored. The products isolated from the 1:1 stoichiometric reaction of a series of [M(OR)] where M = Ti, Zr, or Hf; OR = OCH(CH)(OPr ); OC(CH)(OBu ); OCHC(CH)(ONep) with H-AM-DBP proved, by single crystal X-ray diffraction, to be [(ONep)Ti( k( O,O',O'',N)-AM-DBP)] (2), [(OR)M(μ( O)- k( O',O'',N)-AM-DBP)] [M = Zr: OR = OPr , 3·tol; OBu , 4·tol; ONep, 5·tol; M = Hf: OR = OBu , 6·tol; ONep, 7·tol]. The product from each system led to a tetradentate AM-DBP ligand and retention of a parent alkoxide ligand.

In situ characterization of silver nanoparticle synthesis in maltodextrin supramolecular structures.

The use of maltodextrin supramolecular structures (MD SMS) as a reducing agent and colloidal stabilizing agent for the synthesis of Ag nanoparticles (Ag NPs) identified three key points. First, the maltodextrin (MD) solutions are effective in the formation of well-dispersed Ag NPs utilizing alkaline solution conditions, with the resulting Ag NPs ranging in size from 5 to 50 nm diameter. Second, in situ characterization by Raman spectroscopy and small angle X-ray scattering (SAXS) are consistent with initial nucleation of Ag NPs within the MD SMS up to a critical size of ca.

Large area mosaic films of graphene-titania: self-assembly at the liquid-air interface and photo-responsive behavior.

Photo-responsive graphene-titania composite nanofilms were formed via evaporative induced self-assembly at the air-liquid interface from the UV-photo-reduction of titania-graphene oxide colloidal solutions.

Photon control of liquid motion on reversibly photoresponsive surfaces.

The movement of a liquid droplet on a flat surface functionalized with a photochromic azobenzene may be driven by the irradiation of spatially distinct areas of the drop with different UV and visible light fluxes to create a gradient in the surface tension. In order to better understand and control this phenomenon, we have measured the wetting characteristics of these surfaces for a variety of liquids after UV and visible light irradiation. The results are used to approximate the components of the azobenzene surface energy under UV and visible light using the van Oss-Chaudhury-Good equation.

Photophysical effects between spirobenzopyran-methyl methacrylate-functionalized colloidal particles.

Colloidal particles were derivatized with end-grafted polymethylmethacrylate polymer brushes containing varying concentrations of spirobenzopyran photochromic molecules. The polymers were grown from initiator-functionalized silica particles by an atom-transfer radical polymerization (ATRP). These core-shell colloids formed stable suspensions in toluene with the spirobenzopyran in its closed, nonpolar form.

Patterned colloid assembly by grafted photochromic polymer layers.

Quartz surfaces and colloidal silica particles were derivatized with a poly(methyl methacrylate) copolymer containing spirobenzopyran (SP) photochromic molecules in the pendant groups at a concentration of 20 mol %. Two-photon near-IR excitation (approximately 780 nm) was then used to create chemically distinct patterns on the modified surfaces through a photochromic process of SP transformation to the zwitterionic merocyanine (MC) isomer. The derivatized colloids were approximately 10 times more likely to adsorb onto the photoswitched, MC regions.

Rheological properties of nanopowder alumina coated with adsorbed fatty acids.

The rheological properties of a nanosized alumina powder coated with fatty acid steric stabilizers of varying chain length were investigated. The storage and loss moduli of the complex modulus were measured to characterize the behavior of the flocculated systems. As chain length increased, there was a transition from an elastic response to fluid behavior.

Dispersion properties of an alumina nanopowder using molecular, polyelectrolyte, and steric stabilization.

A commercial alumina nanopowder was characterized and its dispersion was studied using electrostatic, electrosteric, and steric surfactants. Citric acid was used as the electrosteric dispersant, ammonium polymethacrylic acid (Darvan C) as the electrosteric dispersant, and Hypermer KD-1 in alpha-terpineol as a purely steric system. Phase stability in water was examined by X-ray diffraction, and the surface chemistry was characterized by zeta potential and isoelectric points.

Cation-induced collapse of low-molecular-weight polyacrylic acid in the dispersion of barium titanate.

Observations on the steric layers formed by the adsorption of low-molecular-weight polyacrylic acid (PAA) were taken using the colloidal probe method in an atomic force microscope. The effects of divalent barium ions and of monovalent potassium ions at varying concentrations were observed on the repulsive interaction profiles. High ionic concentrations screened double-layer forces to small distances, whereby the acting forces were reduced to steric interactions.