A stable sensor for the determination of gallic acid (GA) and caffeic acid (CA) was fabricated by electrodeposition of Zn‐Al‐NO3 layered double hydroxide film on a glassy carbon electrode (LDHf/GCE). A sensitive electrochemical method was achieved for the determination of GA and CA in a phosphate buffer solution (pH 3). The differential pulse voltammetry response of the LDHf/GCE to GA has a linear concentration range from 4 µM to 600 µM with a correlation coefficient of 0.9985 and the calculated detection limit of 1.6 µM at a signal‐to‐noise ratio of 3. The differential pulse voltammetry response of the LDHf/GCE to CA has a linear concentration range from 7 µM to 180 µM with a correlation coefficient of 0.9969 and the calculated detection limit of 2.6 µM at a signal‐to‐noise ratio of 3. The constructed sensor was applied to the determination of GA in commercial green tea samples.

We present a method for the selective etching of borosilicate glass (SCHOTT Borofloat 33), in which we modify the glass with an ultrashort pulse laser and subsequent wet chemical etching. The BF33 glass is often used in microtechnology to produce sensors, actors, and fluidic chips as it can be bonded to silicon wafers by anodic bonding. The glass is irradiated and modified by circular polarized laser light with a wavelength of 1030 nm. By etching the glass with potassium hydroxide, the modified material can be removed. In this study, the selectivity was analyzed dependent on the laser parameters pulse repetition rate, pulse duration, writing speeds, and pulse energy. A selectivity up to 540 could be observed in this study. Finally, the manufacturing capabilities for three-dimensional free form shapes in BF33 are demonstrated and compared with fused silica.

Interactions for a series of aqueous dispersions of a clay, Laponite, and nonionic difunctional triblock copolymer, Pluronic L62, with two cationic dyes, crystal violet and brilliant green, are studied using UV-vis spectroscopy, dynamic light scattering (DLS), and electrophoretic mobility (EPM) to better understand the adsorption mechanisms. Different concentrations for clay, 0.1-2.0 g/L, mixed with polymer, 0.125-0.5 g/L to produce an organoclay, were tested with a fixed dye concentration, 2.0 3 10 25 mol/L. The aggregation states of the cationic dyes interacting with the clay-polymer dispersions were characterized by UV-vis absorbance. The dyes changed aggregation states from monomer to dimer and higher aggregate states upon addition to varying Laponite-polymer dispersion concentrations. DLS was used to understand the adsorbed polymer and dye interactions on the clay particle showing longer relaxation times for the largest aggregates observed from UV-vis absorbance. The EPM was used to characterize the surface charge of the clay relative to the polymer-dye interactions, which showed that the surface charge approached zero as the dyes interacted with clay-polymer dispersions. The most significant changes occurred with a reduction in light scattering intensity and longer relaxation decay at 0.1 g/L Laponite and 0.5 g/L Pluronic L62 concentrations in the presence of cationic dyes.

Modified zaccagnaite layered double hydroxide (LDH) type films were synthesized on steel substrates by pulsed electrochemical deposition from aqueous solutions. The resulting films were characterized by X-ray diffraction, scanning electron microscopy/X-ray dispersive spectroscopy, and Fourier transform infrared spectroscopy. Structural characterization indicated a pure layered double hydroxide phase; however, elemental analysis revealed that the surface of the films contained Zn:Al ratios outside the typical ranges of layered double hydroxides. Layer thickness for the deposited films ranged from approximately 0.4 to 3.0 μm. The corrosion resistance of the film was determined using potentiodynamic polarization experiments in 3.5 wt.% NaCl solution. The corrosion current density for the coatings was reduced by 82% and the corrosion potential was shifted 126 mV more positive when 5 layers of modified LDH coatings were deposited onto the steel substrates. A mechanism was proposed for the corroding reactions at the coating.

In the following work a manufacturing process for light weight structures in Fused Silica is presented. Such structures can potentially be used for mirrors to decrease the mass by simultaneously ensuring high stiffness. This talk should give the audience the possibility to assess the selective laser etching technology for mechanical structures in the field of optical mirrors.