Characterization by Optical Microscopy

The radii of both orifices can be either on a micrometer or a submicrometer scale. If the device is micrometer-sized, it can be characterized by optical microscopy. The purposes of electrochemical characterization of a dual pipette are to determine the effective radii and to check that each of two barrels can be independently polarized. The radius of each orifice can be evaluated from an IT voltammogram obtained at one pipette while the second one is disconnected. After the outer surface of glass is silanized, the diffusion-limiting current to each water-filled barrel follows Eq. (1). The effective radius values calculated from that equation for both halves of the d-pipette must be close to the values found from optical microscopy. 

In their efforts to construct stimuli-responsive, supramolecular amphiphiles, Frechet et al. [126-129] reported the synthesis of a novel series of AB and ABA block copolymers via the Williamson ether synthesis (e.g., 47, Fig. 21). Polyethylene glycols (PEGs) of different lengths were used as the linear hydrophilic B block while polyaryl ether dendrons of different sizes were used as the hydro-phobic A block. These copolymers were characterized by optical microscopy,... 

Photoreceptors may be characterized by optical microscopy for layer structure and architecture. Surface defects may be characterized by atomic force microscopy. Scratch resistance can be characterized by scratching the photoreceptor surface with a stylus of known dimensions under specified loads. Brittleness measurements are... 

When the structure cannot be characterized by optical microscopy, transmission electron microscopy comes to the fore, although scanning electron microscopy and or replica techniques are also often helpful. Most of the work to date utilizes osmium tetroxide as a stain. Samples that cannot be stained by osmium tetroxide or another similar agent often cannot be studied by electron microscopy, because the phases cannot be distinguished. Sometimes, a double bond is deliberately added in small quantities during the synthesis to facilitate staining with osmium tetroxide. This is easy to do in acrylic or styrene based systems with an addition of a trace of butadiene or isoprene. 

Test bar characterization. The injection-molded test bars are characterized by optical microscopy and by differential scanning calorimetry (DSC). Light microscopy is carried out in a Zeiss Axioplan 2 equipped with an AxioCam camera. The specimens are cross-sections cut from the centers of the test bars. They are 10 p,m thick. Slicing is carried out at -70 °C using a rotary cryo-microtome Leica RM 2165. A Mettler-Toledo DSC 82 P is employed. Sample mass is 5.0 0.1 mg. The samples are studied under nitrogen flux, cooled to —100 °C and heated to 280 °C at a rate of 20K/min. 

Even smaller pipettes, down to 3nm radius, were used to measure facilitated IT kinetics [8a]. Unlike micrometer-sized pipettes, the size and shape of a nanometer-radius ITIES cannot be evaluated by optical microscopy. Thus, a thorough electrochemical characterization of nanopipettes is required. Another problem is a higher internal resistance, which increases with decreasing radius and can become as high as 100 [8a]. A... 

The in vitro trypanocidal and antitumor activities of lfr(cot)L], cot = cyclotetraene, derivatives of dithiocarbamates and xanthates, have been investigated.700 The Ir complexes were characterized by IR spectroscopy, and MO calculations (Hiickel) were performed on the ligands. Similar studies were performed on [Ir(nbr)L], nbr = norbornadiene, L = derivatives of alquil and aryl xanthates 701 and also on [Ir2(cod)2L]X2, where L = 2-hydroxystilbamidine, X = C1, N03, C104, BPh4, and [Ir(cod)L2 ]X, where L = benznidazole, R0-2516, nifurtimox, niridazole. The complex [Ir2(cod)2(2-hydroxystilbami-dine)](BPh4)2 showed the highest activity, as studied by optical microscopy of rats kidneys. 

By optical microscopy (OM), birefringent structures are observed in semicrystalline polymers, characterized by "Maltese-crosses" under crossed polars as seen in Figure 6. As these structures grow symmetrically in three dimensions... 

Table 3.1. The Tg of AlMq3 varied from about 160°C to 190°C, with no apparent dependence on the quench rate (whether from the melt or vapor) for the few samples available for examination. Because the Tg of Alq3 falls in such a close range with AlMq3, no attempt was made to characterize the miscibility of the blend by observing the change in Tg with composition. Cold crystallization peaks were visible on every sample between Tg and Tm. The melting temperature was constant for each sample at 297°C. Crystal nucleation in AlMq3 films apparently occurs homogeneously at some temperature between Tg and Tc, because even neat evaporated films exhibited a crystallization peak. No crystal nucleation was observed by optical microscopy at temperatures slightly below Tg. It is possible that some variation in the Tg and Tc temperatures observed for the sublimed films is due to small changes in the deposition rate or pressure.

The formed colloidal solutions with nanoparticles were characterized by optical absorption and photoluminescence spectroscopy for monitoring the changes in the plasmon absorption characteristics and luminescence properties, transmission electron microscopy (TEM) and X-ray diffraction (XRD) in order to analyze the final size and structure of nanoparticles. The absorption spectra of the colloids were recorded with a UV-visible spectrophotometer (CARY 500) using a 1-cm-pathlength-quartz cell for the absorption measurements. 

Reference Surface of Concrete. The AR concrete s surface, observed by optic microscopy, presents many grains in a homogeneous paste. Most the grain sizes were between 10 and 20 pm some of them are identified by Raman micro-spectroscopy as alite and belite phases (see Fig. la). The most intense peaks of alite and belite are related to the symmetrical stretching mode of the Si-0 bond in the SiO/ unit. Three peaks characterize the alite spectrum at 548, 838 and 880 cm The belite presents several peaks at 371, 416, 533, 552, 840, 853, 889, 945, 973 and 1000 cm All these wavelengths conform to those reported in literature [2,25,26]. 

Cho and Lim compared the effect of a variety of lateral substituents on the thermal behavior of peripherally octasubstituted, metal-free phthalocyanines and their copper complexes. Despite being an interesting study, the characterization of the mesophases was tentatively made by optical microscopy and thus some doubts concerning mesophase identification still persist. The results of this study are gathered in Table 8 along with some metal-free and copper complexes discussed above to allow comparison. The free base with a chiral chain exhibited a texture resembling that of the cholesteric phase, whereas that of the copper complex was not identified. Compounds substituted with chiral chains were room-temperature liquid crystals, whatever the length and number of asymmetric carbon atoms, and the columns described a helical twist. ... 

Polymer-silica nanocomposites thus prepared are characterized by electron microscopy, scattering techniques, nuclear magnetic resonance spectroscopy, etc. to determine the structiual features. In additimi, properties such as mechanical, thermal, optical, and other important physical properties are generally determined. 

Compatibilized blends of polyarylene sulfide with SEBS-g-MA have been prepared by Hisamatsu et al. (2000). Possibly an amine-terminated PPS reacts with anhydride to form a compatibilizing copolymer. Blend properties were measured as a function of MA content on SEES. Nam et al. (2003) prepared compatibilized blends of PPS with ABS-g-MA in a TSE. Blends were characterized using optical microscopy, SEM, FTIR, DMA, and heat distortion temperature. 

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