Honeycomb-like structures

At r = 0.5 (Fig. 9b), the most interesting and novel morphology can be observed. This morphology can be described as follows. The P4VP cores of the microspheres form a regular structure, and a P4VP bilayer surrounds each microsphere with a honeycomb-like structure, similar to a cell wall, as the number of the microsphere surrounded by the P4VP wall ( T) was 1.08. Similar structures have been observed for ABC triblock copolymers [39]. Our honeycomb-like novel structure, however, is different from that of the ABC triblock co-... 

The chain arrangement of this morphology was schematically proposed as in Fig. 10. The cell of the microsphere has a hexagonal surface, and the AB diblock copolymers form a bilayer between the microspheres. From this schematic arrangement, the optimal blend ratio of the AB block copolymer in this system was calculated as 0.46. This value was very close to the blend ratio of the AB type block copolymer 0.5 at which the blend showed the hexagonal packed honeycomb-like structure. 

D Oxychloride Frameworks with a Honeycomb-like Structure... 

Activated carbon, activated charcoal. A form of carbon that has (a) a porous or honeycomb-like structure and therefore a large surface area and (b) high adsorbdvity (certain molecules stick to it). Used to strip out impurities or extract selected compounds. 

N—H 0 hydrogen bonds and are interlinked by the syrc-N—H 0 hydrogen bonds. (Reprinted from [9] with permission from A AAS) (b) Van der Waals cross-section of the cavity in the urea channel compared with the size of /3-octane (left), benzene (top), 3-methylheptane (right) and 2,2,4-trimethylpentane (bottom), (c) chemical structures of urea and thiourea, (d) packing of urea channels to give the honeycomb-like structure of hexagonal urea. 

Both materials used as hosts are distinguished by different geometries and pore dimensions, that is, the zeolite Y is constituted of spherical supercages of 1.3 nm of diameter tetrahedrally interconnected through 0.74 nm windows. On the other hand, the structural characteristics of MCM-41 have been expressed in terms of a honeycomb-like structure with a pore diameter of 3.5 nm and a wall thickness of ca. 1.1 nm [67], The Ni-Y zeolite was prepared by Ni(N03)2 exchange of the NaY sample, and the CBV100 was provided by the PQ Corporation Malvern, PA, USA. [67],... 

III. PHENOMENOLOGY OF A FORMATION OF A HONEYCOMB-LIKE STRUCTURE DURING COPPER ELECTRODEPOSITION... 

The honeycomb-like structure was formed from solution (I) (Fig. 25a). 

The copper deposits obtained from 0.075 MC11SO4 in O.5OMH2SO4 at an overpotential of 1,000 mV with the quantities of electricity of 2.5 and 20mAh cm-2 are shown in Fig. 26, from which it can be seen that honeycomb-like structures were formed by electrodepositions from this solution. 

On the basis of the presented analysis of the electrodeposition processes at an overpotential of 1,000 mV (Figs. 26-28), it is obvious that increasing the concentration of Cu(II) ions leads to a change in the shape of the holes from those forming a honeycomb-like structure to dish-like holes. 

Anyway, there are two effects of hydrogen evolution on copper electrodeposition leading to the formation of the honeycomb-like structures. The first effect is a stirring of the solution in the nearelectrode layer caused by a vigorous hydrogen evolution leading to the decrease of the diffusion layer thickness and the increase of the limiting diffusion current density.10 The second effect concerns... 

Dish-like holes were formed from the more concentrated solution (0.60 MCUSO4 in 0.50 M H2SO4), accompanied by a considerably lower quantity of evolved hydrogen (jjav(I h) = 4.6%) than was the case with the holes forming a honeycomb-like structure (0.075 M and 0.15 M Q1SO4 in 0.50 M H2S04). 

Morphologies of copper deposits obtained at an overpotential of 1,000 mV from these copper solutions are shown in Figs. 35-37. The honeycomb-like structure was formed by the electrodeposition from 0.15 MCUSO4 in 1.0MH2SC>4(Fig.35). From Fig. 35 it can be seen that holes were lined up in parallel rows. The average diameter of formed holes was 50 pm, while the number of formed holes was 71/mm2 surface area of the copper electrode. 

Hence, increase the temperature led to a redistribution of evolved hydrogen from those creating a honeycomb-like structure (holes formed due to the attachment of hydrogen bubbles with cauliflower-like agglomerates of copper grains between them) to those making a copper structure with the dominant presence of cauliflower-like forms and irregular channels between them. 

Analysis of Deposition Conditions with the Aspect of the Honeycomb-like Structure Formation... 

It is obvious that the honeycomb-like structures can be considered as possible electrodes in electrochemical devices such as fuel cells and sensors due to their very open and porous structure. Analysis of the effect of different parameters of electrolysis given in this section enables to be systematized electrodeposition conditions leading to the formation of this structure type. 

The acceleration of electrochemical processes through the increase of concentration of Cu(II) ions above 0.15M CuSC>4 (in 0.50 M H2SO4) showed an unfavorable effect to the formation of the honeycomb-like structure due to the formation of dish-like holes with the higher concentrations of Cu(II) ions.58... 

The number of craters or holes forming the honeycomb-like structure increased rapidly with the quantity of evolved hydrogen, as can be seen from Fig. 42 which shows the dependence of the number of holes or craters formed due to the attachment of hydrogen bubbles on the average current efficiency of hydrogen evolution. 

The electrode surface roughness at low level of coarseness can be increased in some different ways other than dendrites (spongy-like deposit,33 honeycomb-like structure,76,77 pyramid-like deposit,83 etc.) on the microscale. The properties of electrodeposits on nanoscale should be also taken into consideration.84,85 Further investigation will show which one of them is the best for this purpose. This chapter is written in order to initiate it. 

Tanev et al. have reported the synthesis of mesoporous materials via a route which involves self-assembly between neutral primary amines and neutral inorganic framework precursors.12 The regularity of the pore structure in these materials has been illustrated by lattice images which show a honeycomb like structure. The system of channels of these molecular sieves produces solids with very high internal surface area and pore volume. This fact combined with the possibility of generating active sites within the channels produces a very unique type of acid catalyst. In the case of transition metal substituted M41S, the principal interest lies in their potential as oxidation catalysts, especially Ti and V substituted MCM and HMS type materials, and more recently synthesised large pore materials.13... 

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