Ionic networks

As one example, in thin films of Na or K salts of PS-based ionomers cast from a nonpolar solvent, THF, shear deformation is only present when the ion content is near to or above the critical ion content of about 6 mol% and the TEM scan of Fig. 3, for a sample of 8.2 mol% demonstrates this but, for a THF-cast sample of a divalent Ca-salt of an SPS ionomer, having only an ion content of 4.1 mol%, both shear deformation zones and crazes are developed upon tensile straining in contrast to only crazing for the monovalent K-salt. This is evident from the TEM scans of Fig. 5. For the Ca-salt, one sees both an unfibrillated shear deformation zone, and, within this zone, a typical fibrillated craze. The Ca-salt also develops a much more extended rubbery plateau region than Na or K salts in storage modulus versus temperature curves and this is another indication that a stronger and more stable ionic network is present when divalent ions replace monovalent ones. Still another indication that the presence of divalent counterions can enhance mechanical properties comes from... 

Classify each of the following solids as ionic, network, metallic, or molecular (a) quartz, Si02 (b) limestone, CaC03 (c) dry ice, C02 (d) sucrose, C12H22011 (e) polyethylene, a... 

The exchange of ions and solvent between a swollen ionic network and the surrounding electrolyte is represented in Fig. 136, where the fixed ion is taken to be a cation. It is apparent that the equilibrium between the swollen ionic gel and its surroundings closely resembles Donnan membrane equilibria. 

An alternative, widely used, approach to charge assisted networks is based on the exploitation of direct acid-base reactions. There are, broadly speaking, essentially two different means to obtain charge-assisted interactions, which depend on whether the network is constructed of ions of the same charge (homoionic hydrogen bonded networks) or of ions of opposite charge (hetero-ionic networks). These two limiting situations are shown in Fig. lc,d. The utilization of... 

In this investigation, you will study the properties of five different types of solids non-polar covalent, polar covalent, ionic, network, and metallic. You will be asked to identify each substance as one of the five types. In some cases, this will involve making inferences and drawing on past knowledge and experience. In others, this may involve process-of-elimination. The emphasis is on the skills and understandings you use to make your decisions. Later, you will be able to assess the validity of your decisions. 

Based on what you know about bonding, classify each solid as non-polar covalent, polar covalent, ionic, network, or metallic. Give reasons to support your decision. 

Q Vfl f Classify the following solids as ionic, network, molecular (polar or non-polar), or metallic ... 

Ding, J. F, Chuy, C. and Holdcroft, S. 2002. Solid polymer electrolytes based on ionic graft polymers Effect of graft chain length on nano-structured, ionic networks. Advanced Functional Materials 12 389-394. 

Three unknown substances were tested in order to classify them. The table above shows the results of the tests. Use Table 5.4 to classify each substance X, Y, and Z as a metallic, ionic, network, or molecular solid. 

Solid aluminum chloride and the nonvolatile aluminum fluoride exist as continuous ionic networks the chloride in the liquid and vapor state,... 

As anion-anion repulsion in a structure increases, it becomes easier to break down the ionic network in the solid and also to separate an aggregation of the ions into individual pairs. Such reasoning may be used to account for the trends in the data in Table 12-2, in which it is seen that the lithium halides and sodium iodide have abnormally low melting points and boiling points. The fluorides, for which anion-anion repulsion effects are less marked, are not listed. 

Be able to distinguish between the various intramolecular bonds covalent (polar vs. nonpolar), ionic, network covalent, hydrogen, coordinate covalent, metallic, dispersion/Van der Waals, and molecule-ion attraction. 

Herein we wish to report another approach, namely the use of the coordination complexes and bulky organosulfonate counter anions as building blocks, to generate porous ionic network which intercalates 1,10-phenanthroline or water guest molecules. The structures of adduct [Co(trien)(phen)](l,5NDS), 5 (phen)2 (H20)8 (1) and... 

Label the four substances as either ionic, network, metallic, or molecular solids. 

Ionic, network, and metallic substances tend to have high melting points. 

The topology and connectivity of the two types of domain is expected to change according the nature of the ions. Relatively small alkyl side chains form discontinuous nonpolar pockets dispersed in a percolating (continuous) ionic network. As the... 

This behavior of the mixtures of ionic liquids with molecular solvents was recently studied, experimentally and by molecular simulation, by Del Popolo et al. [45], for mixtures of [C4C1im][PF6] with naphthalene over the entire composition range. As in the previously discussed mixtures of ionic liquids with aromatics, naphthalene is able to cleave some interionic contacts, but not all of them. With compositions in which the ionic liquid is more dilute, the ionic network subsists in the shape of filaments of continuous cation-anion contacts in a medium composed mostly of the molecular fluid. If dilution is increased, then disjoint ionic clusters, down to ion pairs, will form. Some aromatic compounds are not sufficiently good solvents to the ionic liquids and cannot disrupt the ionic network, leading to an immiscibility gap (as is the case with benzene and toluene, for example, at mole fractions around 0.7-0.8 [46, 47],... 

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