Crystal disruption

The interactions among solute molecules are a reflection of their chemical structure. The manifestations of this structural influence are the physical properties associated with their intermolecular binding. As examples, the melting point reflects the ease of crystal disruption to bring about a state change. The solubility is another phenomenon derived from the structural influences on the binding of solute molecules in a crystal. 

The reader is probably familiar with a simple picture of metallic bonding in which we imagine a lattice of cations M"+ studded in a sea of delocalised electrons, smeared out over the whole crystal. This model can rationalise such properties as malleability and ductility these require that layers of atoms can slide over one another without-undue repulsion. The sea of electrons acts like a lubricating fluid to shield the M"+ ions from each other. In contrast, distortion of an ionic structure will necessarily lead to increased repulsion between ions of like charge while deformation of a molecular crystal disrupts the Van der Waals forces that hold it together. It is also easy to visualise the electrical properties of metals in... 

The oil used for mayonnaise manufacture must remain liquid even during storage at refrigerator temperatures. If some portion of the oil solidifies, the fat crystals disrupt the surface film and the emulsion breaks. The oil is usually winterized, i.e., it is held at a low temperature for 1 or 2 days and the solid fraction is removed. Polyglycerol esters may also be added to the oil to inhibit fat crystal formation to prevent this problem. 

To estimate the amount of ultrasonic energy required to run in the scale-up crystaUizer, a study was carried out measuring crystal disruption by elutriation from a glass flow unit. As shown in Table 11-5, breakage was essentially first-order with sonication power and slurry concentration. 

Lastly, let us consider the consequences of an environment that provides either little heat or too much. If too little, then the water in the BU will likely freeze. Water crystals disrupt the physical structures of BU, and the BU dies. Some BU (plants, fungi, and microbes) have developed the ability to form dry spores that can survive low temperatures for the long periods of time, and others (fish)... 

Novel poly(aryl ether ketone) copolymers with pendant 3-(tri-fluoromethyl)phenyl groups (FPAEKs) were S5mthesized by the reaction of a crystal-disrupting monomer, 3-(trifluoromethyl)phen-ylhydroquinone (FH) and a mesogenic monomer, 4,4-biphenol (BP) with l,4-bis(p-fluorobenzoyl)benzene (BF). The synthetic routes of FPAEKs are shown in Scheme 10.8. 

Ferroelectric domains are those macroscopic (greater than 20 A) regions in a solid having natural crystal polarity which is constant, but whose direction of polarity can be altered irreversibly by a practically imposable electric field. Implied in this definition is the existence within the material of a spontaneous electrical dipole moment hence the existence of piezoelectricity, and the reversing effects of applied fields hence the existence of hysteresis, and of the probability that at some temperature before complete crystal disruption the spontaneous polarization will be destroyed or directionally randomized on an atomic scale. At this temperature the dipolar instability between the decision of order or disorder will usually produce a high peak value of incremental permittivity. 

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