Phase intercalation-induced

The helical directors in a cholesteric phase can induce optical activity for an added dye intercalated into a cholesteric phase. 

The filling control approach has even been applied to some nanophase materials. For example, the onset of metallicity has been observed in individual alkali metal-doped single-walled zigzag carbon nanotubes. Zigzag nanotubes are semiconductors with a band gap around 0.6 eV. Using tubes that are (presumably) open on each end, it has been observed that upon vapor phase intercalation of potassium into the interior of the nanotube, electrons are donated to the empty conduction band, thereby raising the Fermi level and inducing metallic behavior (Bockrath, 1999). 

The behavior of PPy I [49] is very similar to that of the short-length oligomers with predominantly localized electronic carriers [25], whereas its continuous cycling results in a further solid-state polymerization of PPy I with the final structure (PPy II), which is less prone to electronic charge localization [47,49]. This example shows that the intercalation-induced phase transition in V2O5 dominates in determining the shape of the differential capacitance curve. 

Fig. 6.2 Interactions between phospholipids, membrane proteins, and flavonoids. (a) In acidic and neutral conditions, flavonoids such as quercetin intercalate between phospholipids in the hydrophobic zone and initiate the formation of an ordered lipid phase. Flavonoids can also interact with membrane proteins, (b) In alkaline conditions, deprotonated flavonoids cover the polar head surface of phospholipids and interact with membrane proteins, (c) When phloretin replaces quercetin, the distance between the hydrocarbon chains is increased and lipids form a superordered lipid phase. Intercalation of phloretin between the polar heads of phospholipids induces micelle formation, (d) Outer and inner phospholipidic layers can be interdigitated when phospholipids are spaced by phloretin but not by quercetin (a and b). Modified from Tarahovsky et al. (2008).

Directly measuring intercalation stress in battery electrode materials is difficult because of the multiple phases of composite electrodes and also because it is usually associated with other stresses [29, 35]. In the case of cathode and anode materials, intercalation-induced stress is believed to be one of the main factors causing battery degradation, since it results in damage to reversible interaction sites and structural fatigue [14]. The active material of each electrode is usually embedded inside a binder and conductive matrix to form a porous structure as shown in Figure 26.4 (modified from [5, 6]). This combination of binder and conductive matrix provides electron conduction paths and integrates all active particles into one piece of porous composite electrode, which is then wetted by electrolyte. 

The voltage of a lithium intercalation battery varies with its state of discharge, i.e., the intercalant composition x. Subsequently more careful experiments have shown fine structure in V(x) for many intercalation system [4, 5, 7, 10] clearly observed in plots of dxIdV vs. x or V, which can be caused by a variety of physical mechanisms such as the interactions between intercalated atoms within the host or intercalation-induced stmctural phase transitions in the host. Therefore, careful measurements of dx/dV can be used a study the physics and chemistry of the intercalation process. 

However, delamination and degradation in capacity occurred in cycled samples probably due to the intercalation-induced stress in C03O4 phase. 

Ultraviolet light is routinely used for detection however, laser-induced fluorescence of labeled DNA offers better results. For example, a PCR-amplifled DNA fragment comprised of 120-400 base pairs can be separated with a resolution up to four base pairs using 1% hydroxyethylcellulose and DB-17 capillary (60 cm effective length X 0.1 mm inner diameter with 0.1 jum phase thickness). Laser-induced fluorescence detection can yield a sensitivity of about 500 pg/mL of DNA (after staining with fluorescent intercalating dye YO-PRO-1) [14]. 

There are several possible origins for the small intercalate-specific contribution. The first is suggested by the complex Fermi surface of K3 60 (16). In addition to bandwidth variations, which depend directly on the lattice parameter, the volume of the Fermi surface may be subdy different for different intercalates, or may vary with lattice parameter or pressure, or both effects could occur. Another possibility is a pressure-induced phase transition involving molecular orientations. In pure C, fiee molecular rotations freeze out at = 249 K at 1 bar, locking into specific orientations with respect to the crystal axes (17), and... 

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