Lower critical disorde-order transition

Oscillatory Shear Rheometry of Microsphase-Separated Block Copolymers Exhibiting Lower Critical Disorder-Order Transition Behavior... 

LCDOT Lower critical disorder-order transition... 

Reactive compatibilization can also be accomplished by co-vulcanization at the interface of the component particles resulting in obliteration of phase boundary. For example, when cA-polybutadiene is blended with SBR (23.5% styrene), the two glass transition temperatures merge into one after vulcanization. Co-vulcanization may take place in two steps, namely generation of a block or graft copolymer during vulcanization at the phase interface and compatibilization of the components by thickening of the interface. However, this can only happen if the temperature of co-vulcanization is above the order-disorder transition and is between the upper and lower critical solution temperature (LCST) of the blend [20]. 

The responsive behavior of ELRs has been defined as their ability to respond to external stimuli. This property is based on a molecular transition of the polymer chain in the presence of water at a temperature above a certain level, known as the Inverse Temperature Transition (ITT). This transition, whieh shares most of the properties of the lower critical solution temperature (LCST), although it also differs in some respects, particularly as regards the ordered state of the folded state, is clearly relevant for the application of new peptide-based polymers as molecular devices and biomaterials. Below a specific transition temperature (T,), the free polymer chains remain as disordered, random coils [20] that are fully hydrated in aqueous solution, mainly by hydrophobic hydration. This hydration is characterized by ordered, clathrate-like water structures somewhat similar to those described for crystalline gas hydrates [21, 22], although somewhat more heterogeneous and of varying perfection and stability [23], surrounding the apolar... 

Figure 5.1 shows that the pressure ceases to monotonically increase. The break point in the curve corresponds to a transition in the structural order. Instead of all the particles being distributed in a relatively disordered configuration, regions of the box begin to order in an fee structure. The lower bound occurs when 49.4% of the volume is particles. This coexistence region extends along the plateau until at a critical volume the system is entirely composed of particles with an fee order where the particles occupy 54.5% of the box volume. This is the... 

The phase behavior of a synthetic lecithin, dipalmitoyllecithin, as analyzed by Chapman and co-workers (5), is diagrammed in Figure 3. The main features are the same as in the phase diagram of egg lecithin a mixture of numerous homologs. As a consequence of the variation in fatty acid chain length, the chain melting point is lowered which means that the critical temperature for formation of liquid crystalline phases is reduced. This temperature is about 42 °C for dipalmitoyllecithin, and, if the lamellar liquid crystal is cooled below this temperature, a so-called gel phase is formed. The hydrocarbon chains in the lipid bilayers of this phase are extended, and they can be regarded as crystalline. The gel phase and the transitions between ordered and disordered chains are considered separately. 

At lower temperatures, the spin concentration of PMQ4 increased as temperature decreased as illustrated in Figure 10. The reason for this is presently unknown. One possibility is that a phase transition from magnetic disorder to order could occur at a critical temperature, T<,. Three determinations of spin concentration versus temperature for PMQ4 were carried out with reproducible results within experimental error. The data was fitted using Equation 2. 

---