Network Morphologies

Pig. 1. Interpenetrating network morphology of thermoplastic elastomer where A = the crystalline domain, B = the junction of crystalline lamellae, and... 

Thermoplastic elastomeric behavior requires that the block copolymer develop a microheterogeneous two-phase network morphology. Theory predicts that microphase separation will occur at shorter block lengths as the polarity difference between the A and B blocks increases. This prediction is borne out as the block lengths required for the polyether-polyurethane, polyester-polyurethane, and polyether-polyester multiblock copolymers to exhibit thermoplastic elastomeric behavior are considerably shorter than for the styrene-diene-styrene triblock copolymers. 

An effect of network morphology is illustrated by the work of Shen and Tobolsky (ISO). They cross-linked rubbers in the presence of inert diluents such polymerizations tend to promote intramolecular chain loops rather than interchain cross-links. Their polymers had very low stress-relaxation... 

Y Cao, G Yu, AJ Heeger, and CY Yang, Efficient, fast response light-emitting electrochemical cells electroluminescent and solid electrolyte polymers with interpenetrating network morphology, Appl. Phys. Lett., 68 3218-3220, 1996. 

In accordance with these models, modul calculations for low temperature blends fall on the line of a network morphology, while all calculations for high temperature blends fall on the line of a particle/matrix morphology (Fig. 5).9... 

In the hydrated ionomer membrane, liquid-like water acts as the pore former, pore filler, and proton shuffle. The wafer disfribufion and the random network morphology of aqueous pafhways determine proton conduction at... 

Figure 6.4 shows that long-range diff usivities of water in Nafion membranes measured by QENS, Di are equal to self-diff usivities determined by PFG-NMR, Dg, at A > 10. In well-hydrated membranes, the major geometric constraints for water mobility due to the phase-segregated, random network morphology of... 

Self-consistent approaches in molecular modeling have to strike a balance of appropriate representation of the primary polymer chemistry, adequate treatment of molecular interactions, sufficient system size, and sufficient statistical sampling of structural configurations or elementary transport processes. They should account for nanoscale confinement and random network morphology and they should allow calculating thermodynamic properties and transport parameters. 

Ma WL, Yang CY, Gong X, Lee K, Heeger AJ (2005) Thermally stable, efficient polymer solar cells with nanoscale control of the interpenetrating network morphology. Adv Fund Mater 15 1617... 

All systems in the figures were cured to apparent completeness as determined by the lack of an exotherm in the DSC of the cured samples [73,101]. All variations in Tg are the consequence of (I) the extent of molecular interaction resulting from varying the (DGEBA/ODA-PMDA PAA/PMDA) ratios, (II) changes in the network morphology (crosslink density), or (III) a combination of both of these effects. 

The network morphology of the phase-separated composite material for enhanced transport and carrier generation. Absorption and mobility of charge carriers has to be maximized within the different components of the bulk heterojunction. 

Conducting polymer blends based upon polyaniline (PANI) are a new class of materials in which the percolation threshold for the onset of electrical conductivity can be reduced to volume fractions well below that required for classical percolation (16% by volume for globular conducting objects dispersed in an insulating matrix in three dimensions) [277,278], The origin of this remarkably low threshold for the onset of electrical conductivity is the self-assembled network morphology of the PANI poly blends, which forms during the course of liquid-liquid phase separation [61],... 

Figure VI-8 TEM micrographs showing the network morphology of PANI-CSA in blends with PMMA (a) f=0.5%, and (b) f=0.25%. The organization of the conducting polymer as a network of interconnected pathways varies with the concentration of PANI-...

Figure 13.2 Illustration of the network morphology of a microphase-separated triblock copolymer with the glassy end blocks in hard spherical domains bridged by the rubbery center blocks.

Conversely, a goal to store sufficient hydrogen onboard to drive 300 miles could be too high. What if the refueling network morphology for hydrogen is based on the natural gas or electricity distribution networks,... 

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