Network thermodynamics transport processes

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. 

The first question was answered by Network Thermodynamics (e.g. Oster et al., 1973 Schnakenberg, 1977 Peusner, 1985) adopting the bond graph technique. This approach benefits from the formal correspondence between certain interpretations of nonequilibrium thermodynamics and of electrical network theory. Adopting the notions of chemical impedance , chemical capacity and chemical inductance , chemical reactions as well transport processes can be represented by networks obeying KirchhofFs current and voltage laws. 

At these assumptions and simplifications the thermodynamic network analysis (TNA) [90] can be applied to analyze LM transport. Certainly in the case of a real specific system, the detailed mechanism of reaction-diffusion interfacial phenomena should be taken into account as far as possible. The above assumptions allow maintaining a concept of a homogeneous reaction. Any universal model does not exist, and in the description of a real membrane process the accessible knowledge concerning the specific interfacial processes should be taken into account. The model presented can be regarded as a simplified example only. 

Most practical zeolitic adsorbents are used in a pellet form (with or without binders) where a network of meso-macro pores provide the access of the gases to the adsorption sites (inside the micropores of crystalline zeolites). The zeolite crystal and the pellet radii are typically in the range of 0.5-2.0 pm and 0.5-2.0 mm, respectively. Consequently, the kinetics of ad(de)sorption of Nz and Oz are often controlled by the transport of these gases through the mesoporous network, and the ad(de)sorption kinetic (Knudsen, molecular and Poiseuille flow) time constants are large (>0.5 seconds 1). Thus, the kinetics of ad(de)sorption processes may not be critical. The thermodynamic adsorptive properties (a,b) and the desorption characteristics (c) under local equilibrium conditions often determine the separation performance of a zeolite. 

Ultrasound-Assisted Reconstruction of Fiber Networks Besides thermodynamic control and additive-mediated formation of fiber networks, exposure of external fields in the molecular self-assembly process is another promising strategy for creating innovative supramolecular materials and systems with dynamically controlled property/functionality. The substantial interest in stimuli-responsive assembly of small molecules shown in recent years has led to the birth of new interdisciplinary research areas in the development of supramolecular materials with dynamically controlled fluidity, viscoelasticity, solvent volatility, optical transmission, ion transport, wettability, and other physical properties [6-8,11]. 

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