Topological factor concentration dependence

A dozen measurements of Dg on concentrated polymer solutions have been carried out with well-characterized polymers in solvents of different quality, with the aim of checking the concentration dependence predicted by scaling arguments (eq 2.35 for 0 solvents and eq 2.37 for good solvents) as well as the molecular weight dependence. As can be seen from Tirrell s review [2], it was evident already in 1984 that the topological factor Fg as a function of c does not follow a simple power law, while its M dependence appears to be consistent with the reptation theory over a wide range of c. However, it was... 

In systems that are impact-modified systems, it could be observed that the critical volume concentration phenomenon also depends on the properties of the matrix polymer. Publications have shown that the size of the particles of the dispersed phase and the concentration at which the so called brittlc-to-tough transition occurs, arc influenced by many factors. It is therefore not surprising that topological theories in their present fonu, which do not take into account many of these factors, cannot give any help to predict the properties of unknown systems. Recently, a phase transition ( inversion ) in polymer blending has been experimentally observed [78],... 

Linear polymer macromolecules are known to occur in various conformational and/or phase states, depending on their molecular weight, the quality of the solvent, temperature, concentration, and other factors [1]. The most trivial of these states are a random coil in an ideal (0) solvent, an impermeable coil in a good solvent, and a permeable coil. In each of these states, a macromolecular coil in solution is a fractal, i.e., a self-similar object described by the so-called fractal (Hausdorff) dimension D, which is generally unequal to its topological dimension df. The fractal dimension D of a macromolecular coil characterises the spatial distribution of its constituent elements [2]. 

As previously mentioned, successful hybridization of NPs within a liquid crystalline medium depends on several factors including NP size/concentration, chemical compatibility, topological defects and so oti. For this reason, research groups in this field started focusing on the possibility of growing NPs directly within the LC instead of using preformed particles. However, the direct synthesis of NPs in LCs generally presents several difficulties ... 

Toxicity and immunogenicity of CNTs in vivo and in vitro studies has been attributed to various factors such as number of walls, length and aspect ratio, surface area, degree of aggregation, extent of oxidation, hydrophobicity, surface topology, method of administration, dispersibility, type and degree of functionalization, and method of manufacture (which can leave catalyst residues and produce impurities). Toxicity of CNTs is also dependent on their concentration, dose, duration and method that cells or organisms are exposed to them and even the utilized dispersant to solubilize the nanotubes. 

---