Effect of chain topology

The primary length scale in polymer solutions, even at elevated polymer concentrations, is apparently the size of the complete chain. In some sense, this residt should have been expected. The beads on a polymer chain may move in all sorts of different ways, but they are obliged to stay connected to each other, guaranteeing that there is a significant length scale corresponding to the volume of space (partially) occupied by the beads of a polymer chain. 

As discussed in Section 9.10, an additional very slow mode is observed in hydroxypropylcellulose water, even in the absence of probe particles. The mode appears to correspond to the diffusion of long-lived local vitrified regions through the solution. The regions, which are correlated with the solutionlike-meltlike transition, appear to be substantially larger in spatial extent than a single polymer chain. 

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Odell and Keller first proposed a bead-rod model to explain the degradation of an isolated polymer chain in QSSF [27,28]. This is also the basis for further discussing the effect of chain topology in the following sections. The key assumptions are ... 

Shaffer s bond fluctuation model (Shaffer, J. S., 1994. Effects of chain topology on polymer dynamics—Bulk melts, J. Chem. Phys., 101 4205 13). Polymers are grown as random walks on a simple cubic lattice, subjected to the excluded volume, chain connectivity, and chain uncrossability constraints described in the text. 

Shaffer, J. S., 1994. Effects of chain topology on polymer dynamics— Bulk melts, /. Chem. Phys., 101 4205-4213. 

Paknla, Tadensz, Koynov Kaloian, Boerner Hans, et al. Effect of chain topology on the selforganization and the mechanical properties of poly(n-bntyl acrylate)-b-polystyrene blockcopolymers. Polymer. 52 no. 12 (2011) 2576-2583. 

Cherdhirankom T, Floudas G, Butt H-J, Koynov K (2009) Effects of chain topology on the tracer diffusion in star polyisoprenes. Macromolecules 42 9183-9189... 

A combination of Eqs. 5.1 and 5.6 leads to v = 3y — 1 and = 3y>. Inputting our experimentally determined values of y and directly measured values (0.39 0.01 and 0.31 0.01) from the viscosity measurements, which cross-examines and validates our previous LLS data and current viscosity results. It is worth-noting that in comparison with LLS, viscosity is more sensitive and much easier to be measured in characterizing the effect of chain topology and conformation, such as the branching degree, because LLS measures the hydrodynamic size, while viscosity detects the hydrodynamic volume that is a cubic of the chain size. 

In aqueous emulsion polymerization, amphiphilic polymers are widely used as polymeric surfactants to stabilize the latex particles, where the hydrophobic blocks can anchor on the particle surface while the hydrophilic blocks extend into the water phase and create a hydrophilic shell [47, 49-52]. Therefore, PS-PAA-PS and HB-(PAA)47-g-(PS)48 copolymers were further used as polymeric surfactants to explore the effect of chain topology on the emulsifying efficiency. The characterization results of solid contents (t), latex particle sizes ( R)) and numbers (A p) are summarized in Table 5.2, Figs. 5.29 and 5.30, where the average particle diameters were carefully determined by DLS at pH 3.2 to ensure the full collapse... 

Gitsas, A., Floudas, G., Mondeshki, M. et al. (2008a) Effect of chain topology on the self-organization and dynamics of block copolypeptides From diblock copolymers to stars. Biomacromolecules, 9,1959-1966. 

This section makes a qualitative and quantitative comparison of the above results on various polymer solvent systems, looking for systematic features of the phenomenology. The functional form of r](c, M), effects of chain topology and solvent quality, and the quantitative behavior of the fitting parameters are examined. 

Hikosaka presented a chain sliding diffusion theory and formulated the topological nature in nucleation theory [14,15]. We will define chain sliding diffusion as self-diffusion of a polymer chain molecule along its chain axis in some anisotropic potential field as seen within a nucleus, a crystal or the interface between the crystalline and the isotropic phases . The terminology of diffusion derives from the effect of chain sliding diffusion, which could be successfully formulated as a diffusion coefficient in our kinetic theory. 

A new, valuable type of experiment are computer simulations of network properties. Computer simulations are well established both in equilibrium and non-equilibrium physics of systems of linear chains and have been used for the study of networks and melts. The effect of the topological constraints on the stress-strain behaviour of tetrafunctional networks with a regular structure has been investigated by Elyashevich and Remeev using Monte Carlo methods to generate Marko-... 

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