Unperturbed polymer

Hyperbranched poly(ethyl methacrylate)s prepared by the photo-initiated radical polymerization of the inimer 13 were characterized by GPC with a lightscattering detector [51]. The hydrodynamic volume and radius of gyration (i g) of the resulting hyperbranched polymers were determined by DLS and SAXS, respectively. The ratios of Rg/R are in the range of 0.75-0.84, which are comparable to the value of hard spheres (0.775) and significantly lower than that of the linear unperturbed polymer coils (1.25-1.37). The compact nature of the hyperbranched poly(ethyl methacrylate)s is demonstrated by solution properties which are different from those of the linear analogs. 

Perturbed and unperturbed polymer dimensions deduced from intrinsic viscosity measurements, according to procedures which will be discussed later, are given in Table XXXIX of Chapter XIV. The... 

Fig. 3 Self-consistent mean-field results for the density profile (normalized to unity) of a brush for different values of the interaction parameter f). In a the distance from the grafting surface is rescaled by the scahng prediction for the brush height, h, and in b it is rescaled by the unperturbed polymer radius Rq. As increases, the density profiles approach the parabolic profile (shown as dashed lines)...

The inter- and Intramolecular contributions to the entropy and energy of fusion are calculated for several linear aliphatic polyesters and polyamides assuming the fusion process consists of two Independent contributions the volume expansion (intermolecular contribution) and the increase in the conformational freedom of each polymer chain on melting (intramolecular contribution). The intramolecular entropy and energy contributions are obtained from the configurational partition function and Its temperature coefficient calculated for an isolated, unperturbed polymer chain using the RIS approximation. 

Steady-state emission and excitation spectra are measured for the dimethyl terephthalate and three polyesters in four solvents. The polymers have the repeating unit ABm, where A is -CO— C6H4— COO-, B is -(CH2—CH2—0)m- and m - 1,2,3. An RIS treatment of the unperturbed polymers identifies the conformations that should be conducive to excimer formation by nearest-neighbor aromatic rings. The population of such conformations is maximal in the polyesters in which m = 2. 

In general, to explain the observed cosolvent effects, the preferential adsorption phenomena have been invoked. Flowever few topics in the physical chemistry of polymers have evoked so many theories but so little consensus as preferential adsorption. When a polymer is dissolved in a binary solvent mixture, usually one of the solvents preferentially solvates the polymer. This solvent will then be found in a greater proportion in the proximities of the macromolecule with respect to the bulk solution composition. This variation of the solvent composition can cause interesting phenomena such as cosolvency as was discussed before, [11, 91, 92] non - cosolvency [93, 94], and some times variation of the unperturbed polymer dimensions [95,96]... 

We will begin with the structure of unperturbed polymer monolayers in the presence of a solvent and then move on to the case of two polymer grafted surfaces in the presence of a polymeric fluid, discussing... 

The chain-end functionalized polymer is a very attractive material that possesses an unperturbed polymer chain with desirable physical properties (such as melting temperature, crystallinity, glass transition temperature, melt flow, etc.) that are almost the same as those of the pure polymer. Nevertheless, the terminal reactive group at the polymer chain end has good mobility and can provide a reactive site for many applications. This includes adhesion to the substrates, reactive blending, and formation of block copolymers. 

Hory and Fox suggested that as the viscosity of a polymer solution will depend on the volume occupied by the polymer chain, it should be feasible to relate coil size and [rj]. They assumed that if the unperturbed polymer is approximated by a hydrodynamic sphere, then [Tjjg, the limiting viscosity number in a theta solvent, could be related to the square root of the molar mass by... 

If the diatomic molecules are connected to each other to form a polymer chain, we should distinguish between an external force (if any) applied to chain ends and a force at a particular bond within the chain. Because the total strain is distributed over multiple covalent bonds and torsional angles, tension in an individual bond is usually different from the externally applied force [63, 64]. Even for unperturbed polymer coils at zero external force, the average bond force is non-zero [63]. For a single chain at a zero displacement of the end-to-end vector, the bond tension was found as = 2kT/rp and viewed as the centrifugal force acting in a bond... 

When (5 ) data for an unperturbed polymer are given as a function of M, curve-fitting of eq 2.4 to them allows the parameters q and Ml to be evaluated. However, this method is not always effective, especially for relatively flexible polymers. Murakami et al. [27] showed that eq 2.4 can be approximated by... 

These blends have been used for the fabrication of luminogenic mechanochromic thin films. Which films change their emission color upon deformation. The alkyl tails influence fhe solubilify of fhe chromophores in the polymer matrix and effect different aggregation properties. Thus, the mechanochromic fluorescence color change of the blends is related to the self-assembly of the excimer-forming dye in the unperturbed polymer matrix. 

The Gaussian chain provides an exceQent description of conformations in unperturbed polymer liquids and in the glasses obtained cooling them. 

For the calculation of the form factors of unperturbed central regions of the stars, one has to take into account that (1) the central-symmetrical unperturbed polymer density profile c(r)... 

The Gaussian chain provides an excellent description of conformations in unperturbed polymer liquids and in the glasses obtained by cooling them. In real polymer products, however, the molecules often do not have the random shape of a Gaussian chain. Forces exerted on the liquid during forming cause... 

Chain stiffness and the effects of excluded volume became the dominating issue in the years between 1980 and the start of the new millennium. Percolation simulations indicated strong effects on the unperturbed polymer conformations due to excluded volume interactions [4]. With specially synthesized model substances (prepared by the Burchard group), the transition from mean-field to highly perturbed conformation was explored [5-17]. Studies in 1996 [8] on randomly branched, and in 2004 on hyperbranched polymers [8, 18-20], showed that the fractal conception could be quantitatively adjusted to the scattering behavior of linear and branched structures over the whole (/-domain and offered valuable insight into the structure in space [16]. 

End-to-end distance of unperturbed polymer chain nm 6-15 Li, T Park, K, Computational Theor. Polym.Sci., 11,133-42,2001. 

The particularly simple relationships between the average end-to-end distance of the random coil and the chain length that are derived in section 2.4 are valid under the ideal solution conditions referred to as theta conditions. The dimension of the unperturbed polymer chain is only determined by the short-range effects and the chain behaves as a phantom chain that can intersect or cross itself freely. It is important to note that these conditions are also met in the pure polymer melt, as was first suggested by Flory (the so-called Flory theorem) and as was later experimentally confirmed by small-angle neutron scattering. 

It has been experimentally shown that the second moment of the end-to-end distance unperturbed polymer chains, which only appear under so-called theta conditions, is proportional to the... 

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