Macromolecules dimensions formation

Thus, at T > T3, the long semiflexible macromolecule is in the coil state while at T < T3 it is in the globular state. Consequently, the temperature T3, which is determined by Eq. (3.7), is the temperature of the coil-globule transition for the long freely jointed macromolecule (see Fig. 6). It is clear that this transition is the first order phase transition with a considerable bound of the coil dimensions, it leads simultaneously to the transformation of the coil into the globule and to the formation of the liquid-crystalline ordering in the globule. 

In the case of heterogeneous network formation, one can sometimes observe two critical gel points, the first one corresponds to the appearances of the infinite macromolecules in the form of microgel particles of colloid The second macroscopic gel point correlates with the rheological transition from a solution to the state of a gel, when the system as a whole losses the possibility to flow and is converted into a single three-dimension macromolecules. 

One of the major motivations for the study of nano-aggregate formation, either in bulk or in solution, is because it provides an opportunity to construct macromolecular objects with dimensions significantly larger than molecular dimensions, and therefore would pave the way to further organize them well into the macroscopic domain. Thus, this serves as a step-wise approach to organizing macromolecules in the bulk phase, with a control over the molecular organization at each step along the way. The fixation of the mushroom-shaped supramolecular ag-... 

The influence of macromolecules formation mechanism on their dimension has been shown particularly clearly on the example of lignin pol5rmers [29, 30], The bios5mthesis reaUzation in vitro dehydropolymers by two methods (end-wise-pol5nnerization and bulk-polymerization) gives lignin s with dimension Z) =2.62 0.27 and 1.66 0.16, respectively. Thus, the adduced above values indicate unequivocally on synthesis realization by the mechanisms P-Cl and Cl-Cl, respectively, for the same polymer at the S5mthesis conditions variation. 

Dendrimers are multibranched macromolecules with nanometer-scale dimensions. They are considered to be ideal candidates for biological applications. Such macromolecules are monodisperse or closely monodisperse and they give reliable drug or gene deliveries compared to other polymers. Dendrimers are then used for the formation of labelled-ligand bioconjugates [225]. 

As a result of their higher dimensions, comparatively with low molecular weight compounds, no macromolecules as such will be found in the nodes of the crystalline network, but only their constituting atoms. The larger dimensions of the chains reduce drastically the mobility of their individual atoms and, consequently, the speed at which they move for getting their position in the crystal. This explains the polymers poorer and only partial crystallization, imperfect crystal formation, comparatively with the low molecular weight compounds. 

The formation of entanglements between the macromolecules of a polymer melt is influenced by the dimensions and the structure of the chain. 

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