Macromolecule rigid

This article deals with some topics of the statistical physics of liquid-crystalline phase in the solutions of stiff chain macromolecules. These topics include the problem of the phase diagram for the liquid-crystalline transition in die solutions of completely stiff macromolecules (rigid rods) conditions of formation of the liquid-crystalline phase in the solutions ofsemiflexible macromolecules possibility of the intramolecular liquid-crystalline ordering in semiflexible macromolecules structure of intramolecular liquid crystals and dependence of die properties of the liquid-crystalline phase on the microstructure of the polymer chain. 

Conditions of Formation of the Liquid-Crystalline Phase in the Solutions of Completely Stiff Macromolecules (Rigid Rods)... 

The intention of this brief survey has been to demonstrate that besides the "classical" aspects of isotropic polymer solutions and the amorphous or partially crystalline state of polymers, a broad variety of anisotropic structures exist, which can be induced by definable primary structures of the macromolecules. Rigid rod-like macromolecules give rise to nematic or smectic organization, while amphiphilic monomer units or amphiphilic and incompatible chain segments cause ordered micellar-like aggregation in solution or bulk. The outstanding features of these systems are determined by their super-molecular structure rather than by the chemistry of the macromolecules. The anisotropic phase structures or ordered incompatible microphases offer new properties and aspects for application. 

Benoit H. Contribution a T etude de l effet Kerr presente par les solutions diluees de macromolecules rigides. Ann Phys 1951 6 561-609. 

Benoit, H. (1950). Contribution a l etude de 1 effet Kerr presente par les solutions dilutes de macromolecules rigides , Thesis, University of Strasbourg, Serie E, No. 93. 

The subject matter will frequently be concerned with situations where the fluid contains a dispersed phase that cannot be considered a component—for example, macromolecules, rigid particles, or droplets. In these cases the continuum approximation is assumed to hold within the suspending fluid and the dispersed phase. The concentration of the rigid or fluid dispersed phase will encompass both dilute and concentrated suspensions. 

If we choose the condition of infinite dilution, en N be zero since the macromolecules are far apart. We further assume that essentially there is only one conformation of the molecule/macromolecule (rigid) (alternatively all conformations have the same energy) therefore, ewjvf = 0. Further, we assume that there are no adsorptive forces between the macromolecule and the pore wall in addition, the pore wall and macromolecule are distinct and discontinuous consequently, exp(—etjjvfpA F) has the value of 1 for molecular configurations free from overlap with the wall and the value of 0 for configurations of overlap with the wall. In random-pore networks, an ensemble average of exp(—<7(f, X ), can... 

If, however, the macromolecule rigidity is negligibly small (this means that parameter 9 —> 0), and it is possible to factor the funetion root E in the following row ... 

Basic quantities and properties utilized for the characterization of macromolecules and colloidal particles are molecular mass (Al), molecular interactions (Aj), size (radius of g3uation Rg hydrodynamic radius Rh), particle scattering function (P(q)) defined by particle shape, and internal motions. Polydispersity can also be characterized by DLS. Combinations of these quantities are useful parameters to characterize maaomolecules or colloidal particles. There are a variety of monomolecular and multimolecular colloidal particles (e.g., globular proteins) flexible chain macromolecules, rigid and semifiexible rod-like macromolecules, micelles, and other self-assembled particles. We can choose suitable and efficient pathways to characterize them depending on their nature. LLS is a very powerful tool in this respect. 

Many complex systems have been spread on liquid interfaces for a variety of reasons. We begin this chapter with a discussion of the behavior of synthetic polymers at the liquid-air interface. Most of these systems are linear macromolecules however, rigid-rod polymers and more complex structures are of interest for potential optoelectronic applications. Biological macromolecules are spread at the liquid-vapor interface to fabricate sensors and other biomedical devices. In addition, the study of proteins at the air-water interface yields important information on enzymatic recognition, and membrane protein behavior. We touch on other biological systems, namely, phospholipids and cholesterol monolayers. These systems are so widely and routinely studied these days that they were also mentioned in some detail in Chapter IV. The closely related matter of bilayers and vesicles is also briefly addressed. 

There are two problems to consider when calculating 3D pharmacophores. First, unless the molecules are all completely rigid, one must take account of their conformational properties The second problem is to determine which combinations of pharmacophoric groups are common to the molecules and can be positioned in a similar orientation in space. More than one pharmacophore may be possible indeed, some algorithms can generate hundreds of possible pharmacophores, which must then be evaluated to determine which best fits the data. It is important to realise that all of these approaches to finding 3D pharmacophores assume that all of the molecules bind in a common manner to the macromolecule. 

Unsaturated polyester resins prepared by condensation polymerization constitute the largest industrial use for maleic anhydride. Typically, maleic anhydride is esterified with ethylene glycol [107-21-1] and a vinyl monomer or styrene is added along with an initiator such as a peroxide to produce a three-dimensional macromolecule with rigidity, insolubiUty, and mechanical strength. 

A large number of SAHs described in the literature combine synthetic and natural macromolecules in the network structure. The natural components are usually starch, cellulose, and their derivatives. It is assumed that introduction of rigid chains can improve mechanical properties (strength, elasticity) of SAH in the swollen state. Radical graft polymerization is one of the ways to obtain such SAH. 

Zone 8 plastics now being developed using rigid linear macromolecules rather than crystallization and cross-linking, etc. 

---