Macromolecular Thermodynamics

We begin our study of macromolecular thermodynamics by discussing these three basic quantities AS, AH, and AG. Our interpretation of the change in a polymeric system is based on the change in the values of AS, AH, and AG. A change in the properties of the polymer always occurs whenever there is a change in the surroundings (environment). In later sections we discuss two more thermodynamic quantities v, the partial specific volume, and p, the chemical potential. Both are related to the behavior of polymer solutions. 

At the moment there exist no quantum chemical method which simultaneously satisfies all demands of chemists. Some special demands with respect to treatment of macromolecular systems are, the inclusion of as many as possible electrons of various atoms, the fast optimization of geometry of large molecules, and the high reliability of all data obtained. To overcome the point 4 of the disadvantages, it is necessary to include the interaction of the molecule with its surroundings by means of statistical thermodynamical calculations and to consider solvent influence. 

Macromolecular Symposia Vol.135, Dee.l998,p.295-314 POLYMER RECYCLING THERMODYNAMICS AND ECONOMICS... 

A mechanism of action describes the molecular sequence of events (covalent or non-covalent) that lead to the manifestation of a response. The complete elucidation of the reactions and interactions among and between chemicals, include very complex and varied situations including biological systems (macromolecular receptors, physical phenomena (thermodynamics of explosions) or global systems (ozone depletion). Unfortunately, this level of mechanistic detail is often unavailable but recent advances in molecular toxicology and others hazards, at the molecular level, have provided valuable information that elucidates key steps in a mechanism or mode of action. ... 

Ackers, G. (1998), Deciphering the molecular code of hemoglobin allostery , in Di Cera (Ed ), Advances in Protein Chemistry, Vol. 51, Linkage Thermodynamics of Macromolecular Interactions, Academic Press, San Diego, CA, pp. 185-253... 

Ota, N. Stroupe, C. Ferreira da Silva, I.M.S. Shah, S.A. Mares-Guia, M. Brunger, A.T., Non-Boltzmann thermodynamic integration (NBTI) for macromolecular systems relative free energy of binding of trypsin to benzamidine and benzylamine, Proteins 1999, 37, 641-653... 

Ota, N. Brunger, A.T., Overcoming barriers in macromolecular simulations non-Boltzmann thermodynamic integration, Theor. Chem. Acc. 1997, 98, 171-181... 

The first of these assumptions, generally accepted in macromolecular chemistry [1,3], is correct enough when considering the propagation reaction under copolymerization of the majority of monomers. Simple estimates reported in paper [74] support the correctness of the second assumption. As for the third one, it is true, strictly speaking, only under 0-conditions. The conformational statistics of macromolecules in a thermodynamically good solvent is known [30] to differ from the Gaussian one. Nevertheless, this distinction may hardly influence the qualitative conclusions of the simplest theory of interphase copolymerization. To which extent the account of the excluded volume of macromolecules will affect quantitative results of this theory, may be revealed exclusively by computer simulations. 

Researchers have accumulated a large body of thermodynamic and kinetic data to assess these effects, and many of these results are included in the tables of reference 101. Qualitatively, one concludes that for small molecule Gd(III) complexes—those of molecular weight<1000 Da—a high relaxivity, measured in mM 1 s 1, will approach an upper limit of 5 mM-1s-1. Some data are collected in Table 7.3. Newer macromolecular conjugate-Gd(III) complex systems, also discussed below, may approach relaxivities five to six times larger per Gd(III) ion. 

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