A cluster model for the polymer amorphous state

Козлов, Г. В.; Novikov, V. U.

doi:10.1070/pu2001v044n07abeh000832

Cited by 33 publications

(15 citation statements)

References 138 publications

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“…Therefore it is quite reasonable to use the free energy of formation of the specified substances 0 f G ∆ to compare their relative chemical stability under standard conditions. Conclusion on the supramolecular stability values for some oils and fats is confirmed by quantitative estimates made with the approximated GibbsHelmholtz-Gladyshev equation [31].…”

Section: Thermodynamic Theory Of Agingmentioning

confidence: 75%

“…Figure 3 shows dependence of the gerontological value indicator of individual dietary oils and fats, GPG i , from their congelation temperature, T Cong . These data were obtained by calculations according to Gibbs-Helmholtz-Gladyshev Equation (2) [7]- [9] [31]. GPG i values and the corresponding T Cong values are shown in the form of large circles.…”

Section: Some Practical Recommendationsmentioning

confidence: 99%

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Thermodynamics of Aging and Heredity

Gladyshev¹

2015

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A brief review of the author's works in the sphere of thermodynamic theory of aging is presented. Particular attention is given to justification of the methods of classical and near-equilibrium "dynamic" thermodynamics used to assess the direction and extent of ontogenesis. It is noted that discovery of the law of temporal hierarchies and the substance stability principle made it possible to use quasi-equilibrium thermodynamics to describe aging of organisms and evolution of the living world. The review contains certain examples confirming thermodynamic direction of the origin of life and its development. The author states that supramolecular thermodynamics is the foundation of modern epigenetics. The review shows that the environment affects the composition and structure of the genetic apparatus as well as gene expression through the mechanisms of hierarchical thermodynamics. The author discusses the influence of "nutritive molecules" and other biological substances on tissue composition. It is noted that "nutritive molecules" can have an epigenetic influence on DNA and genetic apparatus as a whole. The author gives recommendations regarding nutrition and use of medicines from the perspective of the thermodynamic theory of aging. Though the author used simplifications and approximations when developing the thermodynamic theory of living beings' aging, the theory is in agreement with the detected correlation between changes in the specific Gibbs free energy of supramolecular structure formation and changes in the chemical composition of body tissues during aging. The author believes that hierarchical thermodynamics is the foundation of Darwinian natural selection.

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Section: Thermodynamic Theory Of Agingmentioning

confidence: 75%

Section: Some Practical Recommendationsmentioning

confidence: 99%

Thermodynamics of Aging and Heredity

Gladyshev¹

2015

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“…The assessment of the value of ∆ G im can be performed with the use of the approximate GibbsHelmholtz-Gladyshev equation [6,9,18], which can be used for the investigation of quasi-closed systems of variable composition. For the ith systems (substances) we have [6,19] and, for example, the congealing (pouring, freezing, or melting) point of the fats or oils [15,9,6].…”

Section: Thermodynamic Model Of Ontogenesis and The Aging Of Living Omentioning

confidence: 99%

The Principle of Substance Stability Is Applicable to All Levels of Organization of Living Matter

Gladyshev

2006

IJMS

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Abstract:The principle of substance stability -the feedback principle -is applicable to all biological systems. It boils down for different temporal hierarchies to the following: during the formation (self-assembly) of the most thermodynamically stable structures at the highest hierarchical level (j), e.g., the supramolecular level, in accordance with the second law, Nature spontaneously uses predominantly the (available for the given local part of the biological system) least thermodynamically stable structures belonging to a lower level, for example, the molecular level (j-1). The principle can be also applied to understructure hierarchical levels of any temporal hierarchy. It helps in understanding the causes of cancer formation and the origin of some other diseases.

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“…The microstructure of a film made with a single amorphous polymer is expected to be homogeneous, above a certain length scale. Nevertheless, a single polymer is a polydisperse mixture formed by chains of different length that, in principle, i) may be interpenetrated totally or only to a certain extent, [8][9][10][11][12][13] ii) may have preferential positions with respect to polymerair and support-polymer interfaces, [14][15][16] iii) may have different proportions of liquid-like and solid-like domains, [17][18][19] and that, even, iii) may show partially ordered domains. [20][21][22] Thus, a certain heterogeneous microstructure must be expected even in the simplest polymer system: a single polymer sample in the bulk amorphous state.…”

Section: Introductionmentioning

confidence: 99%

“…[20][21][22] Thus, a certain heterogeneous microstructure must be expected even in the simplest polymer system: a single polymer sample in the bulk amorphous state. Several models have been proposed for the amorphous polymer state [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] but currently, the most widely accepted considers that it is formed by interpenetrating random coils having unperturbed dimensions, as in θ solvents. 23 Only a few techniques give information on the microstructure of bulk amorphous polymer samples, at the molecular level.…”

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confidence: 99%

Fluorescence Lifetime Distributions of Labeled Amorphous Polymers in Bulk

Serrano¹,

Baselga²,

Piérola³

2002

Polym J

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ABSTRACT:Polystyrene, poly(methylmethacrylate), poly(cyclohexyl methacrylate) and poly(1-butylmethacrylate) were labeled with anthryl groups by copolymerization. Films of labeled polymers as well as blends of them with unlabeled polystyrene samples of different polydispersity and molecular weight, were prepared by solvent casting. The time resolved emission of anthryl groups in those films was measured by Single Photon Counting with front face excitation at the standard 30• incident angle and with much lower incident angles to photoselect chromophores on the polymer-air surface. Fluorescence decays were fitted with bimodal fluorescence lifetime distributions, which were analyzed taking into consideration some polymer characteristics and the compatibility of polymer blends. It was thus concluded that solid-like and liquid-like environments are both in the bulk and in the surface of the film although liquid-like domains are more frequent on the surface than in bulk. Polymer T g determines the position of the two modes and polydispersity justify the broadness of the modes in the fluorescence lifetime distribution. KEY WORDS Fluorescence Lifetime Distribution / Fluorescence Decay / Poly(1-butylmethacrylate) / Poly(methylmethacrylate) / Poly(cyclohexylmethacrylate) / Polystyrene / Steady state or time-resolved fluorescence measurements of chromophores added to polymers as probes or labels can yield valuable information on the structural or dynamic properties of the system. 1 Anthryl groups have been broadly employed as polymer labels due to its well known photophysical behavior as well as to its relatively small size and high fluorescence quantum yield. 2, 3 Nevertheless, it was found 4 that the chain mobility of polystyrene (PS) is slightly reduced by the steric hindrance of the anthryl group with phenyl rings and therefore, minimum proportions of labeling groups must be introduced in the polymer to preserve unmodified the macroscopic polymer characteristics. Fortunately, due to the very high sensitivity of this technique, only very low chromophore concentrations are needed, which does not disturb the system properties. But even such low concentrations still report on its environment and on processes occurring in the nanosecond time range.It was shown 2 for anthracene dissolved in PS that rigidity and dimension of the matrix free volume are related with the vibronic structure of the fluorescence spectrum. The non-radiative deactivation processes, which involve out of plane vibrational modes and intermolecular interactions, are inhibited in polymer matrices. 2 As a consequence of the probe-polymer matrix interaction the fluorescence intensity changes with temperature following and revealing polymer relaxation processes. 5 Matrix effects on the radiationless deactivation of substituted anthracenes were also observed in films of poly(methylmethacrylate) (PMMA) and they were attributed to competing intersystem crossing and very fast internal conversion. 6 For 9-methylanthracene, 7 the radiationless deactivation rate coe...

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A cluster model for the polymer amorphous state

Cited by 33 publications

References 138 publications

Thermodynamics of Aging and Heredity

Thermodynamics of Aging and Heredity

The Principle of Substance Stability Is Applicable to All Levels of Organization of Living Matter

Fluorescence Lifetime Distributions of Labeled Amorphous Polymers in Bulk

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