Die Makromolekulare Chemie, Theory and Simulations最新文献_第3页

Collapse of polyelectrolyte networks induced by their interaction with an oppositely charged surfactant. Theory 聚电解质网络与带相反电荷的表面活性剂相互作用引起的崩溃。理论

Die Makromolekulare Chemie, Theory and Simulations Pub Date : 1992-05-01 DOI: 10.1002/MATS.1992.040010301

A. Khokhlov, E. Kramarenko, E. Makhaeva, S. G. Starodubtzev

{"title":"Collapse of polyelectrolyte networks induced by their interaction with an oppositely charged surfactant. Theory","authors":"A. Khokhlov, E. Kramarenko, E. Makhaeva, S. G. Starodubtzev","doi":"10.1002/MATS.1992.040010301","DOIUrl":"https://doi.org/10.1002/MATS.1992.040010301","url":null,"abstract":"A very simple theory of swelling and collapse of weakly charged polyelectrolyte networks in the solution of an oppositely charged surfactant has been developed. The following contributions to the free energy were taken into account: free energy of volume interaction and of elastic deformation of the network chains, free energy connected with micelle formation and free energy of translational motion of all mobile ions in the system (translational entropy). Both the cases of a solution of charged surfactant and that of a mixed solution of charged and neutral surfactant components have been taken into account. It has been shown that the behaviour of the network depends on the total surfactant concentration in the system and corresponds to one of the three following regimes: At low concentration, micelles inside the network are not formed and the behaviour of the polymer network is similar to that of a network swelling in the solution of a lowmolecular-weight salt (regime 1). In the second regime, surfactant concentration inside the network exceeds the critical micelle concentration and micelles are formed; in this regime the network collapses because surfactant molecules, aggregated in micelles, cease to create “exerting” osmotic pressure in the network sample. In the third regime, at very high surfactant concentration, formation of additional micelles inside the network ceases, and the network dimensions coincide with those of the corresponding neutral network.","PeriodicalId":227512,"journal":{"name":"Die Makromolekulare Chemie, Theory and Simulations","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125751386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 59

Kinetics theory of anionic copolymerization with constant monomer ratio, 1. Sequence distribution 恒单体比阴离子共聚动力学理论，1。序列分布

Die Makromolekulare Chemie, Theory and Simulations Pub Date : 1992-05-01 DOI: 10.1002/MATS.1992.040010305

Xiaodong Hu, D. Yan

引用次数: 1

Molecular geometry and chain entanglement: parameters for the tube model 分子几何和链纠缠:管模型的参数

Die Makromolekulare Chemie, Theory and Simulations Pub Date : 1992-05-01 DOI: 10.1002/MATS.1992.040010302

T. He, R. Porter

{"title":"Molecular geometry and chain entanglement: parameters for the tube model","authors":"T. He, R. Porter","doi":"10.1002/MATS.1992.040010302","DOIUrl":"https://doi.org/10.1002/MATS.1992.040010302","url":null,"abstract":"The tube diameter in the reptation model is the distance between a given chain segment and its nearest segment in adjacent chains. This dimension is thus related to the cross-sectional area of polymer chains and the nearest approach among chains, without effects of thermal fluctuation and steric repulsion. Prior calculated tube diameters are much larger, about 5 times, than the actual chain cross-sectional areas. This is ascribed to the local freedom required for mutual rearrangement among neighboring chain segments. This tube diameter concept seems to us to infer a relationship to the corresponding entanglement spacing. Indeed, we report here that the critical molecular weight, M(c), for the onset of entanglements is found to be M(c) = 28 A/([R2]0/M), where A is the chain cross-sectional area and [R2]0 the mean-square end-to-end distance of a freely jointed chain of molecular weight M. The new, computed relationship between the critical number of backbone atoms for entanglement and the chain cross-sectional area of polymers, N(c) = A0,44, is concordant with the cross-sectional area of polymer chains being the parameter controlling the critical entanglement number of backbone atoms of flexible polymers.","PeriodicalId":227512,"journal":{"name":"Die Makromolekulare Chemie, Theory and Simulations","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126112738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

Fractal dimensions of polymeric phthalocynines 聚合物酞菁的分形维数

Die Makromolekulare Chemie, Theory and Simulations Pub Date : 1992-05-01 DOI: 10.1002/MATS.1992.040010307

G. Knothe

引用次数: 5

Chain linear dimensions in the surface-enriched layer of polymer mixtures 聚合物混合物表面富集层的链线性尺寸

Die Makromolekulare Chemie, Theory and Simulations Pub Date : 1992-03-01 DOI: 10.1002/MATS.1992.040010201

Jian-Sheng Wang, K. Binder

引用次数: 12

Anisotropy of local relaxation properties of macromolecules. Spin-lattice relaxation of 13C nuclei, the nuclear overhauser effect and the estimation of parameters of an equivalent ellipsoid for kinetic segments of polymer chains 大分子局部弛豫性质的各向异性。13C核的自旋晶格弛豫，核过度效应和聚合物链动力学段等效椭球的参数估计

Die Makromolekulare Chemie, Theory and Simulations Pub Date : 1900-01-01 DOI: 10.1002/MATS.1993.040020102

Y. Gotlib, I. A. Torchinski, V. Shevelev

{"title":"Anisotropy of local relaxation properties of macromolecules. Spin-lattice relaxation of 13C nuclei, the nuclear overhauser effect and the estimation of parameters of an equivalent ellipsoid for kinetic segments of polymer chains","authors":"Y. Gotlib, I. A. Torchinski, V. Shevelev","doi":"10.1002/MATS.1993.040020102","DOIUrl":"https://doi.org/10.1002/MATS.1993.040020102","url":null,"abstract":"The expressions for the functions of spectral density at different orientations of the components of the internuclear vector with respect to the chain backbone, the frequency dependences of the spin-lattice relaxation time of 13C nuclei (T1C) and the values of the nuclear Overhauser effect (NOE) were obtained for the tetrahedral lattice model of a polymer chain with three-unit kinetic elements. It was shown that peculiar features of the behavior of T1C and NOE reflect the characteristic properties of the spectra of relaxation (correlation) times for “longitudinal” and “transverse” components of the internuclear vector. It was established that in the range of relatively short times of the relaxation spectrum the dynamics of an anisotropic kinetic segment of the chain may be described with the aid of a simple model of an elongated ellipsoid of rotation with an axial ratio of about 10. It is shown that the equivalent-ellipsoid model leads to significant differences from a more specific model of chain dynamics when a broad frequency range is considered.","PeriodicalId":227512,"journal":{"name":"Die Makromolekulare Chemie, Theory and Simulations","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127045262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

A Monte‐Carlo study of ring formation during step‐growth polymerization in three dimensions 三维阶梯生长聚合过程中环形成的蒙特卡罗研究

Die Makromolekulare Chemie, Theory and Simulations Pub Date : 1900-01-01 DOI: 10.1002/MATS.1993.040020107

A. Fawcett, Richard A. W. Mee, Frederick V. McBride

引用次数: 5

A kinetic tree‐like model of non‐linear alternating copolymerization of monomers with non‐equal reactivities of functional groups and substitution effect 具有非等量官能团反应性和取代效应的单体非线性交替共聚动力学树状模型

Die Makromolekulare Chemie, Theory and Simulations Pub Date : 1900-01-01 DOI: 10.1002/MATS.1992.040010105

H. Galina, K. Kaczmarski, B. Para, B. Sanecka

引用次数: 3

Diffusion-controlled copolymerization kinetics 扩散控制共聚动力学

Die Makromolekulare Chemie, Theory and Simulations Pub Date : 1900-01-01 DOI: 10.1002/MATS.1993.040020108

I. Maxwell, Gregory T. Russell

{"title":"Diffusion-controlled copolymerization kinetics","authors":"I. Maxwell, Gregory T. Russell","doi":"10.1002/MATS.1993.040020108","DOIUrl":"https://doi.org/10.1002/MATS.1993.040020108","url":null,"abstract":"The Smoluchowski equation is used to derive equations for predicting the values of diffusion controlled propagation and termination rate coefficients in copolymerization. None of the resulting expressions are any more complicated than the analogous homopolymerization results. Diffusion controlled propagation rate coefficients in copolymerization are predicated to depend only very weakly on chain end type, and thus the propagation kinetics of high conversion copolymerizations are expected to be considerably simpler than those of low conversions. In considering termination, expressions for the rate coefficient for termination by ‘reaction diffusion’ are first of all derived. It is possible that under some conditions (for example, high conversions) these expressions describe the overall rate of termination, but in general, overall rates of termination will be determined by rates of center of mass diffusion, which are chain length dependent. For this reason the reaction diffusion results are incorporated into a more general treatment of termination in which chain end motion is both by translational and reaction diffusion; this treatment is envisaged as applying from intermediate conversions onward. Considerable effort is subsequently invested in developing simple descriptions of copolymerization in which rate coefficients (and in particular those for termination) are allowed to be chain length dependent. An important feature of this paper is that for every parameter usilized, a means of associating to it a value appropriate for a real system is discussed; in most cases this association is readily carried out.","PeriodicalId":227512,"journal":{"name":"Die Makromolekulare Chemie, Theory and Simulations","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124127384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 17

Theory of static scattering from weakly charged copolymers in solution 溶液中弱带电共聚物的静态散射理论

Die Makromolekulare Chemie, Theory and Simulations Pub Date : 1900-01-01 DOI: 10.1002/MATS.1992.040010102

M. Benmouna, T. Vilgis, J. François

引用次数: 1