ISSN:1022-1344    

DOI:10.1002/mats.1992.040010101

出版商:Hüthig&Wepf Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractThe static scattering properties of weakly charged copolymers in solution are investigated. The cases of symmetrical and nonsymmetrical diblocks are considered and various structure factors calculated. The electrostatic interaction is introduced via a combination of the random‐phase approximation and the Debye‐Hückel approximation. Several cases of charge distributions are considered. In particular, diblock copolymers made of neutral and charged monomers and oppositely charged monomers are considered. All the cases deal with systems in the homogeneous disordered phase where no mesophase structures or micelle formations can be obse

ISSN:1022-1344    

DOI:10.1002/mats.1992.040010102

出版商:Hüthig&Wepf Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractWe present new results on the behaviour of single chains in homo‐and copolymer blends which are beyond the rendom phase approximation (RPA). The radius of gyration of a chain in the blend was found to depend strongly on the interactions as well as the effective diffusion constant of a single chain in the blend or copolymer melt. Note that these results cannot be obtained in the original formulation of the RPA. They are based on the effective Hamiltonian of the chain in the medium. In the equation found for the self diffusion constant of a single chain,Ds, the second term is directly the value of the effective potential at zero wave vector. Thus the measurement ofDswould detect the screened potential atq= 0. Experimental verification of these results is in progres

ISSN:1022-1344    

DOI:10.1002/mats.1992.040010103

出版商:Hüthig&Wepf Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractWe examine the effect on surface‐wetting phase transitions in polymer mixtures when the degrees of polymerization of the two components are different. It has been demonstrated by Schmidt and Binder (J. Phys. (Paris)46, 1631 (1985)) that in a symmetric polymer mixture a second‐order wetting transition occurs if the wall‐polymer interactionf(ϕ0) has a negative curvaturef″(ϕ0), where ϕ0is the surface volume fraction of the polymer component preferred by the wall. We found that in an asymmetric mixture this is not necessaril

ISSN:1022-1344    

DOI:10.1002/mats.1992.040010104

出版商:Hüthig&Wepf Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractA kinetic model is presented that can be used to predict moments of size distribution of polymer species in the system where a tri‐functional monomer with groups of different reactivity (such as glycerol) reacts irreversibly with a bi‐functional monomer with no cycle formation. A Smoluchowski‐like equation is used to follow the time evolution of the size distribution of polymer molecules up to the gel point. The results are confronted with calculations made by using the statistical cascade theory. The two methods of calculations give slightly different results. The reasons for the differences are disc

ISSN:1022-1344    

DOI:10.1002/mats.1992.040010105

出版商:Hüthig&Wepf Verlag    

年代:1992

数据来源: WILEY