Helfand

Frisch H L and Helfand E 1960 Conditions imposed by gross properties on the intermolecular potential J. Chem. Phys. 32 269... 

Helfand E and Tagami Y 1972 Theory of the interfaee between immiseible polymers J. Polym. Sc/. Polym. Lett. 9 741 Helfand E and Tagami Y 1972 J. Chem. Phys. 56 3592... 

Broseta D, Fredriekson G H, Helfand E and Leibler L 1990 Moleeular-weight effeots and polydispersity effeots at polymer-polymer interfaoes Macromolecules 23 132... 

Helfand E, Bhattaohaqee S M and Fredriokson G H 1989 Moleoular weight dependenoe of the polymer interfaoial tension and oonoentration profile J. Chem. Phys. 91 7200... 

Helfand E 1984. Dynamics of Conformational Transitions in Polymers. Science 226 647-650. 

Helfand and Tagami [75,76] introduced a model which considered the probability that a chain of polymer 1 has diffused a given distance into polymer 2 when the interactions are characterised by the Flory-Huggins interaction parameter x They predicted that at equilibrium the thickness , d c, of the interface would depend upon the interaction parameter and the mean statistical segment length, b, as follows ... 

Here, d is the interface width, which according to Helfand [12] is determined by... 

Thirdly, the multicomponent model was applied to the case of crystallization of a random A-B copolymer by Helfand and Lauritzen [127]. Their main result is that the composition of, 4 s and B s in the crystal is determined by kinetic, rather than equilibrium considerations the inclusion of excess B increases with growth rate. 

Helfand E., Block copolymer theory. I. Statistical thermodynamics of the microphases, ACS Poly. Prep., 14, 970, 1973. 

Helfand E. and Wasserman Z.R., Block copolymers theory. 6. Cyfindrical domain. Macromolecules, 13, 994, 1980. 

Our model is based on a polyethylene-like chain similar to that used by Helfand, et. al.(i) The potential function... 

This value of a is used by Helfand (15) for PS/1,4B and is based on the experiments of Rounds (24). All other values of a were obtained by scaling to this PS/1,4B value. 

Obtained using Helfand s program to search for the molecular weight at which the free energy of mixing, AG, equals zero for the case of a diblock copolymer in which M = M + M and at a weight fraction of 0.5. 

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