Pure Block Copolymers in the Solid State

Cohen and co-workers have produced a series of papers on styrene-butadiene 

Where R, = sphere radius and is the molecular weight of the domain forming block, the results obtained by Cohen et al. scale as  

Calculation of volume fractions required values of domain radius or thickness, these were determined from SANS data at intermediate Q, i.e. where A(Q) = 1, 

A sharpening of Bragg peaks is observed but no shift in position, the sharpening was interpreted as a consequence of the growth of grains within the sample wherein all unit cells were in register with each other. 

A key factor in the NIA theory is the constant value of the interfadal layer thickness at the domain-matrix boundary. There has been mudt discusaon on the existence and magnitude of an interfadal region where partial mixing of the two components takes place. Its existence has been established by positron annihalation studies whilst its magnitude is still a source of interest. Williams has proposed that this interface is unsymmetric and of considerable extent, in terms of volume fraction, whilst Krause concludes that the interphase volume fraction is very small. Mechanical and dynamical mechanical properties have been discussed , in greater or lesser detail, in terms of the interphase volume fraction and Williams has successfully 

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