Copolymer systems surface morphology

In this section of our review, we shall discuss the morphological aspects and structure-property relationships of a few specific copolymeric systems which we think will represent the general features of siloxane containing multiphase copolymers. More detailed discussions about the properties of each copolymer system may be found in the references cited during our review of the copolymer preparation methods. On the other hand an in-depth discussion of the interesting surface morphology and the resultant surface properties of the siloxane containing copolymers and blends will be provided. 

In the Current State of the Art we will review some of the recent SANS and reflectivity data from ISIS, which also serve to point to future directions and opportunities. Recent reflectivity measurements, on the adsorption of polymers and polymer/surfactant mixtures at interfaces, surface ordering in block copolymer systems, time dependent inter-diffusion at polymer-polymer interfaces, and the contribution of capillary waves to interfacial widths, will be described. The use of SANS to investigate the dynamic of trans-esterification of polyester blends, the deformation of copolymers with novel morphologies, and the use of diffraction techniques to determine the structure of polymeric electrolytes, will be presented. 

Next we consider the effect of the block copolymer composition /= NfJN on the ordered morphology. In the limit of very strong segregation, that is, zero interface width, the natural idea is to let the stable ordered phase correspond to the phase with the minimal interface surface. To illustrate this principle and to obtain a semiquantitative estimate of the values of/for which the transitions between the three classical stmctures occur, we consider an LxLxL volume of the self-assembled diblock copolymer system. The ordered states that will be compared are the lamellar phase, a square lattice of cylinders, and spheres on a simple cubic (SC) lattice. L is the periodicity length scale of the layers, the square, and the cubic lattice (Figure 19). The LxLxL volirme element contains one cylinder resp. one sphere. Volirme conservation (Figure 20), therefore, requires fL = 7tRcL = 4n/SRs, where Rc and Rs are the radii of the cylinder and the sphere, respectively. 

D visualization of bicontinuous morphologies in block copolymer systems has been achieved [26-27] by TEMT (see Sect 2.2). This technique affords the real-space structural analysis of complex nanoscale morphologies without a priori synunetry or surface assumptions [97]. Application of numerical methods developed [39, 98] to measure interfacial curvatures from 3D LSCM images of SD polymer blends (see Sects. 3.2.3 and 4.3.3) to a TEMT reconstruction of the G morphology yields the first experimental measurements of interfacial curvature distributions, as well as (H) and an, in a complex block copolymer nanostructure. 

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