Viscoelastic behavior of cubic phases in block copolymer melts

Hierarchically Ordered Montmorillonite Block Copolymer Brushes

“…82 , is in close agreement with the liquid-like behavior of previously reported disordered homopolymers (G' ∝ ω 2 ). 142 The MMT grafted homopolymer on the other hand displays a terminal regime that reflects the influence of chain tethering, G' ∝ ω 0.56 . Figure 5.3b-d are rheology comparisons of MBBs to their bulk BCP counterparts.…”

“…ation of BCPs has been used in the past as a facile method for screening BCP phase behavior. 142 However, before extracting any inferences about MBB structure from rheological data it is important to establish baseline behavior of disordered materials. The easiest way to assure a disordered material is to examine free homopolymer as shown in Figure 5.3a, its terminal behavior, G' ∝ ω 1.…”

A Re-Evaluation of the Morphology of a Bicontinuous Block Copolymer−Ceramic Material

“…Even though the individual polymer blocks and aluminosilicate particles could still move within their respective domains, in this liquid crystalline state the domain topology could not readily change and the bulk material should have exhibited a solidlike response to applied stress. 30 Finally, as the number of cross-links between aluminosilicate particles increased, the PEO and PI polymer blocks would have been immobilized by the three-dimensional network of covalent bonds within the PEO/aluminosilicate domains. In this heavily cross-linked state, the response of the material to applied stress should have been similar to that of an inhomogeneous, elastic solid.…”

“…As Poisson's ratio, σ, had a modest effect on structure factors, Table 2 only reports results for σ ) 0. Crystallites in the material had a variety of orientations relative to the strain direction so each structure factor, 〈|S hkl | 2 〉, was averaged over uniaxial contractions of s ) 30% along the [ Because the major and minor domains form interpenetrating three-dimensional networks, the double gyroid (G) structure can exhibit a solidlike response to applied stress 30 even when the individual polymer blocks can move within their respective domains. During the intermediate stages of solvent casting, imposed strain could have caused relatively large changes in domain shape (but not topology) because the aluminosilicate particles and polymer chains were not fully immobilized by a network of covalent bonds within the PEO/aluminosilicate domains.…”

Elastic moduli of multiblock copolymers in the lamellar phase

“…Efforts have been made to understand the elastic properties of diblock copolymers in the lamellar phase using a variety of methods. 2,3 Progress has also been made by Tyler and 4 Morse using a method proposed by Kossuth, Morse, and 5 Bates for obtaining the linear elastic properties of the cubic phases of diblock copolymers. They study the gyroid and body-centered-cubic phases of diblocks using standard linear elasticity theory 6 and self-consistent field theory (SCFT) 7 .…”