Deformation and orientation behavior of polystyrene-b-polybutadiene-b-poly(methyl methacrylate) triblock terpolymers: Influence of polybutadiene microstructures and the molar masses

Abstract

Morphological changes caused by deformation and orientation of different domains of polystyrene-b-polybutadiene-b-poly(methyl methacrylate),SBM, triblock terpolymers were investigated using in-situ small angle X-ray scattering (SAXS), tensile testing, and transmission electron microscopy (TEM). Two sets of SBM triblock terpolymers with similar weight fractions of the three blocks were studied. The two sets differ in terms of their molecular weights. Each set contained two SBM differing in their polybutadiene isomers (1,2-and 1,4-B). Results showed that for 1,2-B based SBMs polybutadiene forms cylindrical domains which coalesce in the glassy lamellar matrix of the two glassy outer blocks whereas the lower molar mass 1,4-B based SBM forms mixed S/M and the higher one forms well segregated long range ordered lamellae. These morphological differences indicate that the deformation and the orientation behavior of the polymers' domains differ. In 1,2-B based SBMs yielding at high stresses was followed by a stress drop after the yield point. The other polymer type showed homogeneous deformation of the lamellar domains at their yield point. 2D-SAXS during deformation of the triblock terpolymers showed an anisotropic deformation pattern in the 1,2-B SBMs, whereas four point SAXS patterns were found for the 1,4-B SBMs. Further studies showed that the fragmented lamellar planes of the lower molar mass 1,2-SBM oriented randomly whereas the orientation of the lamellar planes of the higher molar mass 1,2-B SBM was parallel to the strain direction. The alignment of the lamellar planes of 1,4-B SBMs were randomly distributed in the unstretched state.

Hierarchical Micelles via Polyphilic Interactions: Hydrogen-Bonded Supramolecular Dendrons and Double Immiscible Polymers

“…We here report the supramolecular blending of a polymer A with another polymer C leading to the newly formed noncovalently linked polymer AB′C, where the middle segment B′ represents a supramolecular linker, segregating from both the A- and the C-block of the molecule (see Figure ). Although covalently linked ABC triblock terpolymers are the prototype of a polyphilic system well-known to microphase separate via, for example, hydrophilic/fluorophilic/hydrophobic interactions, − the inclusion of directed supramolecular interactions as part of a polyphilic segregation has not been addressed yet. The formation of nanostructured compartments of supramolecular polymers driven by noncovalent forces thus presents a novel concept toward multicompartment micelles. − …”

Nanostructure development in polystyrene‐b‐polybutadiene‐b‐poly(methyl methacrylate) (SBM) thin films by atomic force microscopy: Effect of copolymer composition and solvent

“…They concluded that this behavior was governed by the relatively weak incompatibility of the end blocks PS and PMMA in comparison to the strong incompatibility of PB block. Kabir et al [7] studied the morphological changes caused by the deformation and orientation of different domains, analyzing the influence of PB isomers (1,2 or 1,4). In the case of 1,2 isomercontaining SBM triblock copolymer, a co-existing lamellar and cylindrical morphology of PB block was observed, while for 1,4 isomer-containing one, only well segregated lamellar patterns were found.…”