Universalization of the Phase Diagram for a Model Rod−Coil Diblock Copolymer

Abstract

The Flory−Huggins interaction is measured for a model rod−coil block copolymer system, poly(alkoxyphenylenevinylene-b-isoprene), by fitting the interfacial segregation of block copolymer to a homopolymer interface and by using the random phase approximation (RPA) for block copolymers. The measured interfacial segregation of a block copolymer to the interface between homopolymers, fit with a self-consistent field theory (SCFT) simulation using χ as a variable parameter, gives a functional form χ = 34.8/T − 0.091. When RPA is applied to neutron scattering curves for the rod−coil system above the order−disorder transition, the theoretical structure factors are inconsistent with observed scattering curves due to complex aggregated structures formed in the nematic and isotropic states. Using the Flory−Huggins parameter and a previously measured value of the Maier−Saupe parameter, the PPV-b-PI phase diagram may be converted from system-specific variables to dimensionless parameters. Under the assumptions that the rods are ideal nematogens, interaction strengths are composition-independent, and rod−coil and rod−rod interactions are local, this yields the first quantitative universal phase diagram for rod−coil block copolymers.

Self-assembly of maltoheptaose-b-PMMA block copolymer systems: 10 nm Resolution in thin film and bulk states

“…Differently from flexible coil-coil BCPs, wherein phase diagram is parametrized primarily by the Flory-Huggins interaction and the volume fraction of the two blocks, rod-coil systems present additional complexities and their self-assembly behavior is fundamentally diverse from those of coil-coil BCPs. Given that the phase behavior of rod chains is also governed by a MaierSaupe parameter which characterizes the liquid crystalline interactions between the rod-like polymers, rod-coil materials cannot be simply considered by a model of Gaussian chain (Olsen & Segalman, 2005;Olsen & Segalman, 2006;Tao, Zohar, Olsen, & Segalman, 2007;Olsen, Shah, Ganesan, & Segalman, 2008).…”

Effect of polymer chemistry on globular protein–polymer block copolymer self-assembly

“…The observation that the lamellar phase is thermodynamically favored when the polymer volume fraction is much higher than 0.5 is consistent with previous observations of asymmetrically shaped block copolymers. [63][64][65][66]…”

Impact of intrinsic backbone chain stiffness on the morphologies of bottle-brush diblock copolymers

“…Despite significant theoretical advances, the modeling of the selfassembly behavior of di-and multi-block copolymers containing semiflexible units remains an outstanding challenge. [23,26,34,42] In the case of BB diblock copolymers with large aspect ratio, which is equivalent to using thick linear chains, [3] particular effort has been put in the formation of lamellar morphology. [10,12] However, low aspect ratio BB copolymers may not easily be described by a map on a linear chain architecture, because the "Flory theorem" does not generally extend to polymers having a non-trivial topology.…”