Thermal processing of diblock copolymer melts mimics metallurgy

Abstract

Small-angle x-ray scattering experiments conducted with compositionally asymmetric low molar mass poly(isoprene)--poly(lactide) diblock copolymers reveal an extraordinary thermal history dependence. The development of distinct periodic crystalline or aperiodic quasicrystalline states depends on how specimens are cooled from the disordered state to temperatures below the order-disorder transition temperature. Whereas direct cooling leads to the formation of documented morphologies, rapidly quenched samples that are then heated from low temperature form the hexagonal C14 and cubic C15 Laves phases commonly found in metal alloys. Self-consistent mean-field theory calculations show that these, and other associated Frank-Kasper phases, have nearly degenerate free energies, suggesting that processing history drives the material into long-lived metastable states defined by self-assembled particles with discrete populations of volumes and polyhedral shapes.

A Self‐Assembled Bicontinuous Cubic Phase with a Single‐Diamond Network

“…Figure 6. Models showing a) the micellar Fd " 3m cubic phase [27,28] and b) the new SD bicontinuous cubic phase of compounds 1/18-11/22.…”

Functional Macromolecular Systems: Kinetic Pathways to Obtain Tailored Structures

“…Thermodynamic processes alter the free‐energy landscape and may result in relaxation paths into novel (meta)stable structures. These aspects have just begun to be explored by simulation and experiments Development of SCFT techniques: One of the major advantages of SCFT and D‐DFT consists in their ability to readily obtain the free energy of configurations.…”

“…The thermodynamic process alters the free‐energy landscape and may result in relaxation paths into new (meta)stable structures. This exploration of process‐accessible structures has just begun to be explored by simulation and experiments …”

Rapid One‐Step Synthesis of Complex‐Architecture Block Polymers Using Inductively “Armed–Disarmed” Monomer Pairs

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