Microphase-separation behavior of conjugated–amorphous block copolymers (BCPs) is driven by a complex interplay between Flory–Huggins interaction (χ), liquid crystalline (LC) interaction, and crystallization. Herein, in order to elucidate the influence of LC interaction on the morphology of the BCPs, we report the effects of regioregularity (RR) on the microphase separation and molecular packing structures of poly­(3-dodecyl­thiophene)-block-poly­(2-vinyl­pyridine) (P3DDT-b-P2VP). To decouple the effect of LC interactions from crystallization kinetics, we investigate the morphological behavior of the P3DDT-b-P2VP at above the melting temperature of P3DDT (∼160 °C). Both electron microscopy and X-ray scattering show an abrupt reduction in the domain spacing of both lamellar and cylindrical phases as the RR of P3DDT block increases. Specifically, lower RR (i.e., 85, 79, and 70%) BCPs have larger domain spacings than high RR (94%) by 50% (lamellar) or 80% (cylindrical), even though the overall molecular weights and P2VP volume fractions were similar for each RR. We propose that the RR-driven transition in domain spacing is caused by a change in P3DDT conformations and interchain interactions. When RR is low, the system assembles into a typical bilayer structure like other semiflexible and flexible block copolymer systems. When RR is high, the less flexible P3DDT chains are extended, driving their assembly into an LC monolayer. Significantly, this study demonstrates that tunable RR provides a simple route to manipulate melt state self-assembly of conjugated–amorphous materials.

Conjugated block copolymers (BCPs) can selfassemble into highly ordered nanostructures in a melt state. However, when cooled below the melting temperature, crystal growth can disrupt the self-assembled structure and produce a poorly ordered fibrillar texture. We demonstrate that crystallization modes of conjugated BCPs based on poly(3dodecylthiophene) (P3DDT) and poly(2-vinylpyridine) (P2VP) can be tuned through P3DDT regioregularity (RR), as this attribute controls the melting temperature and crystallization rates of P3DDT. When RR is low (70−80%), crystallization is observed at temperatures near or below the glass transition of P2VP, so crystal growth is largely confined by the glassy cylindrical or lamellar BCP structure. When RR is high (94%), crystallization occurs at 40 K above the glass transition of P2VP, so there is no longer a restriction of glassy domains. Importantly, crystal growth remains confined by the rubbery P2VP lamellae, but breaks through the rubbery P2VP cylinders. This morphology-dependent behavior is attributed to geometric compatibility of P3DDT crystal growth and the selfassembled symmetry. In a lamellar phase, the P3DDT chain orientations at the P3DDT-block-P2VP interface are compatible with crystal growth, and both the alkyl-stacking and π−π growth directions are unrestricted within a lamellar sheet. In a cylindrical phase, the radial orientation of P3DDT chains at the P3DDT-block-P2VP interface is not compatible with crystal growth, and the hexagonal close-packed symmetry only allows for one direction of unrestricted crystal growth. Significantly, these studies demonstrate that tuning RR of polyalkylthiophenes can open up multiple crystallization modes with the same monomer chemistries and block lengths, thereby decoupling the parameters that govern classical BCP self-assembly and crystal growth.

A series of diblock copolymers bearing a polymerized ionic liquid (polyIL) block (poly(N-(methacryloyloxy)ethyl-N,N-dimethyl-N-ethylammonium bis-(trifluoromethylsulfonyl)imide)) and a noncharged block (poly(methyl methacrylate) (PMMA)) or poly(n-butyl methacrylate) (PBuMA)) were studied using differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), wideangle X-ray scattering (WAXS), and broadband dielectric spectroscopy (BDS) to probe the effect of ion concentration on the morphology and ion transport in these polyelectrolytes. Two majority PMMA block copolymers, having mole ratios of the polyIL of 0.19 and 0.22, exhibited evidence of aggregation indicated by interfacial polarization in the dielectric spectra. The 0.19 mole ratio sample also displayed two distinct glass transitions by DSC. The SAXS measurements showed that no long-range order was present in these samples. The ionic conductivity of these samples were lower than the polyIL homopolymer due to hindered ion transport at the aggregate boundaries. Copolymers with majority polyIL blocks were found to exhibit disorder based on SAXS and DSC measurements. Furthermore, at a mole fraction of 0.91 of the polyIL the ionic conductivity was enhanced by a factor of ca. 1.5 with respect to the polyIL homopolymer, with a similar increase observed for the static dielectric permittivity. The effective number density and mobility of the ions were calculated for these systems from BDS and WAXS data, indicating that the enhancement of the ionic conductivity corresponds to an increase in the density of mobile charge carriers. The higher effective number density of charge carriers correlates with increased static dielectric permittivity, suggesting that ion pair dissociation is the likely mechanism behind the observed enhancement of ion transport. This study showcases the wealth of information that can be obtained from a combination of complementary experimental techniques.

Sulfonated block polymers are widely studied for applications in water management and electrochemical devices because they combine the properties of ionomers and thermoplastic elastomers in a single materials platform. Sulfonated block polymers are often processed into thin film membranes by casting from solution, and the resulting film morphology is strongly influenced by polymer−solvent interactions. In this work, we used mixtures of polar and nonpolar solvents to control solution-state interactions. We examined the self-assembled structures of solutions and corresponding films with small angle scattering and highresolution microscopies. When the solvent mixture is selective to one block, the polymer self-assembles into lamellar phases in solution, and films cast from these solutions are also lamellar. On the other hand, a more neutral solvent mixture will produce a disordered structure in solution, leading to films with a disordered, network-like arrangement of lamellar domains. These distinct film morphologies are confirmed with measurements of transport properties; the transition from ordered lamellae to a disordered network produces a 2-fold increase in water uptake and 5-fold increase in proton conductivity at 52% relative humidity. These studies demonstrate that measurements of solution-state structure can inform process development, providing a simple route to achieve targeted film morphologies and transport properties.

A thorough study of SSZ-39 formation, a next generation deNOx catalyst, is presented. The presence of the trans isomer is beneficial to the growth kinetics leading to enhancements in the growth rate, in some cases of over 40%. The formation of SSZ-39 is also sensitive to the composition of the faujasite used as an aluminum source as gels with identical compositions but different faujasites do not lead to SSZ-39 formation. Once SSZ-39 begins to form, its growth rate is linear and appears to equal the rate of faujasite dissolution. Finally, the Si/Al ratio of the material is influenced by the cis/trans ratio of the SDA. These results provide new insights into the formation of this industrially relevant catalyst.