Article
Chemistry, Multidisciplinary
Jang Hwan Kim, Hyeon U. Jeong, Hye-In Yeom, Kyu Hyo Han, Geon Gug Yang, Hee Jae Choi, Jong Min Kim, Sang-Hee Ko Park, Hyeong Min Jin, Jaeup U. U. Kim, Sang Ouk Kim
Summary: Nanoscale block copolymer (BCP) self-assembly is used to finely align sub-10-nm-scale nanopatterns along the atomic edge of 2D flakes. The alignment mechanism is explained based on the wetting layer alternation of the BCP film in the presence of intermediate 2D flakes. The highly aligned nanocylinder templates with low roughness levels result in a sub-10-nm-wide graphene nanoribbon (GNR) array with significant switching characteristics.
ADVANCED MATERIALS
(2023)
Article
Polymer Science
Hyeongkeon Yoon, Seonghyeon Ahn, Qingshu Dong, Chungryong Choi, Eunyoung Kim, Weihua Li, Jin Kon Kim
Summary: This study investigated the formation of a multidomain double-stranded helical nanostructure, paving the way for the creation of multifunctional helical structures for various applications such as metamaterials. The experimentally observed morphology matched well with the prediction by self-consistent field theory.
Editorial Material
Nanoscience & Nanotechnology
Kevin G. Yager
Summary: The self-assembly of a triblock bottlebrush polymer at one length scale determines the organization of the self-assembly at a smaller scale, creating a hierarchical unit cell.
NATURE NANOTECHNOLOGY
(2023)
Article
Polymer Science
Thiago R. Guimaraes, Y. Loong Bong, Steven W. Thompson, Graeme Moad, Sebastien Perrier, Per B. Zetterlund
Summary: This study investigates the effect of the Z-group of RAFT agents on the nucleation step of aqueous RAFT PISA, revealing that the hydrophilicity of the Z-group influences the polymerization rates and chain extension success.
Article
Nanoscience & Nanotechnology
Dong Hyup Kim, Ahram Suh, Geonhyeong Park, Dong Ki Yoon, So Youn Kim
Summary: Nanoscratch-directed self-assembly (DSA) is introduced as a simple and scalable strategy to achieve highly aligned block copolymer (BCP) nanopatterns over a large area, allowing versatile nanofabrication for various functional nanomaterials.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Applied
Marieta Nichifor, Magdalena Cristina Stanciu, Florica Doroftei
Summary: The self-assembly potential of new amphiphilic block copolymers containing dextran and a semi-rigid deoxycholic acid-oligoethyleneglycol polyester was evaluated in terms of copolymer composition and self-assembly procedure. Different morphologies and sizes of aggregates were obtained by varying the polymer composition, with longer oligoethyleneglycol leading to smaller micelles and vesicles due to enhanced flexibility of the polyester hydrophobic block. Adjusting parameters allows for obtaining desired aggregate characteristics.
CARBOHYDRATE POLYMERS
(2021)
Article
Nanoscience & Nanotechnology
Jiajing Li, Paulina A. Rincon-Delgadillo, Hyo Seon Suh, Geert Mannaert, Paul F. Nealey
Summary: Directed self-assembly of block copolymers has attracted interest from the semiconductor industry due to its potential for achieving semiconductor-relevant structures with a relatively simple and low-cost process. However, the kinetic trapping of self-assembling structures into defective states poses challenges for high-volume manufacturing. A study on the kinetics of defect annihilation in chemoepitaxy DSA revealed a statistical model that suggests all dislocations can be removed by sufficiently long annealing time. Further analysis showed that the distribution of defects is largely influenced by the role of guiding stripes.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Physical
Ivan D. Rodichkin, Rustam A. Gumerov, Igor I. Potemkin
Summary: Amphiphilic miktoarm star copolymers with one long solvophobic arm and several short solvophilic arms were studied in a selective solvent. Different morphologies were obtained, and the diagram of states was found to be different from the diagram of linear diblock copolymers. The increase of the number of solvophilic arms led to the transition from vesicles to cylinders, and then to spherical micelles. The increase of solvent selectivity shifted the stability region of cylindrical micelles to more symmetric compositions.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Polymer Science
Tomohiro Miyata, Hsiao-Fang Wang, Takafumi Suenaga, Daisuke Watanabe, Hironori Marubayashi, Hiroshi Jinnai
Summary: Double-gyroid (DG) structured materials, with their unique three-dimensional network structures, show great promise for various applications. However, defects in these structures can significantly impact material properties. In this study, structural defects in a self-assembled DG structure of polystyrene-block-polyisoprene were observed using three-dimensional transmission electron microtomography. By characterizing the crystallography of the defects, it was found that multiple defect formation mechanisms coexist in self-assembled DG structures.
Article
Polymer Science
Stanislaw Sosnowski, Ryszard Szymanski, Francesca Lorandi, Mateusz Olszewski, Julian Sobieski, Rongguan Yin, Michael R. Bockstaller, Krzysztof Matyjaszewski
Summary: Numerical simulations showed that statistical copolymers with 1:1 BA/MMA composition have the highest contribution of alternating sequences, while batch ATRP of a 1:1 BA/MMA mixture generates gradient copolymers with diminished fraction of alternating sequences. A method for preparing statistical BA/MMA copolymers with the highest fraction of alternating sequences through normal ATRP copolymerization with MMA feeding was proposed to maximize the amount of alternating sequences in the copolymers.
Article
Polymer Science
Yao Sun, Fei Gao, Yuan Yao, Haibao Jin, Xinxin Li, Shaoliang Lin
Summary: A simple and robust strategy for light-induced reversible hierarchical self-assembly of block copolymers is presented, involving a two-step self-assembly process driven by solvent. The process is accompanied by reversible fluorescence, encapsulation, and controlled release, serving as a template for nanoparticle synthesis. This light-enabled reversible hierarchical self-assembly holds potential as a platform for smart delivery vehicles and nanomaterial templates.
Article
Nanoscience & Nanotechnology
Ling-Ying Shi, Sangho Lee, Qingyang Du, Bo Zhou, Lin Weng, Runze Liu, Caroline A. Ross
Summary: Thin films formed from silicon-containing conformationally asymmetric rod-coil diblock copolymers and triblock terpolymers under solvent annealing demonstrate the formation of various patterns such as zigzags, chevrons, Y-junctions, and line segments through directed self-assembly. The control of the orientation of cylindrical microdomains within trenches is achieved based on the chemical functionalization of the sidewalls and the shape of the trenches, determining the structure and location of concentric bends in the cylinders. The unique etching properties, spontaneous bends, and demonstrated periodicity and line/space ratios make these conformationally asymmetric rod-coil polymers appealing for nanoscale pattern generation.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Review
Polymer Science
Lin-Lin Xiao, Xu Zhou, Kan Yue, Zi-Hao Guo
Summary: Conjugated block copolymers (cBCPs) are promising materials with high conductivity and morphological versatility, making the study of their self-assembly behaviors crucial for enhancing device performance.
Article
Polymer Science
Rocco Di Girolamo, Chiara Santillo, Anna Malafronte, Miriam Scoti, Fabio De Stefano, Giovanni Talarico, Geoffrey W. Coates, Claudio De Rosa
Summary: Isotactic polypropylene-block-polyethylene block copolymers were synthesized and their crystallization behavior was studied. It was found that polyethylene blocks crystallize first, followed by the nucleation of polypropylene blocks. The polyethylene lamellar stacks have a higher periodicity of 30 nm, while the polypropylene lamellar stacks have a lower periodicity of 11-12 nm. The crystallization of the copolymer drives microphase separation and leads to a lamellar morphology.
Review
Chemistry, Physical
Weihua Li, Xueying Gu
Summary: Directed self-assembly (DSA) of block copolymers has been considered as one of the most promising bottom-up lithography techniques, successfully applied to fabricate large-scale ordered stripes and hexagonal arrays of dots. Recent studies have shown that a square array of cylinders can be stabilized in various AB-type block copolymers with specially designed architectures, indicating the potential development of an efficient DSA strategy for the fabrication of large-scale ordered square patterns in the future.
MOLECULAR SYSTEMS DESIGN & ENGINEERING
(2021)
Article
Chemistry, Multidisciplinary
Veronica Chappa, Yuliya Smirnova, Karlo Komorowski, Marcus Mueller, Tim Salditt
Summary: This study quantifies the effects of size polydispersity, thermal fluctuations, and membrane asymmetry on small unilamellar vesicles' (SUVs) curved bilayer using simulated Small Angle X-ray Scattering (SAXS) curves. The factorization approximation of the scattering intensity holds even for small vesicle radii, but curvature-induced asymmetry in the electron-density profile can arise for very small vesicles. Thermal fluctuations and size polydispersity have distinguishable signatures in the SAXS intensity, with polydispersity affecting low-q features and thermal fluctuations predominantly affecting scattering at larger q.
JOURNAL OF APPLIED CRYSTALLOGRAPHY
(2021)
Article
Chemistry, Physical
Marcus Mueller
Summary: Using analytical considerations and particle-based simulations, this study investigates the relaxation of a density modulation in a polymer system without nonbonded interactions. The results demonstrate that shallow density modulations, prepared by different processes but with identical amplitudes and wavevectors, exhibit different nonexponential decay behaviors, challenging the assumption that density alone characterizes the polymer system configuration. Analytic descriptions within Linear-Response Theory (LRT) and the Rouse model are provided, showing quantitative agreement with the particle-based simulations.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Polymer Science
Cody T. Bezik, Joshua A. Mysona, Ludwig Schneider, Abelardo Ramirez-Hernandez, Marcus Mueller, Juan J. de Pablo
Summary: A new mesophase in binary blends of A-b-(BA')3 miktoarm star block copolymers and A homopolymers has been discovered, consisting of aperiodic discrete domains of A embedded in a continuous matrix of B. Molecular bridging dominates the mechanical behavior of the mesophase, outweighing the influence of microphase segregation. The application of shear leads to a closer structure resembling its speculated discrete nature.
Article
Polymer Science
Gaoyuan Wang, Marcus Mueller
Summary: This study investigates the interplay between elasticity and microphase separation in quasi-two-dimensional phantom networks formed by AB diblock copolymers. Computer simulations and phenomenological considerations show that network elasticity has a minor role in the system when the stretching is weak. As the stretching increases, the incompatibility for the order-disorder transition decreases, and a multigrain state with tilted lamellae is observed at intermediate stretching.
Article
Materials Science, Multidisciplinary
Debashish Mukherji, Tiago Espinosa de Oliveira, Celine Ruscher, Jorg Rottler
Summary: This study investigates the phase behavior of poly(methyl methacrylate)-poly(lactic acid) blends and emphasizes the importance of considering the entropic contribution to the mixing Gibbs free energy change in controlling phase morphology. The study also shows how microscopic interaction details and molecular structures between different mixing species can affect mechanical and thermal properties.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Chemistry, Physical
David Steffen, Ludwig Schneider, Marcus Mueller, Joerg Rottler
Summary: This paper investigates the spatiotemporal autocorrelation of shear stress in a supercooled fluid close to the glass transition using molecular dynamics simulations. The results show anisotropic correlations and strongly damped oscillations at non-zero wavevectors. The experimental findings are in good quantitative agreement with a recently developed hydrodynamic theory.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Polymer Science
Gaoyuan Wang, Annette Zippelius, Marcus Mueller
Summary: Cross-linking is a versatile strategy to stabilize the structure and control the dynamics of polymers. This study systematically investigates the phase behavior of randomly cross-linked diblock copolymer melts and reveals the significant influence of the preparation state on the phase diagram.
Article
Polymer Science
Pritam Kumar Jana, Petra Bacova, Ludwig Schneider, Hideki Kobayashi, Kai-Uwe Hollborn, Patrycja Polinska, Craig Burkhart, Vagelis A. Harmandaris, Marcus Mueller
Summary: The theological properties of polymer composites depend on the interfacial interactions between solid fillers and a polymer fluid. This study presents a simulation strategy called the wall-spring thermostat, which uses transient bonds to mimic the interactions between the polymer and the solid surface. The density and lifetime of these transient bonds can be adjusted to control the single-chain and collective dynamics of the polymer at the surface. The simulation technique allows for the capture of dynamic heterogeneities at surfaces.
Editorial Material
Physics, Multidisciplinary
Daniel Bruns, Alireza Nojeh, A. Srikantha Phani, Jorg Rottler
PHYSICAL REVIEW LETTERS
(2022)
Article
Chemistry, Physical
Kai-Uwe Hollborn, Ludwig Schneider, Marcus Muller
Summary: Highly coarse-grained (hCG) linear polymer models, based on dissipative particle dynamics (DPD), allow for studying long time and length scales. This top-down strategy uses relevant interactions, such as molecular connectivity, and coarse-grained invariants, like the mean-squared end-to-end distance, to describe the equilibrium behavior of long, flexible macromolecules. However, describing the dynamics of long, entangled polymers is challenging because hCG models do not enforce the noncrossability of molecular backbones. One technique to mimic entanglements in hCG models is slip-springs, which has shown quantitative agreement with simulations, experiments, and theoretical predictions.
JOURNAL OF PHYSICAL CHEMISTRY B
(2022)
Article
Polymer Science
Oliver Dreyer, Gregor Ibbeken, Ludwig Schneider, Niklas Blagojevic, Maryam Radjabian, Volker Abetz, Marcus Mueller
Summary: In this study, the self-assembly of asymmetric diblock copolymers during solvent evaporation was investigated using particle-based Monte Carlo simulations and continuum modeling. The effects of evaporation rate and solvent selectivity on structure formation, particularly the alignment of minority block cylinders, were examined. Comparing the two simulation techniques helped identify general trends with parameter variation and understand the role of single-chain dynamics, fluctuations, and additional model details.
Article
Chemistry, Physical
Felix Weissenfeld, Lucia Wesenberg, Masaki Nakahata, Marcus Mueller, Motomu Tanaka
Summary: The interactions between vesicle and substrate were investigated using simulation and experiment. Polyacrylic acid brushes with cysteine side chains were grafted onto planar lipid membranes. The addition of Cd2+ ions compacted the polymer brushes and influenced the adhesion of lipid vesicles. Wetting of the vesicles occurred at [CdCl2] = 0.25 mM. The shape and adhesion of vesicles were quantitatively evaluated, and simulations revealed that wetting sensitivity was dependent on the interaction range.
Article
Physics, Fluids & Plasmas
Siavash Soltani, Chad W. Sinclair, Joerg Rottler
Summary: Using machine learning techniques, we have developed a Markov state model (MSM) to investigate the structural heterogeneities and slow dynamics of a model glass former. By coarse-graining the molecular dynamics into a low-dimensional feature space, we are able to reveal important aspects of the system's behavior. Our results show that the transition timescale between states is longer than the conventional structural relaxation time, but can still be obtained from shorter trajectories. The identified states in our model correspond to local excess Voronoi volume, highlighting packing fluctuations as a dominant factor in the slow relaxation of the system.
Article
Polymer Science
Niklas Blagojevic, Marcus Mueller
Summary: Using a particle-based model, a free-energy functional, and a lattice model, this study investigates the structure and motion of a grain boundary between two orthogonal grains in asymmetric block copolymers. The study reveals insights into transitions and correlations in space and time. By characterizing the system using a free-energy functional and calculating the minimum free-energy path, the study identifies a minimal set of transitions. The results are used to parametrize a lattice model and investigate grain-boundary motion by kinetic Monte Carlo simulation.
