Article
Chemistry, Physical
Ying Chen, Ran Yan, Nanrong Zhao
Summary: Macromolecular crowding is crucial for the dynamics in living cells. This study investigates the effects of polymer flexibility on the diffusion dynamics of passive and active particles in a solution of polymer chains. The results show that polymer stiffness inhibits the diffusion of passive particles but promotes the diffusion of active particles. Active particles can take advantage of the alignment of polymer chains, resulting in enhanced diffusivity.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Polymer Science
Farshad Safi Samghabadi, Ali H. Slim, Maxwell W. Smith, Maede Chabi, Jacinta C. Conrad
Summary: The structure and dynamics of polyelectrolytes have different effects on the transport of anisotropic particles compared to neutral polymers. This study investigates the transport of semiflexible M13 bacteriophage in aqueous solutions of sodium polystyrenesulfonate with varying ionic strengths. The results show non-Gaussian distributions of particle displacements and the presence of multiple diffusive modes.
Article
Biochemical Research Methods
Oskar E. Stroem, Jason P. Beech, Jonas O. Tegenfeldt
Summary: Regular patterns emerge in high-concentration DNA solutions in microfluidic pillars at low Reynolds numbers and high Deborah numbers. Interacting vortices between pillars lead to long-range traveling waves consisting of DNA. The position of the pillars in each unit cell plays a role in the formation of waves. Elastic effects are identified as central to the origin of these waves, and this research may contribute to improving sample processing in microfluidics and understanding viscoelastic mechanisms.
Article
Physics, Multidisciplinary
Michael C. Burroughs, Yuanyi Zhang, Abhishek M. Shetty, Christopher M. Bates, L. Gary Leal, Matthew E. Helgeson
Summary: This study experimentally confirmed the concentration profile of entangled polymer solutions under shear, demonstrating the critical importance of flow-concentration coupling in such systems. The findings showed that at shear rates above a critical value, concentration and velocity profiles can develop bands, consistent with model predictions.
PHYSICAL REVIEW LETTERS
(2021)
Article
Multidisciplinary Sciences
Mythreyi Unni, Shehaab Savliwala, Brittany D. Partain, Lorena Maldonado-Camargo, Qingteng Zhang, Suresh Narayanan, Eric M. Dufresne, Jan Ilavsky, Pawel Grybos, Anna Koziol, Piotr Maj, Robert Szczygiel, Kyle D. Allen, Carlos M. Rinaldi-Ramos
Summary: The diffusion behavior of polymer-coated inorganic nanoparticles in synovial fluid can be well described by the Stokes-Einstein relationship, with an effective medium viscosity much smaller than the macroscopic low shear viscosity of the fluid. The additional viscous dissipation in the effective medium viscosity is attributed to the presence of polymer segments, shedding light on the diffusive behavior of these nanoparticles in complex and crowded biological environments such as the joint.
Article
Mechanics
Tsutomu Indei, Tetsuharu Narita
Summary: This study investigates the single chain dynamics of entangled poly(ethylene oxide) in semidilute aqueous solutions using high-frequency micro-rheology and classical shear macro-rheology. The research finds that the dynamic moduli measured by the two methods show good agreement in the low-frequency range and reveals the presence of a Rouse regime in the high-frequency range.
JOURNAL OF RHEOLOGY
(2022)
Article
Thermodynamics
Fengyun Zhang, Xiaoda Wang, Qinglian Wang, Chen Yang, Ting Qiu
Summary: The addition of nanoparticles can enhance interfacial mass transfer, with hydrophilic nanoparticles promoting mass transfer and hydrophobic/amphiphilic nanoparticles inhibiting solute transfer. The smallest size nanoparticles at maximum concentration lead to the highest enhancement of mass transfer.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Polymer Science
Atsushi Matsumoto, Chi Zhang, Frank Scheffold, Amy Q. Shen
Summary: The entanglement dynamics and viscoelasticity of polyelectrolyte solutions were studied, showing discrepancies between experimental measurements and Dobrynin's model predictions, indicating the influence of electrostatic interactions on the viscoelastic properties of polyelectrolyte solutions.
Article
Polymer Science
Yanfei Tang, John E. McLaughlan, Gary S. Grest, Shengfeng Cheng
Summary: This study applies a method of simulating the drying process of a soft matter solution by moving the liquid-vapor interface. Interesting phenomena such as polymer-on-top stratification and core-shell nanoparticle clusters are observed. The results also validate the applicability of the method to various drying systems.
Article
Chemistry, Physical
Sergei A. Egorov
Summary: Mode-coupling theory is utilized to compute the nanoparticle diffusion coefficient in polymer solutions, showing agreement with molecular dynamics simulation data. The theory explains the effects of nanoparticle size, mass, and concentration on the diffusion coefficient and offers a microscopic interpretation of the nonmonotonic dependence of diffusion coefficient on nanoparticle concentration. Both size dependence and mass dependence indicate a significant breakdown of the Stokes-Einstein relation for the model.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Hamed Sharifi Dehsari, Morteza Hassanpour Amiri, Kamal Asadi
Summary: Experimental realization of thin films with significant room-temperature magnetoelectric coupling coefficient α(ME) without an external DC magnetic field has been challenging. Here, large α(ME) of 750 +/- 30 mV Oe(-1) cm(-1) is achieved in multiferroic polymer nanocomposites (MPCs) thin films. The MPCs consist of PMMA-grafted cobalt-ferrite nanoparticles uniformly dispersed in piezoelectric polymer P(VDF-TrFE). Nanoparticle agglomeration is reduced by surface functionalization with PMMA, enabling the uniform dispersion of nanoparticles in submicrometer thin films. This research can promote the development of flexible and printable multiferroic electronic devices for sensing and memory applications.
Article
Polymer Science
Dejie Kong, Sourya Banik, Michael J. San Francisco, Megan Lee, Rae M. Robertson Anderson, Charles M. Schroeder, Gregory B. McKenna
Summary: Bulk rheology measurements on concentrated monodisperse ring-linear DNA mixtures are reported for the first time. The behavior of these mixtures is compared with that of pure linear DNA, highlighting the dominant role of linear chains in the dynamics and entanglement scaling of the blends.
Article
Chemistry, Physical
Yusuke Koide, Susumu Goto
Summary: The study focused on the flow-induced scission of wormlike micelles in nonionic surfactant solutions under shear flow. A method to evaluate the longest relaxation time of unentangled surfactant micelles was proposed, showing its essential role in flow-induced scission. Conditional statistics based on the aggregation number of micelles revealed the conditions for flow-induced scission.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Mahmud Kamal Raihan, Sen Wu, Heston Dort, Micah Baghdady, Yongxin Song, Xiangchun Xuan
Summary: The effect of changing the depth of contraction-expansion microchannels on the flow responses of three types of polymer solutions and water was investigated. The flow of viscoelastic polyethylene oxide (PEO) solution became more stable in the contraction part while being less stable in the expansion part with the increase of the channel depth. In contrast, the entire flow became less stable in deeper channels for the shear-thinning xanthan gum (XG) solution as well as the shear thinning and viscoelastic polyacrylamide (PAA) solution.
Article
Chemistry, Physical
Bingyu Cui, Maxim Sukharev, Abraham Nitzan
Summary: This work investigates the quantum mechanical description of the interaction between photons and molecules. Approximation schemes, such as perturbation theory and mean-field Hartree approximation, are commonly used. The truncated 1-exciton model is found to be suitable for strong coupling approximation, and its results agree well with semiclassical mean-field calculations in several prototype problems.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Anthony J. J. Cooper, Michael P. P. Howard, Sanket Kadulkar, David Zhao, Kris T. T. Delaney, Venkat Ganesan, Thomas M. M. Truskett, Glenn H. H. Fredrickson
Summary: We have developed a multiscale simulation model for predicting solute diffusion through porous triblock copolymer membranes. The model combines self-consistent field theory (SCFT) and on-lattice kinetic Monte Carlo (kMC) simulations. Solvation is simulated in SCFT by constraining the glassy membrane matrix while relaxing the brush-like membrane pore coating against the solvent. The kMC simulations capture the resulting solute spatial distribution and concentration-dependent local diffusivity in the polymer-coated pores.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Ryan C. Roberts, Jeremy C. Palmer, Jacinta C. Conrad
Summary: We use molecular simulation to study the dynamics of supercooled liquids confined in quasi-2D slit geometries. The confined systems exhibit subdiffusive behavior on intermediate time scales and eventually crossover to diffusive behavior. The confinement also leads to long-wavelength fluctuations in the lateral direction parallel to the confining walls. The magnitude of the fluctuations increases with the lateral dimensions of the system and follows the logarithmic scaling predicted for 2D Mermin-Wagner fluctuations.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Chemistry, Physical
Shiv Rekhi, Dinesh Sundaravadivelu Devarajan, Michael P. Howard, Young C. Kim, Arash Nikoubashman, Jeetain Mittal
Summary: Interaction strength and localization are critical factors for controlling the properties of intrinsically disordered proteins (IDPs). Using models of IDPs, we found that different sequences and models showed similar characteristics at the single-chain level but exhibited surprising phase behavior. Models with distributed interactions favored the formation of liquid-like condensates over a wider range of sequences compared to models with localized interactions.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Chemistry, Multidisciplinary
Daniel P. Keane, Colby J. Constantine, Matthew D. Mellor, Ryan Poling-Skutvik
Summary: In this study, a telechelic, triblock copolymer (SEOS) is used to form elastic networks of polymer-linked droplets in emulsions. By controlling the fraction of chains that form bridges, the linear elasticity and yield stress of the emulsions can be tuned. The telechelic triblock copolymer also alters the yielding behavior and processability of the linked emulsions.
Article
Polymer Science
Manuel Troemer, Elias M. Zirdehi, Arash Nikoubashman, Andre H. Groeschel
Summary: The effect of block-selective surfactants on the confined assembly of a triblock terpolymer SBM was analyzed. It was found that different surfactants led to different morphologies and structures of the assembled microparticles. This study provides important insights into the microphase separation of block copolymers under confinement.
MACROMOLECULAR RAPID COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Jacinta C. Conrad, Megan L. Robertson
Summary: Breadth in the molecular weight distribution is an inherent feature of synthetic polymer systems. Recent studies have shown that altering the molecular weight distribution can change the properties of surface-grafted polymer brushes. This Perspective describes advances in synthetic methods to control the molecular weight distribution of surface-grafted polymers and highlights how shaping this distribution can generate novel or enhanced functionality in these materials.
Article
Chemistry, Physical
Yuki Kanakubo, Chiho Watanabe, Johtaro Yamamoto, Naoya Yanagisawa, Hiroki Sakuta, Arash Nikoubashman, Miho Yanagisawa
Summary: Living cells are characterized by the confinement of macromolecules at high concentrations. This study shows that this confinement-induced heterogeneity also occurs in single-component polymer solutions. The structural heterogeneity leads to slower transport of small molecules in cell-sized droplets compared to bulk solutions. Molecular simulations support the confinement-induced distribution by polymer length and the effect of conformational entropy.
Article
Chemistry, Physical
E. Nikoumanesh, R. Poling-Skutvik
Summary: In this study, the researchers created model thixotropic yield-stress fluids with tunable moduli and thixotropic kinetics by altering the ionic strength of a suspension of cellulose nanocrystals. They used a novel rheological protocol to identify the underlying physics of the yield transition and recovery of the cellulose gels. The researchers found that the thixotropic kinetics collapse onto a single master curve and fitted it to a transient solution to a diffusion-aggregation model.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
C. Levi Petix, Mohamamdreza Fakhraei, Chris A. Kieslich, Michael P. Howard
Summary: Surrogate modeling is used to separate the computation of relative entropy from the computation of its gradient, potentially improving the efficiency and stability of using relative entropy for inverse design.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Takahiro Yokoyama, Yusei Kobayashi, Noriyoshi Arai, Arash Nikoubashman
Summary: In this study, the self-assembly of amphiphilic nanocubes into finite-sized aggregates was investigated using molecular dynamics simulations and kinetic Monte Carlo calculations. The results showed that the nanocubes could form stable aggregates when the binding energy exceeded the thermal energy. Under shear, more frequent collisions between nanocube clusters led to faster aggregation dynamics but smaller terminal steady-state mean cluster sizes.
Article
Chemistry, Physical
Xin Yuan, Harold W. Hatch, Jacinta C. Conrad, Amanda B. Marciel, Jeremy C. Palmer
Summary: We investigated the pH response of sequence-controlled polyampholyte brushes (PABs) using molecular simulation. We found that the ionization state, height, lateral structure, and chain conformations of PABs differed from polyelectrolyte brushes. Grafting density had a modest effect on PAB properties, while monomer sequence strongly influenced the pH response, with the extent increasing with block size. This behavior is attributed to electrostatic attractions between oppositely charged blocks, leading to increased chain backfolding.
Article
Chemistry, Physical
Ryan C. Roberts, Jeremy C. Palmer, Jacinta C. Conrad
Summary: We used molecular simulation to study the dynamics of supercooled liquids confined in quasi-2D slit geometries. We found that similar to bulk supercooled liquids, the confined systems exhibit subdiffusive dynamics on intermediate time scales, followed by a crossover to diffusive behavior. Additionally, the confined liquids show long-wavelength fluctuations (LWFs) in the lateral directions parallel to the confining walls, similar to those observed in 2D but not 3D systems.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Polymer Science
Shahryar Ramezani Bajgiran, Farshad Safi Samghabadi, Si Li, Jacinta C. Conrad, Amanda B. Marciel
Summary: Through investigating the swelling behavior of weak polybasic brushes in different pH values and the fraction of ionizable monomers, the effects of charge on the swelling behavior and charge state of the brushes are elucidated. These findings are important for tailoring pH-responsive surfaces.
