Article
Chemistry, Physical
Prateek Dwivedi, Atishay Shrivastava, Dipin Pillai, Naveen Tiwari, Rahul Mangal
Summary: The motion of biological swimmers in bodily fluids can be modeled using active droplets driven by micellar solubilization in a viscoelastic polymeric solution. By varying the surfactant and polymer concentration, the viscoelastic nature of the medium can be adjusted. At moderate Deborah numbers, the moving droplet exhibits a steady deformed shape and at higher Deborah numbers, time-periodic deformation and oscillatory transition in swimming mode are observed. This study unveils the previously unexplored complexity in the motion of active droplets in viscoelastic fluids.
Article
Polymer Science
Seung Heum Jeong, Soowon Cho, Chunggi Baig
Summary: This study presents a detailed analysis of the scaling behavior of chain rotation dynamics in shear flow for melt and dilute linear polymer systems. The results show that dilute systems with hydrodynamic interaction (HI) and excluded volume (EV) effects exhibit two distinct scaling behaviors of chain rotation time between the intermediate and strong flow regimes. In contrast, free-draining dilute polymer systems display a simpler single-scaling behavior throughout the intermediate-to-strong flow regimes. The combined HI and EV effects weaken the structural change of polymer chains and enhance chain rotation dynamics by disturbing chain stretch and alignment to the flow direction. The presence of intermolecular interactions between chains in melt systems leads to two distinct scaling behaviors of chain rotation time as well. The overall scaling behavior of chain rotation is determined by the kinematically stable angular regions near the flow direction, while the kinematically unstable angular regions exhibit affine chain rotation dynamics. This study provides important insights into the understanding of chain rotation dynamics in shear flow.
Review
Polymer Science
George David Joseph Phillies
Summary: The author demonstrates that the Rouse model is invalid in polymer melts and dilute solution, and proposes an alternative model – the hydrodynamic scaling model – which extends the Kirkwood-Riseman model. This model assumes that polymer dynamics are dominated by solvent-mediated hydrodynamic interactions, with chain crossing constraints as secondary corrections. The article presents a comprehensive review of this model, including rationales and predictions based on the renormalization group approach.
Article
Polymer Science
Anna Gosteva, Alexander S. Gubarev, Olga Dommes, Olga Okatova, Georges M. Pavlov
Summary: This study considers the peculiarities of viscosity data treatment for two series of polymer systems exhibiting associative properties. The interest in amphiphilic macromolecular systems is explained, as they are considered as micellar-forming structures in aqueous solutions and can carry hydrophobic biologically active compounds. Convenient ways to extract the correct value of intrinsic viscosity eta from combined analysis of Kraemer and Huggins plots are discussed. The obtained data provide insights into hydrophobic interactions in polymer chains and the size of charged chains depending on the ionic strength of solutions.
Article
Engineering, Chemical
Ning Li, Yunhui Pang, Zhiqian Sun, Yongxiang Sun, Zhuang Qi, Wangqing Li, Yue Liu, Bin Li, Zhenbo Wang, Hongbo Zeng
Summary: Polymers have a significant impact on the electrostatic demulsification efficiency of water-in-oil (W/O) emulsions by altering the motion characteristics of water droplets. The addition of polymers increases the polarity of the droplets, promoting their deformation and breakup under an electric field. The migration of polarized polymers and ions ultimately leads to droplet breakup.
SEPARATION AND PURIFICATION TECHNOLOGY
(2023)
Article
Polymer Science
Emmanuel N. Skountzos, Katerina S. Karadima, Vlasis G. Mavrantzas
Summary: The study investigates the impact of adsorbed domains and nanoparticle bridging chains on the properties of attractive polymer nanocomposite melts through MD simulations. The presence of adsorbed polymer significantly affects the dynamic and conformational properties of the nanocomposite, especially under conditions favoring higher surface-to-volume ratios. Moreover, the bridging chains drive the formation of a nanoparticle network which becomes denser and stronger with increasing concentration of the polymer matrix in nanoparticles.
Article
Polymer Science
Diego D. Soetrisno, Carina D. V. Martinez Narvaez, Vivek Sharma, Jacinta C. Conrad
Summary: We investigate the flow properties of PAM solutions with different molecular weights and dispersities through the dripping-onto-substrate protocol. Our study confirms that the occurrence of the coil-stretch hysteresis, controlled by the drag coefficient ratio of stretched and coiled polymer chains, affects the scaling exponent of the extensional relaxation time with concentration. By varying the molecular weight distribution, we find that the scaling exponent increases when the ratio exceeds 4.5 due to the presence of coil-stretch hysteresis.
Article
Agriculture, Multidisciplinary
Monique Barreto Santos, Ianne Caroline Alves Isabel, Edwin Elard Garcia-Rojas
Summary: This study evaluated the effect of high-intensity ultrasound on depolymerization of aqueous TG solutions. The results showed that ultrasound effectively reduced the molecular weight and viscosity of TG, while increasing its solubility. Moreover, ultrasound did not alter the chemical structure of TG, only breaking down the polymer structure.
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
(2022)
Article
Mechanics
San Kim, Jun Hyeok Choi, Dong Kee Sohn, Han Seo Ko
Summary: To achieve uniform and high-resolution jetting, the physical properties of inks, such as supply pressure control, can be adjusted. Increasing negative supply pressure reduces the velocity and volume of the ink droplets. The printability diagram, which takes into account ink properties and operating conditions, was used to analyze the jetting behavior. It was concluded that controlling the supply pressure with slight reduction in droplet velocity and volume can enhance printing stability and frequency.
Article
Mechanics
S. A. Vagner, S. A. Patlazhan, C. A. Serra, D. Funfschilling, V. G. Kulichikhin
Summary: This study focuses on the mechanisms of dripping and jetting flow modes of viscoelastic semi-dilute polyacrylamide aqueous solutions co-flowing with silicone oil. A phase diagram of different flow modes is established, showing the control of filament elongation velocity in dripping mode and the evolution of thread diameter in jetting mode. The universal evolution of filament and bead sizes, independent of concentration and flow rates, is revealed.
Article
Medicine, Research & Experimental
Rajat Dandekar, Arezoo M. Ardekani
Summary: Concentrated monoclonal antibody solutions exhibit high viscosity due to fluid occlusion from trapped solvent molecules within the boundaries formed by aggregated antibodies. A theory based on antibody molecule geometry and aggregate morphology can be used to predict antibody viscosity. Controlling drug viscosity can be achieved at the molecular design stage using insights from the viscosity equation.
MOLECULAR PHARMACEUTICS
(2021)
Article
Biophysics
Xujie Wang, Congde Qiao, Kai Song, Song Jiang, Jinshui Yao
Summary: The study investigated the effect of different Hofmeister anions on the molecular conformation of gelatin in dilute solutions. The results showed that the intrinsic viscosity of gelatin decreased with kosmotropic anions and increased with chaotropic anions. The hydration entropy of kosmotropic anions was found to be correlated with the intrinsic viscosity of gelatin, indicating the strong hydration effect of kosmotropes. The molecular conformation of gelatin was modulated by Hofmeister anions through the hydration and interaction effects on the polymer chains.
COLLOIDS AND SURFACES B-BIOINTERFACES
(2021)
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
Mechanics
Bhanuday Sharma, Savitha Pareek, Rakesh Kumar
Summary: Extensive research has been conducted on the estimation of bulk viscosity in dense monatomic fluids, but little attention has been given to the same in dilute gas regime. This study used molecular dynamics simulations and the Green-Kubo method to precisely estimate the bulk viscosity of argon gas at atmospheric conditions. It was found that the bulk viscosity of dilute monatomic gases is several orders of magnitude smaller than that of other gases, but not absolute zero.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2023)
Article
Polymer Science
Jorgo Merchiers, Carina D. V. Martinez Narvaez, Cheryl Slykas, Naveen K. Reddy, Vivek Sharma
Summary: The study demonstrates that PEO solutions formulated with AcN and water as solvent mixtures can be centrifugally spun into fibers. Spinnability and fiber morphology are found to depend on factors such as solvent choice, polymer concentration, solution shear rheology, entanglements, and centrifugal spinning parameters. By contrasting shear relaxation time with evaporation rate, an intrinsic spinnability map for VE polymer solutions is obtained. A processability map for centrifugal spinning is plotted based on extensional relaxation time and time of flight, taking various influencing factors into account.
Article
Materials Science, Coatings & Films
Zahra Khalkhali, Kashyap Sundara Rajan, Jonathan P. Rothstein
JOURNAL OF THERMAL SPRAY TECHNOLOGY
(2020)
Article
Engineering, Mechanical
Anita A. Dey, Yahya Modarres-Sadeghi, Jonathan P. Rothstein
JOURNAL OF FLUIDS AND STRUCTURES
(2020)
Article
Physics, Fluids & Plasmas
Saeed Jafari Kang, Samrat Sur, Jonathan P. Rothstein, Hassan Masoud
PHYSICAL REVIEW FLUIDS
(2020)
Article
Physics, Multidisciplinary
Elaheh Alizadeh-Birjandi, Faryar Tavakoli-Dastjerdi, Judy St. Leger, Kym F. Faull, Stephen H. Davis, Jonathan P. Rothstein, H. Pirouz Kavehpour
EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS
(2020)
Article
Engineering, Mechanical
Samrat Sur, Nicholas Uvanovic, Hassan Masoud, Jonathan P. Rothstein
Summary: The study investigated the Marangoni propulsion of spheres and elliptical disks floating on the air-water interface to understand the influence of particle shape on their motion and stability at moderate Reynolds numbers. Self-propulsion of the particles was achieved by coating them with soap or isopropyl alcohol, creating a surface tension gradient that propelled them forward. It was observed that particle shape and surface tension gradient played a significant role in determining the motion characteristics of the particles.
JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME
(2021)
Article
Mechanics
Anita A. Dey, Yahya Modarres-Sadeghi, Jonathan P. Rothstein
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2020)
Article
Engineering, Multidisciplinary
Mitchel L. Timm, Saeed Jafari Kang, Jonathan P. Rothstein, Hassan Masoud
Summary: This paper presents a self-powered, remotely controlled surfing robot that utilizes surface tension modification for propulsion and steering, with a design focusing on novel release valve and steering mechanisms. The robot measures about 110 mm in length, reaching speeds up to 0.8 body length per second, while exhibiting a linear speed following a 1/3 power law with the release rate of the propellant. Additionally, the robot demonstrates the ability to withstand 20 mm s(-2) in centripetal acceleration during maneuvers.
BIOINSPIRATION & BIOMIMETICS
(2021)
Article
Mechanics
Pieter R. Boersma, Jay Zhao, Jonathan P. Rothstein, Yahya Modarres-Sadeghi
Summary: Recent studies have shown that vortex-induced vibration (VIV) can be observed at subcritical Reynolds numbers, contrary to previous beliefs. Experimental evidence confirms VIV at subcritical Reynolds numbers as low as certain values.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Nanoscience & Nanotechnology
Mengfei Huang, Yuan Liu, Zahra Khalkhali, Ara Kim, Weiguo Hu, Jae-Hwang Lee, Jonathan P. Rothstein, John Klier, Jessica D. Schiffman
Summary: Epoxy-encapsulated microparticles with core-shell structures synthesized via suspension polymerization enable high-efficiency, room-temperature cold spray processing. Microparticles with pure resin cores exhibit the lowest viscosity and highest deposition efficiency.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Biochemical Research Methods
Aditi R. Naik, Yiliang Zhou, Anita A. Dey, D. Leonardo Gonzalez Arellano, Uzodinma Okoroanyanwu, Ethan B. Secor, Mark C. Hersam, Jeffrey Morse, Jonathan P. Rothstein, Kenneth R. Carter, James J. Watkins
Summary: The research demonstrates a smart bandage microfluidic platform for cortisol detection and continuous glucose monitoring integrated with a synthetic skin. Through a series of tests, the potential of this low-cost, real-time sweat sensor for human health monitoring is validated.
Article
Multidisciplinary Sciences
Ali Alshehri, Jonathan P. Rothstein, H. Pirouz Kavehpour
Summary: Drop-wise condensation has been a focus of scientific research, with continuous drop-wise condensation showing potential for improving condensation rate and reducing the impact of non-condensable gases. Experimental results demonstrate that shedding droplet size can be effectively tuned by adjusting jet parameters.
SCIENTIFIC REPORTS
(2021)
Article
Engineering, Multidisciplinary
Samuel Bechard, Mitchel L. Timm, Hassan Masoud, Jonathan P. Rothstein
Summary: This paper investigates the improvement of a miniature remote-controlled robot that mimics insect locomotion. By controlling the release of isopropyl alcohol, the robot can propel and steer across the water. The study finds that the optimized single-footpad robot outperforms the two-footpad robot, with a 30% improvement in speed and a 400% improvement in maneuverability.
Article
Materials Science, Multidisciplinary
Sunilkumar Khandavalli, Nisha Sharma-Nene, Sadia Kabir, Samrat Sur, Jonathan P. Rothstein, Kenneth C. Neyerlin, Scott A. Mauger, Michael Ulsh
Summary: The concentration of PAA carrier polymer affects the microstructure and rheological properties of catalyst inks for polymer-electrolyte membrane fuel cells. Both ionomer and PAA stabilize catalyst particles against agglomeration. Increasing PAA concentration enhances particle stability and extensional viscosities of inks, promoting the formation of uniform nanofibers. However, excessive PAA concentration can lead to increased shear viscosities and defective fiber morphologies.
ACS APPLIED POLYMER MATERIALS
(2021)
Review
Mechanics
Jonathan P. Rothstein, Hadi Mohammadigoushki
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2020)
Article
Chemistry, Physical
Anita A. Dey, Yahya Modarres-Sadeghi, Anke Lindner, Jonathan P. Rothstein