Article
Polymer Science
Wengang Zhang, Fernando Vargas-Lara, Sara V. Orski, Kathryn L. Beers, Jack F. Douglas
Summary: This study utilized molecular dynamics simulations to investigate basic configurational properties of a coarse-grained model of linear low-density polyethylenes with short-chain branching in an implicit solvent, accounting for solvent quality effects. The model demonstrated a transition from repulsive inter-polymer interactions in a good solvent to collapse due to self-attractive intermolecular interactions in a very poor solvent regime, with a compensation point identified in between. A dimensionless measure of excluded volume interaction parameter delta was defined for comparison with experimental data under variable solvent conditions.
Article
Mechanics
Long-Zan Wang, Xianfu Huang, Quanzi Yuan, Longquan Chen, Ying-Song Yu
Summary: In this study, the behavior of impinging dilute sodium dodecyl sulfate (SDS) droplets on micropillar-arrayed polydimethylsiloxane surfaces was experimentally investigated, revealing the significant influence of surface roughness and SDS concentration on the droplet behaviors. The narrow range of dimensionless Weber number, We, plays a crucial role in the complete rebound of impacting SDS droplets, with theoretical analysis and experimental data comparison conducted on the lower and upper limits of impact velocity. Additionally, the addition of SDS can notably reduce the contact time of bouncing droplets, while the maximum spreading factor is more influenced by SDS concentration than surface roughness, following a scaling law of We(1/4).
Article
Chemistry, Multidisciplinary
Jingjie Jiang, Ehsan Nikbin, Garion Hicks, Shaofei Song, Yang Liu, Edmond C. N. Wong, Ian Manners, Jane Y. Howe, Mitchell A. Winnik
Summary: By heating and cooling, various PFS BCPs can form uniform spherulitelike structures in various solvents. The growth trajectory of these structures is from elongated lamellae into hedrites, sheaf-like micelles, and finally spherulites. General prerequisites for fabricating PFS BCP spherulites in solution have been identified, including corona/PFS core block ratios and the formation of secondary crystals on the basal faces of platelets in early stages of self-assembly. Manipulation of the self-assembly protocol can regulate the size and shape of the structures.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Glen McHale, Nan Gao, Gary G. Wells, Hernan Barrio-Zhang, Rodrigo Ledesma-Aguilar
Summary: This study investigates the friction characteristics of liquid on solid surfaces, defines friction coefficients for droplets and contact lines, and analogizes them with Amontons' laws. By utilizing surface free energy considerations, it is found that the frictional force is directly proportional to the surface tension force. These findings have important implications for the design of superhydrophobic surfaces and the control of droplet motion.
Article
Chemistry, Multidisciplinary
Abhinav Naga, Doris Vollmer, Hans Juergen Butt
Summary: This study demonstrates that particles rotating at a liquid-fluid interface need to overcome a resistive capillary torque due to contact angle hysteresis. The capillary torque reduces the mobility of wet granular matter and prevents small particles from rotating when in Brownian motion at an interface. The expression for the capillary torque is equivalent to the friction force that a drop experiences when moving on a flat surface.
Article
Chemistry, Multidisciplinary
Hong-Ji Yan, Zhen-Hua Wan, Feng-Hua Qin, De-Jun Sun
Summary: Polymer-substrate interactions and impact velocities play a crucial role in suppressing rebound behavior of dilute polymer solution droplets on a flat superhydrophobic substrate.
Article
Chemistry, Multidisciplinary
C. W. Extrand
Summary: This theoretical work estimates the volume and energies associated with the formation of a liquid meniscus along a vertical flat wall using existing equations. A proposed mechanism and energy balance is presented, along with derived equations for wetting work, surface energy, gravitational energy, and dissipation. The analysis indicates that the energy released during wetting is stored in various forms depending on variables such as surface tension, density, and wall wettability.
Article
Chemistry, Physical
Peyman Rostami, Mohammad Ali Hormozi, Olaf Soltwedel, Reza Azizmalayeri, Regine von Klitzing, Guenter K. Auernhammer
Summary: We investigated the wetting properties of PDMS pseudo-brush anchored on glass substrates, which exhibited lower contact angle hysteresis compared to hydrophobic silanized substrates. The effect of different molar masses of PDMS on the wetting properties was found to be negligible. The extremely smooth surface of the PDMS pseudo-brush explained the reduction in contact angle hysteresis and made it useful for wetting experiments. The dynamics of the four-phase contact point on PDMS pseudo-brushes were substantially different from other substrates, with changes depending only slightly on the molar mass of PDMS, leading to increased traveling speed and a different power law of position vs time.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Mahesh Kumar Singh, Himanshu Tiku, M. S. Bobji
Summary: The process of evaporation is complex and influenced by diffusion, convection, and heat transfer equations. The rate at which a liquid droplet evaporates from a solid substrate depends on the diffusion rate of vapor. Liquid evaporation is a natural phenomenon that occurs over time if the surrounding medium is not saturated. The size of the droplet is related to time, and the effect of droplet parameters on different substrates can change over time.
Article
Mechanics
Junting Xiang, Elnaz Hajizadeh, Ronald G. Larson, Damian Nelson
Summary: Analytical results of polymer migration in a two-dimensional rotational shearing flow between eccentric cylinders were obtained under certain conditions. The effects of eccentricity, perturbation variables, and confinement level on the polymer concentration pattern were investigated. Different migration behaviors, such as stress-gradient-induced and wall-depletion-induced migration, were observed in the study.
JOURNAL OF RHEOLOGY
(2021)
Article
Chemistry, Physical
Fang Wang, Ulf D. Schiller
Summary: This paper presents lattice Boltzmann simulations of liquid droplets on two parallel cylindrical fibers, investigating different final shapes resulting from spreading and retraction on the fibers. Three possible equilibrium configurations are observed, along with a region of bistability that spans both the column regime and the droplet regime. Additionally, a simulation protocol is presented to probe hysteresis of shape transitions. These insights into droplet shape transformations on fibers can be used to develop fiber-based materials and microfluidic systems.
Article
Chemistry, Physical
Shervin Issakhani, Omid Jadidi, Jafar Farhadi, Vahid Bazargan
Summary: Controllable accumulation of carbon nanotubes in smart patterning and printed electronics can be achieved by inclining the substrate and inhibiting droplet spreading by sharp solid edges. The results show that confining the droplet contact line to remain pinned to the pedestal edge significantly improves the width, uniformity, and precision of the deposited patterns. Combining confinement and inclination techniques yields promising deposited patterns with high consistency and low resistivity.
Article
Mechanics
Diego Diaz, Xiaomei Li, Pravash Bista, Xiaoteng Zhou, Fahimeh Darvish, Hans-Juergen Butt, Michael Kappl
Summary: We investigated the charge separation of bouncing drops on hydrophobic surfaces and found that it can be significantly higher than on superhydrophobic surfaces. The presence of self-generated electrostatic forces between the drop and the surface was observed, affecting the rebounding height and retraction motion of the drops. Our calculations showed that these electrostatic forces can be stronger than gravity, reducing the restitution coefficients up to 50%. This new approach provides an advantage compared to other methods for drop charge detection that require more complex setups.
Article
Mechanics
Xiaolong Zhang, Vadim S. Nikolayev
Summary: This paper presents a theoretical analysis of the liquid film dynamics during the oscillation of a meniscus in a cylindrical capillary, considering factors such as dynamic profile, finite film length, pinned contact line, and contact angle variations. The study also explores the average film thickness as a function of system parameters and compares numerical results with experimental data and quasi-steady approximation. Additionally, the paper discusses the effects of superheating on the oscillating meniscus process and the possibility of contact line recession due to evaporation.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Chemistry, Physical
Volfango Bertola
Summary: The micro-scale morphology of the receding contact line of dilute polyethylene oxide solution drops on a fluorinated hydrophobic surface is investigated. Transient liquid filaments and dendritic structures are observed, which evolve into a bead-on-a-string structure similar to the capillary breakup mechanism of dilute polymer solutions. The quantitative estimation of the average polymer force per unit contact line length explains the reduction of the contact line retraction velocity observed experimentally.
COLLOIDS AND INTERFACES
(2022)
Article
Medicine, Legal
Nathan D. Smith, James S. Sharp
Article
Medicine, Legal
Tshaiya Devi Thandauthapani, Adam J. Reeve, Adam S. Long, Ian J. Turner, James S. Sharp
Article
Multidisciplinary Sciences
Bin Yang, Nathan D. Smith, Andreas Johannes, Manfred Burghammer, Mike I. Smith
SCIENTIFIC REPORTS
(2018)
Article
Physics, Applied
James S. Sharp, Stuart F. Poole, Benjamin W. Kleiman
PHYSICAL REVIEW APPLIED
(2018)
Article
Multidisciplinary Sciences
Christopher G. Tompkins, James S. Sharp
SCIENTIFIC REPORTS
(2019)
Article
Chemistry, Physical
John F. Niven, Gurkaran Chowdhry, James S. Sharp, Kari Dalnoki-Veress
EUROPEAN PHYSICAL JOURNAL E
(2020)
Article
Biochemical Research Methods
Maria Giovanna Lizio, Zhiyu Liao, Dustin W. Shipp, Radu Boitor, Raluca Mihai, James S. Sharp, Matthew Russell, Hazem Khout, Emad A. Rakha, Ioan Notingher
Summary: The new technique combining auto-fluorescence spectral imaging and Raman spectroscopy allows for fast intraoperative assessment of excision margins in breast conserving surgery, providing information regarding tumor location within 45 minutes.
BIOMEDICAL OPTICS EXPRESS
(2021)
Article
Multidisciplinary Sciences
N. D. Smith, M. R. Swift, M. I. Smith
Summary: The dynamics of a bouncing ball on a rough vibrating surface were studied through experiments and simulations, revealing a strong enhancement of frictional interaction with the surface near walls. This enhanced dissipation, due to the coupling between collision, rotation, and surface friction, was found to be up to three times larger than inelastic collision, leading to increased probability density near boundaries and particle-particle spatial correlations. The findings suggest that particle collision properties cannot be considered independently of the surface's frictional properties.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Physical
M. J. Hayes, M. Smith
Summary: Adhesion tests were conducted on concentrated suspensions of Kaolin clay. Different slip behaviors were observed at low and high concentrations, which can be modified by adjusting surface roughness, initial compressive load, and separation velocity. The interaction between particles and surface topography appears to be concentration-dependent, resulting in varying slip characteristics.
EUROPEAN PHYSICAL JOURNAL E
(2021)
Article
Microbiology
Manuel Romero, Alessandro Carabelli, Michael R. Swift, Michael Smith
Summary: Decades after incorporating plastics into consumer markets, research shows that microplastic pollution has become a global problem. This study focuses on the interactions between microplastics and bacteria, using polystyrene microparticles as a model. The researchers found that Pseudomonas aeruginosa's production of Psl exopolysaccharide plays a crucial role in microplastic adhesion to bacterial cells, and the mobility of bacteria and external flow are important factors in the aggregation of microplastics.
ENVIRONMENTAL MICROBIOLOGY
(2022)
Article
Physics, Multidisciplinary
J. G. Downs, N. D. Smith, K. K. Mandadapu, J. P. Garrahan, M. Smith
Summary: Experimental investigation shows that the presence of interfacial tension between a granular liquid and crystal phase on a surface with periodically spaced dimples alters the order of the phase transition. The interplay of boundary inelasticity and geometry controls which phase, either granular crystal or granular fluid, makes contact with the edge. This induced wetting phenomenon has important consequences for the spatial separation of coexisting phases.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Physical
M. J. Hayes, M. Smith
Summary: This study explores the effect of aging on the break-up dynamics of Laponite suspensions in an extensional geometry. The results show that aging not only leads to stronger necking at the midpoint of the samples but also increases the stress overshoot with decreasing yield strain. However, the thinning curves in extension are found to be insensitive to the yield strain, suggesting significant plastic deformations in the samples before complete yielding. The implications of these findings for assessing the ductile-brittle nature of samples are also discussed.
EUROPEAN PHYSICAL JOURNAL E
(2022)
Article
Chemistry, Physical
James S. Sharp, Nathaniel M. Roberts
Summary: This study investigates the thickness dependence of telephone cord blister formation in solvent swollen PDMS thin films. By recording videos and using Python for analysis, the correlation between the width of telephone cord blisters, the wavelength of sinusoidal corrugations, blister growth rate, and film thickness is determined.
Article
Physics, Fluids & Plasmas
Joshua Eglinton, Mike Smith, Michael R. Swift
Summary: This paper describes simulations of active Brownian particles to investigate the influence of particle shape on dynamics and clustering. The study shows that composite particles can exhibit collective motion and modify the effective Peclet number. It also demonstrates how particle geometry can explain the phase behavior of multiple particles.
Article
Chemistry, Analytical
Charles J. Lee, David J. Scurr, Long Jiang, Andrew Kenton, Shaun R. T. Beebe, James S. Sharp
Summary: A rotation stage was developed to image the surface of bullet casings in ultra-high vacuum conditions using ToF-SIMS, and experiments were conducted to study the changes of fingermarks over time. By analyzing thin strips along the length of the casings and comparing the resulting images to those developed with cyanoacrylate and BY40, it was found that ToF-SIMS images displayed finer details of the fingermarks. The effects of curvature of the round casings on fingermark morphology were assessed, and distortions caused by differences in surface curvature and deposition methods were found to be acceptable.
