Article
Chemistry, Physical
JingCun Fan, Joel De Coninck, HengAn Wu, FengChao Wang
Summary: This study investigates the capillary force balance at the contact line on rough solid surfaces and in two-liquid systems. It confirms the significant influence of solid-liquid interactions on the lateral component of capillary force and proposes a quantitative relation between surface roughness and transfer strategy. Moreover, the theoretical model includes capillary forces from both liquids in a two-liquid system, and the findings are supported by molecular dynamics simulations.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Engineering, Mechanical
Romain Lhermerout
Summary: The study performed Y Surface Force Balance (SFB) experiments in a dry atmosphere and across an ionic liquid, revealing that mechanical deformations of surfaces have significant impacts on force measurements. It was found that the contact radius on the ionic liquid can be described by the DMT model, contrary to the conventional belief that SFB experiments are always in the JKR regime. Additionally, the study observed that mica can experience compression in addition to bending, and proposed a modified procedure for calibrating mica thickness in a dry atmosphere. The structural forces measured across the ionic liquid were not described by the usual exponentially decaying harmonic oscillation, suggesting a convolution of surface forces and mechanical response of the solids.
Article
Chemistry, Physical
Bo Hou, Chunya Wu, Xiguang Li, Junjie Huang, Mingjun Chen
Summary: This study analyzed the forces and critical conditions on static sessile droplets deposited on hydrophobic micropillar-structured surfaces, proposing a new force-balance model which showed better agreement with experimental results compared to classical models. Integration of depinning mechanisms into the model allows for reliable estimations of critical conditions for the C-W transition during evaporation, providing appropriate geometric parameters for achieving high hydrophobic stability.
APPLIED SURFACE SCIENCE
(2021)
Article
Construction & Building Technology
Tuna Ulger, Ahmad Shayan Sharifi
Summary: This study investigated the bond-slip behavior between GFRP and concrete through experimental research and numerical simulations, and explored different parameters. The findings showed that the interface strength can improve the flexural capacity of the concrete-filled GFRP beams, and square GFRP box sections can be used instead of rectangular sections for constructing hybrid beams. Additionally, the increased compressive strength of concrete in hybrid beams can increase the load capacity and elastic stiffness of the hollow GFRP beams.
Article
Chemistry, Multidisciplinary
Resham Rana, Nicholas Hopper, Francois Sidoroff, Wilfred T. Tysoe
Summary: The rates of mechanochemical reactions increase exponentially with applied stress, but a critical stress is required to initiate a mechanochemical reaction. Density functional theory calculations and experimental measurements confirm this concept, providing insights into mechanochemical reaction mechanisms on surfaces and suggesting new approaches to designing robust surface films.
Article
Chemistry, Physical
Pablo F. Ibanez-Ibanez, Francisco J. Montes Ruiz-Cabello, Miguel A. Cabrerizo-Vilchez, Miguel A. Rodriguez-Valverde
Summary: The study demonstrates that the characterization of contact angle hysteresis on soft surfaces is sensitive to the measurement protocol and may have adventitious time-dependencies. The slow spontaneous relaxation of water drops on elastic surfaces may affect the observed values of contact angle hysteresis. The wetting properties of elastic surfaces should be properly examined with reliable values of contact angle measured after drop relaxation.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Engineering, Chemical
Yasuhiro Shimada, Motohiro Tsubota, Shuji Matsusaka
Summary: A centrifugal method was used to analyze particle-surface interactions, and a rigid-body model was employed to determine adhesion force and contact radius based on particle diameter, angular velocities, and surface roughness.
Article
Chemistry, Multidisciplinary
Lifei He, Shuwen Xi, Lei Ding, Beixing Li, Wei Mu, Peiqiang Li, Feng Liu
Summary: This study proposes an effective strategy for controlling pesticide efficiency, focusing on the impact dynamics of droplets and the determination of pinning points on the leaf surface. The combination of impact dynamics analysis and force balance model provides a constructive method to improve pesticide utilization on hydrophobic plant surfaces.
Article
Chemistry, Physical
Yongshuai Wen, Yongshou Liu, Zhe Yuan
Summary: The contact angle of nanodroplets on chemically patterned surfaces can be predicted more accurately by considering the varying contact line width. Molecular dynamics simulations are used to determine the contact line width and an empirical formula is derived to determine it. This allows for improved prediction of contact angles on chemically patterned surfaces.
SURFACES AND INTERFACES
(2023)
Article
Engineering, Electrical & Electronic
Kazuaki Fujita, Kenichi Fujii, Yasuyuki Yamamoto, Yuichi Ota, Naoki Kuramoto
Summary: A voltage balance using electrostatic force for accurate measurement of small masses and forces has been developed at the National Metrology Institute of Japan, enabling traceable mass measurements based on the revised definition of the kilogram. The reliability of the apparatus was confirmed by determining the mass of a 2 mg wire weight and performing uncertainty analyses, with results in agreement with NMIJ's mass standard.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2021)
Article
Materials Science, Characterization & Testing
Yanbin Zhang, Zehua Xu, Kangshuai Li, Xiaosen Wang, Qiang He
Summary: This study establishes a contact angle model for rectangular convex structures with anisotropy, and solves the droplet volume using the integral method and cyclic assignment method. The characteristic dimensions of FKM surfaces prepared by template method are collected using visual recognition technology. The gravity, surface tension, and microdroplet height of droplets in the antenna model are verified. The results show that the empirical correction coefficient of the contact angle model is 0.04-0.112 when the droplet gravity and surface tension are equal. Additionally, the reliability of theoretical gravity and theoretical surface tension of droplets instead of actual values reaches 96.3% and 99.4% respectively. The droplets on six FKM surfaces all conform to the Wenzel-Cassie transition state model. Optimizing the theory of contact line density is beneficial for designing accurate and anisotropic rough structures.
Article
Engineering, Chemical
Shuwen Wang, Jiahui Chen, Zhiguo Liu, Michael Morgan, Xiaoxiao Liu
Summary: The measurement accuracy of vibratory surface finishing forces is affected by the wiring of the force sensor. A triaxial wireless force sensor is developed to solve this problem and measure the forces between media and workpiece surfaces in vibratory surface finishing. Experimental results show that normal impacts between the media and workpiece are dominant, and the mean forces on the front surface of the workpiece are larger than on the side and rear surfaces. The mass and shape of media significantly affect the forces, which in turn affect the surface roughness and hardness of the workpiece.
Article
Engineering, Multidisciplinary
Hossein Jafarzadeh, Gholam Hossein Farrahi, Valery I. Levitas, Mahdi Javanbakht
Summary: Phase field theory for fracture is developed at large strains with a correct introduction of surface stresses at nanoscale. The expression for surface stresses is consistent with the sharp surface approach and is a result of geometric nonlinearities. The study provides important connections between material parameters and presents a complete system of equations in both deformed and undeformed configurations.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2022)
Article
Engineering, Mechanical
Jintao Wang, Shengguan Qu, Fuqiang Lai, Xiongfeng Hu, Yunqing Deng, Xiaoqiang Li
Summary: The combined strengthening method significantly increased the surface hardness and reduced the surface roughness of 20CrMoH steel, leading to a longer rolling contact fatigue life.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Engineering, Marine
Ying Li, Yuezhen Wang, Zhifeng Liu, Xiaodong Yang, Caixia Zhang, Yanhong Cheng
Summary: The clamping force relaxation caused by contact creep at ambient temperature has a significant impact on the service performance of offshore structures. Maxwell and Kelvin architectures are used to analyze the creep displacement of rough surfaces in contact, and a theoretical model is established to describe the functional relationship between contact creep and clamping force relaxation. Experimental results validate the proposed model, and it is found that clamping force relaxation is proportional to surface roughness. Therefore, controlling surface topography and bolt preload can effectively improve the performance of bolted joints for steel structures.
Article
Polymer Science
Juan J. de Pablo, Heyi Liang, Michael A. Webb, Manasi Chawathe, Denis Bendejacq
Summary: Understanding and predicting the behavior of galactomannans in aqueous solutions is important for various applications. In this study, a coarse-grained model of guar gum, a type of galactomannan, was developed and validated. The model showed good agreement with experimental results in terms of chain structure, aggregate formation, and solution viscosity. The behavior of guar gum in water was explained using scaling theory for polymers in good solvents.
Article
Polymer Science
Michael Jacobs, Yuan Tian, Andrey V. Dobrynin
Summary: We investigated the equilibrium swelling of brush gels experiencing large uniaxial deformations in contact with solvent. Our study revealed that the swelling ratio of the brush gels, Qeq(A), which describes the change in volume upon swelling, is a nonmonotonic function of the gel uniaxial deformation ratio A. The behavior of Qeq(A) is a result of the optimization of polymer/solvent interactions and conformational entropy of brush strands in the nonlinear deformation regime. The location of the maximum in the Qeq(A) function is directly related to the value of the strain-stiffening parameter fi.
Article
Polymer Science
Anish Gulati, Michael Jacobs, Carlos G. Lopez, Andrey V. Dobrynin
Summary: We studied the viscosity of semidilute aqueous solutions of sodium polystyrenesulfonate as a function of polymer and salt concentrations. The viscosity data were quantified by applying a scaling relationship between solution correlation length and number of monomers for chains with monomer projection length. The specific values of the B-parameter were determined by various factors such as the fraction of charged monomers, the effective solvent quality, the chain Kuhn length, and the monomer-solvent interactions. The values of the B-parameters were obtained from the plateaus of normalized specific viscosity as a function of monomer concentration.
Article
Chemistry, Physical
Wei Liu, Cheng Zhang, Riccardo Alessandri, Benjamin T. Diroll, Yang Li, Heyi Liang, Xiaochun Fan, Kai Wang, Himchan Cho, Youdi Liu, Yahao Dai, Qi Su, Nan Li, Songsong Li, Shinya Wai, Qiang Li, Shiyang Shao, Lixiang Wang, Jie Xu, Xiaohong Zhang, Dmitri V. Talapin, Juan J. de Pablo, Sihong Wang
Summary: We have synthesized stretchable electroluminescent polymers that can achieve near-unity theoretical quantum yield through thermally activated delayed fluorescence. Our polymers display 125% stretchability and 10% external quantum efficiency, and demonstrate a fully stretchable organic light-emitting diode. Stretchable light-emitting materials are crucial for the development of skin-like displays and optical biostimulation applications.
Correction
Chemistry, Physical
Wei Liu, Cheng Zhang, Riccardo Alessandri, Benjamin T. Diroll, Yang Li, Heyi Liang, Xiaochun Fan, Kai Wang, Himchan Cho, Youdi Liu, Yahao Dai, Qi Su, Nan Li, Songsong Li, Shinya Wai, Qiang Li, Shiyang Shao, Lixiang Wang, Jie Xu, Xiaohong Zhang, Dmitri V. Talapin, Juan J. de Pablo, Sihong Wang
Article
Green & Sustainable Science & Technology
Longyan Wang, Jian Xu, Zilu Wang, Bowen Zhang, Zhaohui Luo, Jianping Yuan, Andy C. C. Tan
Summary: This paper presents a novel static fluid-structure interaction (FSI) tool based on deep learning to cost-efficiently analyze the fluid-structure coupling of a hydrofoil. By adopting a convolutional neural network (CNN) to predict the fluid force and finite element method (FEM) to solve the solid structure response, a new CNN-FEM framework with an iterative scheme for solving the FSI problem is developed. The results show that this method yields extremely close prediction results and is 100 times more computationally efficient than the commercially developed software (Ansys Workbench).
Article
Polymer Science
Andrey V. Dobrynin, Ryan Sayko, Ralph H. Colby
Summary: Viscosity analysis is a valuable technique for polymer characterization. This study proposes a new method to determine the molecular weight of polymers by representing the solution-specific viscosity as a generalized universal function of chain overlap concentration.
Article
Nanoscience & Nanotechnology
Mitchell R. Maw, Alexander K. Tanas, Erfan Dashtimoghadam, Evgeniia A. Nikitina, Dimitri A. Ivanov, Andrey V. Dobrynin, Mohammad Vatankhah-Varnosfaderani, Sergei S. Sheiko
Summary: Hot-melt pressure-sensitive adhesives (HMPSAs) are widely used in various applications and often contain large quantities of plasticizers and tackifiers to enhance adhesive performance. This study introduces an alternative additive-free approach to HMPSA design using self-assembled bottlebrush graft-copolymers, which maintain the moldability of traditional thermoplastic elastomers while providing benefits such as extreme softness for substrate wetting, low melt viscosity for molding and 3D-printing, and a wide range of viscoelastic responses. The graft-copolymers have five independently controlled architectural parameters that regulate the adhesive properties.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Polymer Science
Zilu Wang, Yuan Tian, Andrey V. Dobrynin
Summary: This research focuses on the swelling and deformation of polyelectrolyte gels. It is found that the swelling ratio of polyelectrolyte gels first increases and then decreases with increasing deformation ratio. The location of the maximum swelling ratio shifts towards larger deformations with increasing salt concentration and decreasing fraction of charged groups.
Article
Chemistry, Physical
Andrey V. Dobrynin, Yuan Tian, Michael Jacobs, Evgeniia A. Nikitina, Dimitri A. Ivanov, Mitchell Maw, Foad Vashahi, Sergei S. Sheiko
Summary: Our lives rely heavily on polymer networks, from synthetic rubber to biological tissues. However, the internal structure of these networks has remained a mystery since the discovery of rubber vulcanization in 1839. In this study, the authors developed a forensic approach to decode the network structure by analyzing its nonlinear mechanics, allowing for quality control in network synthesis and classification based on stress distribution effectiveness. This is a crucial step towards implementing artificial intelligence principles for soft matter design.
Article
Multidisciplinary Sciences
Yan N. Fang, Artem M. Rumyantsev, Angelika E. Neitzel, Heyi Liang, William T. Heller, Paul F. Nealey, Matthew V. Tirrell, Juan J. de Pablo
Summary: Polyelectrolyte complexation plays a crucial role in materials science and biology. Small-angle scattering experiments have revealed structural similarities between polyelectrolyte complexes (PECs) and semidilute solutions of neutral polymers. The positional correlations between polyanion and polycation charges have been investigated using small-angle neutron scattering profiles, and the results indicate the existence of Coulomb repulsions between polyanion fragments and their attractions to polycations. The addition of salt leads to the disappearance of these correlations, reverting the scattering functions to an Ornstein-Zernike form.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Nanoscience & Nanotechnology
Mitchell R. Maw, Alexander K. Tanas, Erfan Dashtimoghadam, Evgeniia A. Nikitina, Dimitri A. Ivanov, Andrey V. Dobrynin, Mohammad Vatankhah-Varnosfaderani, Sergei S. Sheiko
Summary: Hot-melt pressure-sensitive adhesives (HMPSAs) are widely used materials in various applications. The traditional formulation of HMPSAs involves the use of thermoplastic elastomers with added plasticizers and tackifiers. However, this study presents an alternative additive-free approach using bottlebrush graft-copolymers that exhibit self-assembly properties and can regulate the adhesive performance through five architectural parameters.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Mitchell Maw, Erfan Dashtimoghadam, Andrew N. Keith, Benjamin J. Morgan, Alexander K. Tanas, Evgeniia Nikitina, Dimitri A. Ivanov, Mohammad Vatankhah-Varnosfaderani, Andrey V. Dobrynin, Sergei S. Sheiko
Summary: In this study, a precise additive-free platform for pressure sensitive adhesive (PSA) design was developed. By utilizing the unique properties of brush-like elastomers, a wide range of adhesion force was achieved with a single polymer chemistry. This approach will be essential for the future implementation of AI technology in molecular engineering of PSAs.
ACS CENTRAL SCIENCE
(2023)
Article
Multidisciplinary Sciences
Samantha M. Mcdonald, Quansan Yang, Yen-Hao Hsu, Shantanu P. Nikam, Ziying Hu, Zilu Wang, Darya Asheghali, Tiffany Yen, Andrey V. Dobrynin, John A. Rogers, Matthew L. Becker
Summary: The authors report succinate-based copolyesters with barrier properties that can extend the functional lifetime of resorbable bioelectronic devices.
NATURE COMMUNICATIONS
(2023)
