Article
Physics, Applied
E. Ruiz-Gutierrez, P. J. Baker, A. M. J. Edwards, M. Newton, I. C. Sage, R. Ledesma-Aguilar, G. McHale, C. Brown
Summary: This study demonstrates the formation of thin, rectangular shaped films of electrically insulating liquid on curved and flexible liquid repellent substrates using dielectrophoresis forces. The experimental threshold voltage for film formation is found to have a monotonic dependence on the substrate curvature. By considering the balance of stresses acting on the films, the researchers develop an analytical theoretical expression that is in excellent quantitative agreement with the experimental measurements. The results and the demonstrated programmable wettability on curved and flexible substrates provide foundations for various applications such as imaging, displays, and biochemical analysis.
APPLIED PHYSICS LETTERS
(2022)
Article
Mechanics
M. Rank, A. Voigt
Summary: This study investigates the influence of varying Gaussian curvature on anomalous vortex-network active turbulence on general surfaces using a numerical approach for a covariant generalized Navier-Stokes equation. The simulation results indicate an alignment of vortex chains with minimal curvature lines of the surface and a dependency of this turbulence regime on the sign and gradient of local Gaussian curvature.
Article
Chemistry, Analytical
Zhantao Wang, Xiaojuan Liu, Li Wang, Cunlu Zhao, Danfeng Zhou, Jiazheng Wei
Summary: This study reports for the first time the phenomenon of droplet trampolining using electrowetting and provides consistent results through experiments and simulations. The findings are important for applications that require vertical transportation of droplets or detachment of droplets from solid surfaces.
Article
Engineering, Electrical & Electronic
Xiaodong He, Bo Yang, Jing Li, Xiaoping Zhang, Youquan Deng
Summary: This study investigates the dynamic behaviors of droplet electrowetting on slippery lubricant-infused porous surfaces (SLIPS). Experimental and numerical analysis reveal that the droplet always spreads smoothly to the equilibrium state without overshooting on SLIPS. The increase of applied voltage leads to overdamping of the droplet, with the settling time proportional to the 0.9th power of the electrowetting number. Additionally, it is found that the droplet spreads slowly due to the dominance of viscous dissipation of the oil-water interface with increasing silicone oil viscosity. The friction coefficient is found to be nearly proportional to the 1/6th power of oil viscosity, while being minimally influenced by applied voltage and oil thickness.
SENSORS AND ACTUATORS A-PHYSICAL
(2022)
Article
Physics, Multidisciplinary
Yinan Dong, Roya Zandi, Alex Travesset
Summary: This letter addresses the problem of characterizing the structure of an elastic network constrained to a frozen curved surface. It proposes a new approach based on nonlinear elasticity without using any approximation. The results show agreement with linear elasticity beyond its strict range of applicability. The implications for virus assembly are also discussed.
PHYSICAL REVIEW LETTERS
(2022)
Article
Chemistry, Physical
Xiaodong He, Jing Li, Yongxiang Guan, Zhiyang Wang
Summary: In this study, the effects of substrate characteristics and lubricant thickness on the cloaking state, wetting state, and diffusion diameter of nanodroplets were investigated through molecular dynamics simulation. The results showed that the presence of a thicker lubricant layer on silicon nanopillar substrates increased the coating film of nanodroplets, while nanodroplets on copper nanopillar substrates remained in a non-cloaking state, even with a thicker lubricant layer. Additionally, the electrowetting behaviors of nanodroplets under external electric fields were examined, and the results demonstrated a transition from Cassie state to partial Wenzel state on both substrates. Moreover, the impact of lubricant layer thickness on nanodroplet electrowetting was analyzed, revealing that the reduction of apparent contact angle increased with lubricant layer thickness under a parallel electric field, and had a maximum value for a moderate lubricant thickness under a perpendicular upward or downward electric field.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Thermodynamics
Robin Pham, Run Yan, Sheng Wang, Chung-Lung Chen
Summary: In contrast to traditional point of view, electrowetting allows for dynamic wetting regime, where hydrophilicity can penetrate or recede based on liquid location rather than substrate structure. Droplets form clusters through size regulation as condensation accumulates and are transferred by coalescence cascades and mass imbalances. This passive electrostatic liquid conveyor enables the removal of condensation from self-stagnating cycles. Each working zone functions independently for nucleation and diffusion, accumulation and collection. 40 to 50 percent of the liquid recovery increase is attributed to spatial-size regulation, while higher nucleations are influenced by electrostatic voltage. The migration of condensates is determined by the competition between dropwise and filmwise tendencies. The autonomy of nucleations allows for unhindered electrostatic voltage, limited only by material strength and endurance. © 2023 Elsevier Ltd. All rights reserved.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Chemistry, Physical
Kaiwen Li, Zhanpo Han, Lidan Wang, Jiaqing Wang, Chuanwei Zhang, Jiahao Lin, Shiyu Luo, Li Peng, Wenzhang Fang, Yingjun Liu, Ziliang Wu, Yeqiang Tang, Chao Gao, Zhen Xu
Summary: Assembling two-dimensional sheets into three-dimensional forms allows for the creation of materials with rich functionalities. In this study, the wrinkling behaviors of graphene oxide sheets on curved surfaces were investigated, revealing a selection rule for wrinkling modes based on the curvature mismatch between the sheets and target surfaces. This research provides a general and quantitative description framework for wrinkling modulation of 2D materials and has implications for precise fabrication of particles and functional coatings.
Article
Chemistry, Physical
Kaiwen Li, Zhanpo Han, Lidan Wang, Jiaqing Wang, Chuanwei Zhang, Jiahao Lin, Shiyu Luo, Li Peng, Wenzhang Fang, Yingjun Liu, Ziliang Wu, Yeqiang Tang, Chao Gao, Zhen Xu
Summary: Assembling two-dimensional sheets into three-dimensional structures is a promising material design method. This research investigates the wrinkling behaviors of graphene oxide sheets assembled onto curved surfaces, revealing the selection rule of wrinkling modes and providing a quantitative description method that can guide the precise fabrication of particles and functional coatings.
Article
Engineering, Mechanical
Pearson A. Wyder-Hodge, Egor Larionov, Dinesh K. Pai
Summary: The article proposes a method to estimate the orientation of a measured surface during friction measurements using a custom-made hand-held tribometer. The method takes into account the position and orientation of the tribometer relative to the shape of the surface, and allows for lightweight tribometers to be built with cheaper materials without sacrificing accuracy.
TRIBOLOGY INTERNATIONAL
(2022)
Article
Engineering, Chemical
Ajit Kumar, Manabendra Pathak
Summary: In this study, the impact of droplets on hydrophobic and superhydrophobic surfaces was investigated using electrowetting technique. The results showed that the dynamics of the droplet were strongly influenced by the voltage amplitude, frequency, and surface hydrophobicity. Increasing the voltage amplitude enhanced the spreading of the droplet but reduced its recoiling rate, leading to partial or complete suppression of droplet rebound. The combination of voltage amplitude, frequency, and surface hydrophobicity affected the degree of droplet rebound suppression.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Physics, Applied
Chenwei Wei, Mengjia Cen, Hsiang-Chen Chui, Tun Cao
Summary: This study introduces a device based on TO technique that can control the propagation direction of surface waves by manipulating the refractive index, providing a new approach to manipulate surface wave propagation.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Xin He, Ben-Xi Zhang, Shuo-Lin Wang, Yi-Feng Wang, Yan-Ru Yang, Xiao-Dong Wang, Duu-Jong Lee
Summary: The study reveals that under an external electric field, a nanodroplet on pillar-arrayed surfaces can transition from an initial Cassie state to a partial wetting state, and eventually to a Wenzel state. The free-energy landscape shows multiple local energy minima, corresponding to multiple metastable states. It is found that the wetting transition from Wenzel to Cassie state is spontaneous only when the Cassie droplet is in a global energy minimum configuration.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Physics, Multidisciplinary
Samuel Bell, Shao-Zhen Lin, Jean-Francois Rupprecht, Jacques Prost
Summary: Cell monolayers are important model systems in the study of tissue biophysics, and the role of curvature in monolayer motion is not well understood. This study presents a hydrodynamic theory for the motion of an apical-basal asymmetric active nematic gel on a curved surface, demonstrating that curvature can qualitatively change the flow pattern of the monolayer.
PHYSICAL REVIEW LETTERS
(2022)
Article
Mathematics
Antonia Jabbour, Stephane Sabourau
Summary: We prove that every local supremum of the systole over the space of Riemannian metrics of curvature at most -1 on a given nonsimply connected closed surface is attained by a hyperbolic metric. As an application, we also present a partial extension of this result to 3-manifolds.
MATHEMATISCHE ANNALEN
(2023)
Article
Chemistry, Physical
Yiping Yin, Zhe Wang, Hua Zou
Summary: This study presents a novel method for preparing dimpled polymer-silica nanocomposite particles using interfacial swelling-based seeded polymerization. The optimized conditions allow for a relatively high percentage of dimpled particles to be achieved.
Article
Chemistry, Physical
Brenden D. Hoehn, Elizabeth A. Kellstedt, Marc A. Hillmyer
Summary: Porous materials with nanometer-scale pores have important applications as nanoporous membranes. In this study, ABA triblock copolymers were used as precursors to produce nanoporous polymeric membranes (NPMs) in thin film form by degrading the end blocks. Polycyclooctene (PCOE) NPMs with tunable pore sizes were successfully prepared using solvent casting technique. Oxygen plasma etching was employed to improve the surface porosity and hydrophilicity of the membranes. This study provides a straightforward method to produce tough NPMs with high porosity and hydrophilic surface properties.
Article
Chemistry, Physical
Vladislav S. Petrovskii, Stepan I. Zholudev, Igor I. Potemkin
Summary: This article investigates the behavior of linear and ring polypeptide chains in aqueous solution and explores the properties of the complexes formed by these chains with oppositely charged surfactants. The results demonstrate that the complexes of linear supercharged unfolded polypeptides and the corresponding surfactants exhibit impressive adhesive properties.
Article
Chemistry, Physical
Merve Cevik, Serkan Dikici
Summary: Cardiovascular diseases are a leading cause of death globally, and vascular grafts are a promising treatment option. This study focuses on tissue-engineered vascular grafts (TEVGs) using decellularized parsley stems as a potential biomaterial. The decellularized parsley stems showed suitable properties for TEVGs, providing a suitable environment for human endothelial cells to form a pseudo endothelium. This study showcases the potential of using parsley stems for TEVGs.
Article
Chemistry, Physical
Gustavo A. Vasquez-Montoya, Tadej Emersic, Noe Atzin, Antonio Tavera-Vazquez, Ali Mozaffari, Rui Zhang, Orlando Guzman, Alexey Snezhko, Paul F. Nealey, Juan J. de Pablo
Summary: The optical properties of liquid crystals are typically controlled by electric fields. In this study, we investigate the effects of microfluidic flows and acoustic fields on the molecular orientation and optical response of nematic liquid crystals. We identify several previously unknown structures and explain them through calculations and simulations. These findings hold promise for the development of new systems combining sound, flow, and confinement.
Article
Chemistry, Physical
Xinjun Wu, Xin Guan, Shushu Chen, Jiangpeng Jia, Chongyi Chen, Jiawei Zhang, Chuanzhuang Zhao
Summary: This research presents a novel shape memory hydrogel with a remodelable permanent shape and programmable cold-induced shape recovery behavior. The hydrogel is prepared using specific treatment methods to achieve shape fixation by heating and shape recovery by cooling. Additionally, deformable devices can be obtained by assembling hydrogel blocks with different concentrations.
Article
Chemistry, Physical
Rebecca Hengsbach, Gerhard Fink, Ulrich Simon
Summary: This study examines the properties of DNA functionalized pNipmam microgels and pure pNipmam microgels at different concentrations of sodium chloride and in PBS solutions using temperature dependent H-1-NMR measurements. The results show that DNA modification affects the volume phase transition temperature and the addition of salt and PBS further enhances this effect.
Article
Chemistry, Physical
Ningyi Li, Junhong Li, Lijingting Qing, Shicheng Ma, Yao Li, Baohui Li
Summary: This paper investigates the self-assembly behavior of colloids with competing interactions under spherical confinement and finds that different ordered structures can be formed under different sized spherical confinements. Moreover, more perforated structures are formed in smaller spheres.