Article
Mechanics
Joy Mandal, Sandip Sarkar, Swarnendu Sen
Summary: This study investigates the path selection of bubbles suspended in different power-law carrier liquids in microfluidic channel networks, validated by numerical modeling and literature data. The results show that bubbles generally prefer channels with higher flow rates, but may also choose longer routes in certain circumstances.
Article
Chemistry, Multidisciplinary
Peiliu Li, Fei Zhan, Lei Wang
Summary: This study investigates the motion of droplets on anisotropic surfaces through experiments, theoretical models, and energy balance analysis. The research finds that the direction of droplet rebound on an anisotropic surface can be switched by designing the initial impacting velocity, and the motion of the droplet changes with an increase in impacting height.
Article
Thermodynamics
Yu Zhang, Zhentao Zhang, Junling Yang, Yunkai Yue, Huafu Zhang
Summary: A superhydrophobic surface with excellent evaporation characteristics and anti-adhesion properties was fabricated by a simple chemical etching method. Compared to smooth surfaces, the superhydrophobic surface reduced the evaporation rate of lower concentration droplets and delayed the evaporation of higher concentration droplets. Additionally, the superhydrophobic surface effectively reduced the adhesion of high viscosity liquids.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Nanoscience & Nanotechnology
Weishan Yan, Chaopeng Zhao, Wenyao Luo, Wangyang Zhang, Xi Li, Duo Liu
Summary: Controlled droplet manipulation using photothermally induced pyroelectric effects on a super-hydrophobic surface allows for versatile functionalities, including droplet deformation, jetting, splitting, and guided motion by adjusting the laser incident angle. The method offers potential applications in remote droplet control, with capabilities for contactless, electrodeless, and precise spatial and fast temporal control. The distribution of pyroelectric charges plays a crucial role in the process, with evenly distributed charges promoting hydrophobic to hydrophilic transitions and localized charges enabling droplet shape control.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Review
Chemistry, Multidisciplinary
Zhifeng Hu, Fuqiang Chu, He Shan, Xiaomin Wu, Zhichao Dong, Ruzhu Wang
Summary: This review comprehensively summarizes the progress on phenomena, mechanisms, regulations, and applications of droplet impact on superhydrophobic surfaces. The focal points are droplet contact and rebound, and various applications are classified according to their requirements. The review also points out the remaining challenges and outlines future research directions.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Analytical
Qiang Tang, Zongtang Zhang, Jia-Han Zhang, Feiran Tang, Chengjun Wang, Xiaxia Cui
Summary: In this study, rapid oscillatory motion of droplets in oil and on superhydrophobic surface was achieved by injecting charges. The injection of charges increased the flexibility of droplet motion. These findings have important implications for the design of microfluidics and micromechanical equipment.
Article
Mechanics
Yan Pang, Qingshan Yang, Xiang Wang, Zhaomiao Liu
Summary: This study investigates droplet generation in T-junction microchannels with contractive structures under different flow rates and viscosity conditions through numerical simulation. The research reveals that the droplet size decreases and then increases with increasing viscosity ratio, establishing a model for the transition of generation modes.
Article
Thermodynamics
Wen Li, Jingxin Wang, Linlin Tian, Chuling Zhu, Ning Zhao
Summary: The rebound dynamics of a microscale supercooled water droplet on a cold superhydrophobic surface were numerically studied. Four different regimes were observed during the impacting-freezing process, and the results were affected by the cold surface temperature, impact velocity, droplet diameter, and supercooled degree.
APPLIED THERMAL ENGINEERING
(2024)
Article
Nanoscience & Nanotechnology
Yiliang Li, Jinmei Huang, Jiang Cheng, Shouping Xu, Pihui Pi, Xiufang Wen
Summary: The wedge-shaped Ag/Cu surface with a wettability gradient was able to enhance droplet motion and remove the droplets away from the surface effectively. The theoretical evaluation of the driving force from the wettability gradient length was conducted to understand its impact on the movement.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Mechanics
Changhun Park, Jeong-Hyun Kim
Summary: This study investigates the bouncing dynamics of glycerol/water droplets impacting a grooved hydrophobic surface by changing the viscosity and impact speed of the droplets. It found that as the viscosity of the droplets increased, the Weber number range in which petal bouncing occurred decreased.
Article
Chemistry, Physical
Xiaotong Chen, Peng Wang, Dun Zhang, Junfei Ou
Summary: This study investigates the coalescence-induced droplet jumping behavior (CIDJB) of superhydrophobic surfaces on zinc substrate, and explores the effects of complex structure characteristics on CIDJB and subsequent atmospheric corrosion protection performance. The presence of nanostructures is found to be an important factor for successful CIDJB, and superhydrophobic surfaces with CIDJB exhibit better anti-corrosion performance compared to those without CIDJB.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2022)
Article
Nanoscience & Nanotechnology
Mirvahid Mohammadpour Chehrghani, Taher Abbasiasl, Abdolali Khalili Sadaghiani, Ali Kosar
Summary: Research shows that superhydrophobic surfaces can significantly enhance condensation heat transfer performance, as observed through visualization studies in mini-channels. Through observing droplet dynamics and changes in droplet size distribution in the condensation cycle, it is found that superhydrophobic surfaces contribute to improved heat transfer efficiency.
ACS APPLIED NANO MATERIALS
(2021)
Article
Multidisciplinary Sciences
Kai Hou, Dongshi Guan, Hangyu Li, Yongqi Sun, Yue Long, Kai Song
Summary: New programmable swimming actuators can execute wavelength-dependent multidirectional motions via the Marangoni effect, achieving various different motion modes. Additionally, a mechanical measurement system has been established for quantitatively measuring the driving force.
Article
Mechanics
Meng Shi, Ratul Das, Sankara Arunachalam, Himanshu Mishra
Summary: By surface engineering and fine-tuning liquid-solid adhesion, it is possible to achieve superhydrophobicity without lowering the Leidenfrost point. Water on superhydrophobic surfaces comprising doubly reentrant pillars (DRPs) can exceed that on hydrophilic and even superhydrophilic surfaces in terms of the Leidenfrost point.
Article
Chemistry, Multidisciplinary
Matti J. Hokkanen, Matilda Backholm, Maja Vuckovac, Quan Zhou, Robin H. A. Ras
Summary: Superhydrophobic coatings with unique properties such as self-cleaning and staying dry have recently emerged in industrial and consumer markets. The stochastic nature of coating components can affect the uniformity of water repellency, and traditional contact angle goniometry may not provide accurate quantification of wetting properties. The study demonstrates that highly sensitive force-based methods can offer advantages in quantifying microscale heterogeneity in superhydrophobic coatings.
ADVANCED MATERIALS
(2021)
Review
Chemistry, Multidisciplinary
Liwei Chen, Shilin Huang, Robin H. A. Ras, Xuelin Tian
Summary: Liquid-repellent surfaces, such as solid surfaces with flexible polymer brushes or alkyl monolayers, have unique liquid-like properties and can repel various liquids. They offer an alternative to superhydrophobic or superoleophobic surfaces and lubricated slippery surfaces. The liquid-like nature of these surfaces also has important implications for interface properties and applications. This review provides an overview of liquid-repellent surfaces, their mechanisms, and the challenges and opportunities they present.
NATURE REVIEWS CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
William S. Y. Wong, Mariia S. Kiseleva, Shaochen Zhou, Muhammad Junaid, Leena Pitkanen, Robin H. A. Ras
Summary: This study investigates the scalable room-temperature synthesis of stochastic nanoparticle surfaces with fluoro-free moieties. It demonstrates that both hydrocarbon- and dimethyl-silicone-based functionalization can achieve super-liquid-repellency without the need for perfluoroalkyls. Key guidelines are provided for achieving functional yet sustainably designed super-liquid-repellency.
ADVANCED MATERIALS
(2023)
Article
Physics, Multidisciplinary
Davide Riccobelli, Hedar H. Al-Terke, Paivi Laaksonen, Pierangelo Metrangolo, Arja Paananen, Robin H. A. Ras, Pasquale Ciarletta, Dominic Vella
Summary: We report surprising morphological changes of suspension droplets during evaporation, which are influenced by the presence of the hydrophobin protein HFBI. The formation of an elastic film occurs when the concentration of the solute reaches a critical value, resulting in different morphologies for pendant and sessile droplets. A gravito-elastocapillary model explains these differences and predicts droplet morphology and shape changes, highlighting the importance of gravity even for small droplets. These findings have implications for engineering and biomedical applications involving droplet shape control.
PHYSICAL REVIEW LETTERS
(2023)
Article
Multidisciplinary Sciences
Christopher Jonkergouw, Ngong Kodiah Beyeh, Ekaterina Osmekhina, Katarzyna Leskinen, S. Maryamdokht Taimoory, Dmitrii Fedorov, Eduardo Anaya-Plaza, Mauri A. Kostiainen, John F. Trant, Robin H. A. Ras, Paivi Saavalainen, Markus B. Linder
Summary: A water-soluble synthetic macrocycle, Pillar[5]arene, has been identified to bind to key virulence factors in Gram-negative pathogens, suppressing toxins and biofilms and enhancing the efficacy of standard antibiotics. It evades existing antibiotic resistance mechanisms and shows promise as a dual-acting anti-virulence treatment against Top Priority pathogens.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Sourov Chandra, Alice Sciortino, Susobhan Das, Faisal Ahmed, Arijit Jana, Jayoti Roy, Diao Li, Ville Liljestrom, Hua Jiang, Leena-Sisko Johansson, Xi Chen, Marco Nonappa, Marco Cannas, Thalappil Pradeep, Bo Peng, Robin H. A. Ras, Zhipei Sun, Olli Ikkala, Fabrizio Messina
Summary: A study reports on an atomically precise ultrasmall Au(I)(6) nanocluster with unique properties, including efficient third harmonic generation, intense photoluminescence, ultrafast quantum coherence, and electron accepting properties. The nanoclusters were formed through a sequential reduction protocol using ascorbic acid, and showed strong third harmonic generation response and excellent stability. The results suggest potential applications in multifunctional devices, fast photoswitches, and quantum colloidal devices.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Shaochen Zhou, Lotta Gustavsson, Gregory Beaune, Sourov Chandra, Jukka Niskanen, Janne Ruokolainen, Jaakko V. I. Timonen, Olli Ikkala, Bo Peng, Robin H. A. Ras
Summary: This work presents a general and efficient method to synthesize pH-responsive near-infrared (NIR) emitting gold nanoclusters by introducing aliphatic tertiary amine (TA) groups as ligands. The pH-responsive NIR emission is achieved through the protonation and deprotonation of TA groups, which induce electronic structure changes. The pH-responsive gold nanoclusters can serve as specific and sensitive probes for lysosomes in cells, offering non-invasive emissions without interference from intracellular autofluorescence.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Automation & Control Systems
Zoran M. Cenev, Ville Havu, Jaakko V. I. Timonen, Quan Zhou
Summary: Theoretical models are crucial for designing algorithms for feedback control of robotic micromanipulation platforms. They provide an understanding of the limits of each manipulation approach and identify key parameters that influence motion performance.
IEEE-ASME TRANSACTIONS ON MECHATRONICS
(2023)
Article
Chemistry, Multidisciplinary
Sakari Lepikko, Ygor Morais Jaques, Muhammad Junaid, Matilda Backholm, Jouko Lahtinen, Jaakko Julin, Ville Jokinen, Timo Sajavaara, Maria Sammalkorpi, Adam S. Foster, Robin H. A. Ras
Summary: This study challenges the traditional assumption of surface heterogeneity as the major factor that affects the motion of liquid droplets on solid surfaces. It reveals a counterintuitive mechanism of slipperiness that is not expected based on the chemical heterogeneity of the surface. This finding opens up new avenues for enhancing the mobility of droplets.
Correction
Multidisciplinary Sciences
Han Tao, Carlo Rigoni, Hailong Li, Antti Koistinen, Jaakko V. I. Timonen, Jiancheng Zhou, Eero Kontturi, Orlando J. Rojas, Guang Chu
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Han Tao, Carlo Rigoni, Hailong Li, Antti Koistinen, Jaakko V. I. Timonen, Jiancheng Zhou, Eero Kontturi, Orlando J. Rojas, Guang Chu
Summary: In this study, a series of heterogeneous colloidal suspensions are developed to exhibit both liquid-liquid phase separation of semiflexible binary polymers and liquid crystal phase separation of rigid, rod-like nanocellulose particles. The phase behavior of the multicomponent mixture is controlled by the trade-off between thermodynamics and kinetics during the two transition processes, showing cholesteric self-assembly of nanocellulose within or across the compartmented aqueous phases. The multicomponent mixture undergoes hierarchical self-assembly of nanocellulose and polymers into stratified cholesteric films upon drying, exhibiting compartmentalized polymer distribution and anisotropic microporous structure.
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Ricardo Reyes Garza, Nikos Kyriakopoulos, Zoran M. Cenev, Carlo Rigoni, Jaakko V. I. Timonen
Summary: Magnetic Quincke rollers offer versatile control mechanisms for studying single-particle dynamics and collective states, allowing the application of externally controllable forces and torques at high precision.
Review
Physics, Multidisciplinary
Dan Daniel, Maja Vuckovac, Matilda Backholm, Mika Latikka, Rahul Karyappa, Xue Qi Koh, Jaakko V. I. Timonen, Nikodem Tomczak, Robin H. A. Ras
Summary: Surface wetting, the interaction between a solid surface and a liquid droplet, plays a crucial role in nanoscience and industrial applications. This review explores how new surface characterization techniques have improved our understanding of surface wettability compared to traditional methods. The authors discuss various techniques, such as cantilever-based force probes and atomic force microscopy, that allow for a more detailed analysis of surface wetting properties. These advances in surface characterization techniques will contribute to the development of functional surfaces and materials for antifogging and antifouling applications.
COMMUNICATIONS PHYSICS
(2023)
Article
Chemistry, Physical
Arthur Vieira, Wenjuan Cui, Ville Jokinen, Robin H. A. Ras, Quan Zhou
Summary: Many natural and artificial water-repellent surfaces have micro- and nano-roughness and their wetting properties can be determined by observing the contact angles at the liquid-solid interface. However, a generally applicable method to directly observe the moving contact lines on such surfaces is missing. In this study, we demonstrate that a transparent droplet probe combined with a conventional optical microscope can accurately quantify the contact angles and contact area on water-repellent surfaces.
Correction
Chemistry, Multidisciplinary
Liwei Chen, Shilin Huang, Robin H. A. Ras, Xuelin Tian
NATURE REVIEWS CHEMISTRY
(2023)
