Article
Chemistry, Multidisciplinary
Haoguan Gui, Jieyi Chen, Tiantian Yang, Shixiang Zuo, Xiazhang Li, Chao Yao, Fuxin Liang
Summary: A series of Janus hemispheres with a patchy hemispherical surface and a flat undersurface were synthesized through controlled polymerization-induced phase separation. The hemispherical shape was achieved by polymerizing styrene within wax droplets, followed by grafting hydrophilic polymers on the exposed surface. The patchy hemispherical surface was obtained by introducing hydrophobic acrylate monomers and controlling the polymerization-induced phase separation. The Janus hemispheres were used to fabricate coatings with tunable wettability by grafting zwitterionic polymers.
Article
Chemistry, Multidisciplinary
Wei Wang, Bing Han, Yang Zhang, Qi Li, Yong-Lai Zhang, Dong-Dong Han, Hong-Bo Sun
Summary: This paper presents the use of laser-induced graphene (LIG) tape as stick-on photothermal labels for developing light-driven actuators based on the Marangoni effect. Graphene patterns with superior photothermal properties are prepared on polyimide (PI) tape using direct laser writing technology, enabling the creation of photothermal Marangoni actuators that can be folded into 3D origami actuators allowing both translation and rotation. The graphene-based photothermal Marangoni actuators demonstrate biocompatibility and can be manipulated by various light sources, showing promise for developing light-driven soft robots.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Zesheng Hua, Guangxu Liu, Jia Man, Jianyong Li, Chenchen Zhou, He Xia, Jianfeng Li
Summary: This study focuses on the phase separation phenomena and spreading behavior of suspended droplets at the air-liquid interface. By utilizing solvent evaporation-induced droplet phase separation, suspended Janus droplets with different morphologies and patchy structure were created. A modified spreading coefficient theory was constructed to predict the phase separation at the air-droplet interface, and factors leading to droplets being able to float were studied. This research has significant potential in various applications for material synthesis.
Article
Chemistry, Physical
R. T. van Gaalen, H. M. A. Wijshoff, J. G. M. Kuerten, C. Diddens
Summary: The study investigates the relationship between thermal Marangoni flow and surfactant dynamics using two numerical models. It is found that insoluble surfactants can suppress the thermal Marangoni flow if their concentration is sufficiently large and evaporation and diffusion are slow. Soluble surfactants, on the other hand, can either reduce or increase interfacial velocity depending on their sorption kinetics. The study also shows that a small concentration of insoluble surfactants can significantly decrease the tangential flow velocity at the interface. The numerical models are validated through comparison in cases where both are applicable.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Kai Feng, Jose Carlos Urena Marcos, Aritra K. Mukhopadhyay, Ran Niu, Qiang Zhao, Jinping Qu, Benno Liebchen
Summary: This study reports the first all-aqueous droplet swimmer powered by self-generated polyelectrolyte gradients, which exhibits memory-induced chirality while self-solidifying. The droplet swimmer can efficiently remove uranium from aqueous solutions and perform chiral motion autonomously. These findings provide a new approach to develop self-propelled agents for environmental remediation.
Article
Engineering, Environmental
Zhigang Wang, Min Li, Chunjie Yan, Jun Cao, Minghe Du, Heng Deng
Summary: This study demonstrates the self-shaping of ceramics by harnessing the shrinkage mismatch between a pre-ceramic polymer and functional components. The resulting 3D shaped ceramics exhibit excellent electrical and photothermal properties.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Hyesun Hwang, Periklis Papadopoulos, Syuji Fujii, Sanghyuk Wooh
Summary: This study introduces a novel noncontact light-driven droplet manipulation method that utilizes photothermal effect to induce Marangoni flow for droplet motion on solid surfaces. The direction of motion can be precisely controlled by changing the irradiation position, and the addition of a miscible liquid can reverse the motion direction. The authors also show that spherical droplets on liquid repellent surfaces move through a rolling mechanism instead of sliding.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Anna Yucknovsky, Benjamin B. Rich, Ariel Westfried, Boaz Pokroy, Nadav Amdursky
Summary: This study focuses on self-propelling droplet systems responsive to pH gradients, using photoacids and photobases for light-stimuli ultrafast response and control. The movement and directionality of self-propelled droplets can be controlled by introducing the photoacid/base in different ways, resulting in a rapid change in surface tension inducing movement. The high versatility and record-breaking ultrafast response to light make these systems highly attractive for various controlled cargo-carrier systems.
ADVANCED MATERIALS INTERFACES
(2021)
Article
Materials Science, Multidisciplinary
Caleb H. Meredith, Alexander C. Castonguay, Yu-Jen Chiu, Allan M. Brooks, Pepijn G. Moerman, Peter Torab, Pak Kin Wong, Ayusman Sen, Darrell Velegol, Lauren D. Zarzar
Summary: In this study, the chemomechanical framework underlying the self-propulsion of biphasic Janus oil droplets solubilizing in aqueous surfactant is uncovered. The influence of oil mixing, droplet shape, and oil solubilization rates on droplet propulsion is elucidated. Spatiotemporal control over droplet swimming speed and orientation is demonstrated through the application of thermal gradients.
Article
Mechanics
A. G. L. Williams, G. Karapetsas, D. Mamalis, K. Sefiane, O. K. Matar, P. Valluri
Summary: This study investigates the dynamics of thin volatile droplets consisting of binary mixtures on a heated substrate. The developed model accurately predicts spreading and retraction of the droplets, with experiments confirming the preferential evaporation of more volatile components driving superspreading in some cases.
JOURNAL OF FLUID MECHANICS
(2021)
Review
Mechanics
Vladimir S. Ajaev, Oleg A. Kabov
Summary: The review focuses on studying the physical mechanisms of levitating droplets over liquid-gas interfaces and dry solid surfaces. It also discusses the self-organization of levitating droplets into large arrays, nonisothermal flotation, levitation of evaporating droplets over a pool of nonvolatile liquid, and recent advances in the study of the Leidenfrost effect.
ANNUAL REVIEW OF FLUID MECHANICS, VOL 53
(2021)
Article
Chemistry, Physical
J. D. Torrenegra-Rico, A. Arango-Restrepo, J. M. Rubi
Summary: In this study, the energetic cost of formation of Janus particle structures is computed using an approach that couples particle dynamics to the evolution of fuel concentration in the medium. Different types of structures are shown to emerge, and the energy dissipated in their formation is obtained from the entropy production rate. Analyzing the free energy of these particles allows for the establishment of a thermodynamic criterion for structure formation based on the behavior of chemical potential.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Multidisciplinary Sciences
Hyunki Kim, Subramanian Sundaram, Ji-Hwan Kang, Nabila Tanjeem, Todd Emrick, Ryan C. Hayward
Summary: The article introduces a light-driven active particle platform that can reconfigure interaction geometries and build oscillator and spinner networks. Using optically induced Marangoni trapping, thermal interactions among multiple particles lead to complex coupled oscillatory and rotational motions, demonstrating collective behavior.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Chemistry, Multidisciplinary
Haodong Zhang, Fei Wang, Britta Nestler
Summary: In this study, a phase-field approach was used to investigate the formation of Janus droplets via thermally induced phase separation. The results showed that asymmetric phase separation and hydrodynamics play crucial roles in the formation and evolution of Janus droplets.
Article
Mechanics
K. Hasegawa, Y. Manzaki
Summary: The paper investigates the spreading and atomization dynamics of an aqueous 2-propanol solution on sunflower oil, demonstrating firework-like behavior caused by the Marangoni effect. It also discusses the Marangoni flow driven by temperature gradient, liquid droplet count and size distribution, as well as fingering instability and comparison with capillary model of the interface between the IPA solution and sunflower oil.
Article
Multidisciplinary Sciences
Vishal P. Patil, Joseph D. Sandt, Mathias Kolle, Jorn Dunkel
Article
Chemistry, Physical
Marko Pavlovic, Markus Antonietti, Bernhard V. K. J. Schmidt, Lukas Zeininger
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2020)
Article
Chemistry, Physical
Milena Perovic, Lukas Zeininger, Martin Oschatz
Summary: The catalytic activity of metal nanoparticles supported on porous materials is influenced by factors such as size, shape, and interaction with the support. The local environment and surface coverage of the catalyst also play a crucial role in catalytic processes. Immobilizing heterogeneous catalysts on perfluorocarbon emulsion droplets can promote oxygen delivery in aqueous phase reactions.
Article
Polymer Science
Bradley D. Frank, Markus Antonietti, Lukas Zeininger
Summary: A facile one-step approach is reported for the synthesis of polymer particles with tunable characteristics, using dynamically reconfigurable oil-in-water Janus emulsions as structural templates. The resulting particles have intrinsic Janus character and can be further functionalized, promoting directed self-assembly and alignment at fluid interfaces. Applications include technical emulsions, oil recovery, manufacturing of self-assembled architectures, and microstructured interfaces engineering.
Article
Nanoscience & Nanotechnology
Bradley D. Frank, Milena Perovic, Saveh Djalali, Markus Antonietti, Martin Oschatz, Lukas Zeininger
Summary: Janus particles have a strong tendency to directionally assemble and segregate to interfaces, offering advantages as colloidal analogues of molecular surfactants to enhance stability of multiphasic mixtures. A novel one-step synthetic approach for generating amphiphilic polymer Janus particles with highly uniform and tunable wettability contrasts has been developed, utilizing reconfigurable bi-phasic Janus emulsions as particle scaffolds. This versatile method allows for fine-tuning of internal droplet geometry and the generation of Janus particles with adjustable wettability profiles.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Analytical
Marko Pavlovic, Heman Kumar Ramiya Ramesh Babu, Saveh Djalali, Milan Vranes, Vasa Radoni, Lukas Zeininger
Summary: A novel method for monitoring mineral content of drinking water using responsive complex emulsions was reported, showing changes in droplet morphology to reflect variations in surfactant effectiveness due to metal cation addition. The study demonstrated that salt concentration and valency can influence the extent of droplet response, with divalent cations resulting in a more pronounced response. This device concept may provide a simple and cost-effective alternative for rapid monitoring of water hardness levels.
ANALYTICAL CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Saveh Djalali, Pablo Simon Marques, Bradley D. Frank, Lukas Zeininger
Summary: A synthetically minimal artificial emulsion platform has been designed in this study, capable of autonomously adapting to its chemical environment through interfacial supramolecular recognition events. The platform demonstrates programmed up- and down-regulating capabilities by selectively assembling synthesized crown ether surfactants onto anisotropic biphasic emulsion droplets. This adaptive soft material platform showcases utility in self-regulated uptake and release of metal ions, biomimetic recognition of biomolecules, and triggered surface-encoded payload release applications.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Multidisciplinary Sciences
Anthony D. McDougal, Sungsam Kang, Zahid Yaqoob, Peter T. C. So, Mathias Kolle
Summary: During metamorphosis, butterfly wings develop hundreds of thousands of scales with intricate microstructures and nanostructures, which determine the wings' optical appearance, wetting characteristics, thermodynamic properties, and aerodynamic behavior. Understanding the dynamic processes and temporal coordination required to sculpt the scales' structural features is critical for fully understanding scale formation. Continuous, in vivo imaging of growing scale cells allows for the establishment of a morphological timeline of wing scale formation and quantitative insights into the patterning and growth processes involved.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Materials Science, Multidisciplinary
Pablo Simon Marques, Bradley D. Frank, Aleksandr Savateev, Lukas Zeininger
Summary: A new approach utilizing biphasic complex emulsions as droplet-based solar concentrators is reported in this study to efficiently harvest and convey photons to photocatalytic reaction centers, resulting in a significant performance increase of a series of photocatalytic reactions under diffuse sunlight conditions.
ADVANCED OPTICAL MATERIALS
(2021)
Article
Multidisciplinary Sciences
Bradley D. Frank, Saveh Djalali, Agata W. Baryzewska, Paolo Giusto, Peter H. Seeberger, Lukas Zeininger
Summary: Researchers have achieved chemotactic motion of emulsion droplets, which can be controllably altered by modifying the droplets' geometry and composition. This finding has implications for the design of smart and adaptive microbots.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Marko Pavlovic, Markus Antonietti, Lukas Zeininger
Summary: This study demonstrates programmed and directional chemical inter-droplet communication in a network of aqueous emulsion droplets. Non-reciprocal transfer of substrates between enzyme-containing droplets is achieved through (biochemically) induced osmolarity gradients, and concentration gradients are used to direct a multistep enzymatic cascade reaction across multiple droplets.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Saveh Djalali, Bradley D. Frank, Lukas Zeininger