Periodic Reporting for period 1 - LUCiD-Mater (Liquids Under Confinement In 2D-MATERials)
Periodo di rendicontazione: 2020-09-21 al 2022-09-20
What is the problem/issue being addressed?
Two-dimensional (2D) materials are a relatively new class of thin materials consisting of a single layer of covalently bonded atoms. The unprecedented characteristics of 2D materials have already led to the observation of new physics and lend themselves to a wide range of technology-focused applications. Both in the fabrication process and in applications, liquids frequently interact with 2D materials. Due to the small length scales associated with these scenarios, the van der Waals (vdW) interaction between different subjects (such as between the thin solid and the substrate and between the thin liquid and the substrate) plays a crucial role in determining the final state of the system. The key scientific problem this project is focusing on is how thin solids and thin liquids are deformed at small scales in the presence of vdW interactions. In particular, motivated by recent experiments, we addressed two sub-problems: (1) the statics and dynamics of droplets on thin liquids that behave as a lubricating layer on solid substrates; (2) the equilibrium of thin sheets on adhesive substrates with liquids trapped at the interface.
Why is it important for society?
The analysis of these problems not only provides new insights into the controlling mechanisms in different systems but also suggests new methods through which the presence of thin liquids/droplets can be controlled and exploited in relevant applications that are important for society.
For example, a relevant application for problem 1 is liquid-infused surfaces (LISs) formed by coating surface with a thin layer of oil lubricant. This liquid coating has found a variety of applications including the creation of surfaces that are anti-biofouling, anti-icing and facilitate water harvesting. In many of these applications, the deformation of the lubricant surface caused by a droplet is particularly important while our analysis of problem 1 can provide direct controlling parameters on how large this deformation can be as well as how fast the completion of this deformation takes. A relevant application for problem 2 is the coupling between strain and electronic properties in graphene bubbles, which has been found to produce pseudomagnetic fields (PMFs) of magnitudes on the order of 100 Tesla. Such gigantic PMFs might be used for the design of valley filtering and valley splitting devices. Our analysis of problem 2 can be directly used to predict the shape and size of the bubble by balancing the elastic forces due to the thin sheets and van der Waals forces. Such predictions are useful for the deterministic design of graphene bubbles for relevant valley filtering and valley splitting devices.
What are the overall objectives?
The research objective of this project is to develop theoretical frameworks within which problem1 and 2 can be addressed. Particularly central to our objective is to elucidate the statics and dynamics of the competition between elasticity of 2D materials and substrates, liquid viscosity and capillarity, and interfacial vdW interactions. The training objective of this project is to allow the fellow to gain extensive scientific competence in the area of thin film mechanics by the implementation of this project.
Conclusions of the action
This project aims to understand the deformation of thin solids and thin liquids at small scales where van der Waals forces are particularly important. Based on recent experiments on LISs and graphene bubbles, this project focuses on two specific problems: the statics and dynamics of droplets on LISs and the competition between elasticity and vdW interactions in graphene bubbles.
Two-dimensional (2D) materials are a relatively new class of thin materials consisting of a single layer of covalently bonded atoms. The unprecedented characteristics of 2D materials have already led to the observation of new physics and lend themselves to a wide range of technology-focused applications. Both in the fabrication process and in applications, liquids frequently interact with 2D materials. Due to the small length scales associated with these scenarios, the van der Waals (vdW) interaction between different subjects (such as between the thin solid and the substrate and between the thin liquid and the substrate) plays a crucial role in determining the final state of the system. The key scientific problem this project is focusing on is how thin solids and thin liquids are deformed at small scales in the presence of vdW interactions. In particular, motivated by recent experiments, we addressed two sub-problems: (1) the statics and dynamics of droplets on thin liquids that behave as a lubricating layer on solid substrates; (2) the equilibrium of thin sheets on adhesive substrates with liquids trapped at the interface.
Why is it important for society?
The analysis of these problems not only provides new insights into the controlling mechanisms in different systems but also suggests new methods through which the presence of thin liquids/droplets can be controlled and exploited in relevant applications that are important for society.
For example, a relevant application for problem 1 is liquid-infused surfaces (LISs) formed by coating surface with a thin layer of oil lubricant. This liquid coating has found a variety of applications including the creation of surfaces that are anti-biofouling, anti-icing and facilitate water harvesting. In many of these applications, the deformation of the lubricant surface caused by a droplet is particularly important while our analysis of problem 1 can provide direct controlling parameters on how large this deformation can be as well as how fast the completion of this deformation takes. A relevant application for problem 2 is the coupling between strain and electronic properties in graphene bubbles, which has been found to produce pseudomagnetic fields (PMFs) of magnitudes on the order of 100 Tesla. Such gigantic PMFs might be used for the design of valley filtering and valley splitting devices. Our analysis of problem 2 can be directly used to predict the shape and size of the bubble by balancing the elastic forces due to the thin sheets and van der Waals forces. Such predictions are useful for the deterministic design of graphene bubbles for relevant valley filtering and valley splitting devices.
What are the overall objectives?
The research objective of this project is to develop theoretical frameworks within which problem1 and 2 can be addressed. Particularly central to our objective is to elucidate the statics and dynamics of the competition between elasticity of 2D materials and substrates, liquid viscosity and capillarity, and interfacial vdW interactions. The training objective of this project is to allow the fellow to gain extensive scientific competence in the area of thin film mechanics by the implementation of this project.
Conclusions of the action
This project aims to understand the deformation of thin solids and thin liquids at small scales where van der Waals forces are particularly important. Based on recent experiments on LISs and graphene bubbles, this project focuses on two specific problems: the statics and dynamics of droplets on LISs and the competition between elasticity and vdW interactions in graphene bubbles.
We have made progress to address the problems we proposed and summarized the result by writing two manuscripts correspondingly: The manuscript for problem 1 has been accepted on May 2, 2022, for publication in Physical Review Fluids and is now in press; The manuscript for problem 2 has been submitted to the International Journal of Solids and Structures on Jan 1, 2022, and is now under review. A number of activities have been carried out for the purpose of dissemination and communication, including a presentation at an international conference and four presentations at academic events.
Specifically, the results of the manuscript for problem 1 have been presented in a departmental seminar at the University of Oxford as well as APS March Meeting (an internationally established conference) virtually. The manuscript has been accepted for publication in Physical Review Fluids with the copy available in arXiv:2112.12188v2. In addition, we have deposited the data for the manuscript in the University of Oxford’s online repository ORA so that the theoretical and numerical modeling files (e.g. MATLAB scripts and numerical data) are available to the public at https://ora.ox.ac.uk/objects/uuid:a68a9057-39b4-4b38-8ea4-20bd5ee02c3c(si apre in una nuova finestra). Note that this repository link will be further linked to the manuscript on the fellow’s website and the arxiv page of this work once the DOI of this work is published in Physical Review Fluids. The results of the manuscript for problem 2 have been presented in a departmental seminar at the Peking University of Oxford and a center seminar at the University of Pennsylvania virtually. The manuscript has been submitted for publication in the International Journal of Solids and Structures with the copy available in arXiv:2202.07126. We will deposit the data for the manuscript on GitHub once the manuscript is accepted so that the theoretical and numerical modeling files (e.g. MATLAB scripts and numerical data) are available to the public.
Specifically, the results of the manuscript for problem 1 have been presented in a departmental seminar at the University of Oxford as well as APS March Meeting (an internationally established conference) virtually. The manuscript has been accepted for publication in Physical Review Fluids with the copy available in arXiv:2112.12188v2. In addition, we have deposited the data for the manuscript in the University of Oxford’s online repository ORA so that the theoretical and numerical modeling files (e.g. MATLAB scripts and numerical data) are available to the public at https://ora.ox.ac.uk/objects/uuid:a68a9057-39b4-4b38-8ea4-20bd5ee02c3c(si apre in una nuova finestra). Note that this repository link will be further linked to the manuscript on the fellow’s website and the arxiv page of this work once the DOI of this work is published in Physical Review Fluids. The results of the manuscript for problem 2 have been presented in a departmental seminar at the Peking University of Oxford and a center seminar at the University of Pennsylvania virtually. The manuscript has been submitted for publication in the International Journal of Solids and Structures with the copy available in arXiv:2202.07126. We will deposit the data for the manuscript on GitHub once the manuscript is accepted so that the theoretical and numerical modeling files (e.g. MATLAB scripts and numerical data) are available to the public.
Our corresponding manuscripts on problem 1 and problem 2 have built the corresponding theoretical framework that considered the important effect of vdW forces on the deformation of thin solids and thin liquids. These results highlighted some important subtleties such as the volume of the liquid layer in problem 1 and the wrinkling of the thin sheet in problem 2 that were ignored in the literature.
Impact on the future career prospects of the fellow. This fellowship has provided the fellow with opportunities for in-depth investigation of an increasingly important research area (the mechanics of thin films and liquids) through the LUCiD-Mater project. Benefiting from the complementarity of the project to the fellow’s current expertise, the fellow has deepened and broadened his perspectives in the generic field of thin film materials. During this fellowship, the fellow obtained a faculty position at Peking University (one of the best universities in China) and is now able to expand his research directions and approaches on his early career path.
Potential impacts. Since the two works have not been published online yet, the socio-economic impact and the wider societal implications of the project are limited so far. However, in the scientific fields, we expect that our theoretical framework could be extended for the study of more general cases. We expect the potential impact of these results in applications such as improved water harvesting efficiency by lubricant infused surfaces and improved sensitivity of pressure sensors made of 2D material bubbles. We also expect that these results will contribute to European scientific competitiveness in the fields of 2D materials and, more broadly, thin-film materials where the EU currently occupies a prominent position.
Impact on the future career prospects of the fellow. This fellowship has provided the fellow with opportunities for in-depth investigation of an increasingly important research area (the mechanics of thin films and liquids) through the LUCiD-Mater project. Benefiting from the complementarity of the project to the fellow’s current expertise, the fellow has deepened and broadened his perspectives in the generic field of thin film materials. During this fellowship, the fellow obtained a faculty position at Peking University (one of the best universities in China) and is now able to expand his research directions and approaches on his early career path.
Potential impacts. Since the two works have not been published online yet, the socio-economic impact and the wider societal implications of the project are limited so far. However, in the scientific fields, we expect that our theoretical framework could be extended for the study of more general cases. We expect the potential impact of these results in applications such as improved water harvesting efficiency by lubricant infused surfaces and improved sensitivity of pressure sensors made of 2D material bubbles. We also expect that these results will contribute to European scientific competitiveness in the fields of 2D materials and, more broadly, thin-film materials where the EU currently occupies a prominent position.