ORCID Profile
0000-0001-5457-3777
Current Organisation
University of Cambridge
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Springer Science and Business Media LLC
Date: 21-03-2019
DOI: 10.1038/S41467-019-09325-4
Abstract: Conductive elastic composites have been used widely in soft electronics and soft robotics. These composites are typically a mixture of conductive fillers within elastomeric substrates. They can sense strain via changes in resistance resulting from separation of the fillers during elongation. Thus, most elastic composites exhibit a negative piezoconductive effect, i.e. the conductivity decreases under tensile strain. This property is undesirable for stretchable conductors since such composites may become less conductive during deformation. Here, we report a liquid metal-filled magnetorheological elastomer comprising a hybrid of fillers of liquid metal microdroplets and metallic magnetic microparticles. The composite’s resistivity reaches a maximum value in the relaxed state and drops drastically under any deformation, indicating that the composite exhibits an unconventional positive piezoconductive effect. We further investigate the magnetic field-responsive thermal properties of the composite and demonstrate several proof-of-concept applications. This composite has prospective applications in sensors, stretchable conductors, and responsive thermal interfaces.
Publisher: American Chemical Society (ACS)
Date: 17-09-2021
Publisher: Elsevier BV
Date: 09-2020
Publisher: MDPI AG
Date: 23-05-2021
DOI: 10.3390/MI12060604
Abstract: Portability and low-cost analytic ability are desirable for point-of-care (POC) diagnostics however, current POC testing platforms often require time-consuming multiple microfabrication steps and rely on bulky and costly equipment. This hinders the capability of microfluidics to prove its power outside of laboratories and narrows the range of applications. This paper details a self-contained microfluidic device, which does not require any external connection or tubing to deliver insert-and-use image-based analysis. Without any microfabrication, magnetorheological elastomer (MRE) microactuators including pumps, mixers and valves are integrated into one modular microfluidic chip based on novel manipulation principles. By inserting the chip into the driving and controlling platform, the system demonstrates s le preparation and sequential pumping processes. Furthermore, due to the straightforward fabrication process, chips can be rapidly reconfigured at a low cost, which validates the robustness and versatility of an MRE-enabled microfluidic platform as an option for developing an integrated lab-on-a-chip system.
Publisher: IOP Publishing
Date: 24-09-2021
Publisher: MDPI AG
Date: 16-11-2022
DOI: 10.3390/NANO12224018
Abstract: Flexible pressure sensors based on polymer elastomers filled with conductive fillers show great advantages in their applications in flexible electronic devices. However, integratable high-sensitivity pressure sensors remain understudied. This work improves the conductivity and sensitivity of PDMS-Fe/Ni piezoresistive composites by introducing silver flakes and magnetic-assisted alignment techniques. As secondary fillers, silver flakes with high aspect ratios enhance the conductive percolation network in composites. Meanwhile, a magnetic field aligns ferromagnetic particles to further improve the conductivity and sensitivity of composites. The resistivity of the composite decreases sharply by 1000 times within a tiny compression strain of 1%, indicating excellent sensing performance. On the basis of this, we demonstrate an integratable miniature pressure sensor with a small size (2 × 2 × 1 mm), high sensitivity (0.966 kPa
Publisher: American Chemical Society (ACS)
Date: 28-07-2021
Publisher: Wiley
Date: 06-10-2023
Publisher: Elsevier BV
Date: 07-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9LC00482C
Abstract: Microalgae cells have been recognized as a promising sustainable resource to meet worldwide growing demands for renewable energy, food, livestock feed, water, cosmetics, pharmaceuticals, and materials. In order to ensure high-efficiency and high-quality production of biomass, biofuel, or bio-based products, purification procedures prior to the storage and cultivation of the microalgae from contaminated bacteria are of great importance. The present work proposed and developed a simple, sheathless, and efficient method to separate microalgae Chlorella from bacteria Bacillus Subtilis in a straight channel using the viscoelasticity of the medium. Microalgae and bacteria migrate to different lateral positions closer to the channel centre and channel walls respectively. Fluorescent microparticles with 1 μm and 5 μm diameters were first used to mimic the behaviours of bacteria and microalgae to optimize the separating conditions. Subsequently, size-based separation in Newtonian fluid and in viscoelastic fluid in straight channels with different aspect ratios was compared and demonstrated. Under the optimal condition, the removal ratio for 1 μm microparticles and separation efficiency for 5 μm particles can reach up to 98.28% and 93.85% respectively. For bacteria and microalgae cells separation, the removal ratio for bacteria and separation efficiency for microalgae cells is 92.69% and 100% respectively. This work demonstrated the continuous and sheathless separation of microalgae from bacteria for the first time by viscoelastic microfluidics. This technique can also be applied as an efficient and user-friendly method to separate mammalian cells or other kinds of cells.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 27-01-2023
Abstract: Materials with programmable conductivity and stiffness offer new design opportunities for next-generation engineered systems in soft robotics and electronic devices. However, existing approaches fail to harness variable electrical and mechanical properties synergistically and lack the ability to self-respond to environmental changes. We report an electro-mechano responsive Field’s metal hybrid elastomer exhibiting variable and tunable conductivity, strain sensitivity, and stiffness. By synergistically harnessing these properties, we demonstrate two applications with over an order of magnitude performance improvement compared to state-of-the-art, including a self-triggered multiaxis compliance compensator for robotic manipulators, and a resettable, highly compact, and fast current-limiting fuse with an adjustable fusing current. We envisage that the extraordinary electromechanical properties of our hybrid elastomer will bring substantial advancements in resilient robotic systems, intelligent instruments, and flexible electronics.
Publisher: AIP Publishing
Date: 15-04-2019
DOI: 10.1063/1.5086376
Abstract: Microdroplets of gallium-based liquid metal alloys have enabled various applications in the fields of biomedicine, electronics, and chemistry. However, due to the high surface tension of liquid metal, high-throughput production of uniformly sized liquid metal microdroplets is challenging using conventional acoustic or microfluidic methods. Here, adapting the submerged electrodispersion technique that has conventionally been used for generating water-based microdroplets, we develop a simple and straightforward platform for the high-throughput production of near-monodisperse (coefficient of variation less than 5%) liquid metal microdroplets in oil without using microfluidic devices. We demonstrate the capabilities of this method for producing liquid metal microdroplets (diameters ranging from tens to hundreds of micrometers) and introduce a spinning disk to induce a flow of oil phase for preventing the coalescence of the microdroplets. The simplicity and remarkable abilities demonstrated for this method may pave the path for the development of future innovative applications based on liquid metal microdroplets.
Publisher: American Chemical Society (ACS)
Date: 17-06-2020
Publisher: Wiley
Date: 13-05-2021
Abstract: Stretchable conductive composites (SCCs) are generally elastomer matrices filled with conductive fillers. They combine the conductivity of metals and carbon materials with the flexibility of polymers, which are attractive properties for applications such as stretchable electronics, wearable devices, and flexible sensors. Most conventional conductive composites that are filled with only one type of conductive filler face issues in mechanical and electrical properties. Recently, some studies introduced secondary fillers to create hybrid‐filler SCCs to solve these problems. The secondary fillers produce a synergistic effect with the primary fillers to enhance the electrical conductivity of the composites. They also improve the thermal conductivity and mechanical properties or impart composites with special functions like catalysis and self‐healing. Herein, the fabrication methods, stretchability enhancement strategies, and piezoresistivity of SCCs are analyzed, and their latest applications in stretchable electronics are introduced. Finally, the challenges and prospects of their development are discussed.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2022
Publisher: American Chemical Society (ACS)
Date: 12-02-2019
DOI: 10.1021/ACS.ANALCHEM.9B00093
Abstract: Although droplet-based microfluidics has been broadly used as a versatile tool in biology, chemistry, and nanotechnology, its rather complicated microfabrication process and the requirement of specialized hardware and operating skills hinder researchers fully unleashing the potential of this powerful platform. Here, we develop an integrated microdroplet generator enabled by a spinning conical frustum for the versatile production of near-monodisperse microdroplets in a high-throughput and off-chip manner. The construction and operation of this generator are simple and straightforward without the need of microfabrication, and we demonstrate that the generator is able to passively and actively control the size of the produced microdroplets. In addition to water microdroplets, this generator can produce microdroplets of liquid metal that would be difficult to produce in conventional microfluidic platforms as liquid metal has high surface tension. Moreover, we demonstrate that this generator can produce solid hydrogel microparticles and fibers using integrated ultraviolet (UV) light. In the end, we further explore the ability of this generator for forming double emulsions by coflowing two immiscible liquids. Given the remarkable abilities demonstrated by this platform and the tremendous potential of microdroplets, this user-friendly method may revolutionize the future of droplet-based chemical synthesis and biological analysis.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8LC00047F
Abstract: In this work, we proposed an amalgamation-assisted lithography technique using liquid metal alloys for the fabrication of complex channels with a simple fabrication process, room-temperature fabrication and low toxicity.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Guolin Yun.