Hangbo Zhao | University of Southern California: Why does this liquid metal conductor become more conductive the further you stretch it?
00:08:14 - 00:09:40
Other snippets from this talk
Summary of the clip:
How do we engineer stretchable conductors that defy the fundamental geometric limits of piezoresistivity under extreme strain?
Conventional stretchable electronics suffer from severe resistance degradation under high strain. When a standard conductor is stretched tenfold, the simultaneous elongation and cross-sectional area reduction dictate a geometric resistance increase of two orders of magnitude. This predictable electromechanical behavior limits the utility of traditional carbon nanotube or metallic nanowire networks in high-strain applications.
A novel liquid metal particle thin-film system breaks this paradigm by exhibiting an anomalous, self-enhancing conductivity mechanism. Under extreme tensile deformation up to ten times its original length, the material's resistance increases by only a few fold. This counterintuitive performance indicates that the bulk material effectively becomes more conductive as it is stretched, presenting a highly stable electrical profile that outperforms conventional stretchable conductors.
The underlying physics of this phenomenon lie in strain-induced morphological transitions within the thin film. Beyond a critical strain threshold, the liquid metal particles undergo severe mechanical deformation and rupture. This localized structural failure drives the coalescence of isolated liquid metal domains, forming a highly interconnected, continuous conductive network that actively compensates for geometric path elongation.
In this short video, you can learn:
* The geometric and physical limitations that cause conventional stretchable conductors to lose conductivity under high strain.
* How liquid metal particle thin films maintain exceptionally low resistance changes even when stretched tenfold.
* The microstructural deformation and particle rupture mechanisms that drive self-enhancing conductivity.
š **Clip Abstract** The speaker discusses the anomalous electromechanical properties of a liquid metal particle thin film that exhibits extremely low resistance change when stretched up to ten times its length. He explains that while conventional conductors experience a massive resistance increase due to geometric narrowing, this material undergoes particle deformation and rupture under strain to form a more interconnected, highly conductive network.
š¤ Speaker: Hangbo Zhao
š¢ Company: University of Southern California
š
Event: Future of Electronics RESHAPED USA 2026
š Location: Computer History Museum, Mountain View, California, USA
š Learn more at the next TechBlick event: https://www.techblick.com
#LiquidMetalMicroparticles, #StretchableConductors, #StretchInducedCoalescence, #SelfHealingConductiveNetworks, #StretchableElectronics, #WearableSensors
This is a highlight of the presentation:
High-Resolution Liquid Metal-Based Stretchable Electronics Enabled By Colloidal Self-Assembly and Micro-Transfer Printing
Future of Electronics RESHAPED USA 2026
10-11 June 2026
Computer History Museum, Mountain View, California, USA
Organised By:
TechBlick
More Highlights from the same talk.
00:03:16 - 00:05:23
Can capillary forces during solvent evaporation be harnessed to achieve room-temperature "cold welding" of liquid metal microparticles?
Can capillary forces during solvent evaporation be harnessed to achieve room-temperature "cold welding" of liquid metal microparticles?
Liquid metal microparticles are inherently insulated by a native oxide skin that prevents electrical conduction. By utilizing electrostatic self-assembly, a uniform monolayer of these particles is deposited onto a substrate in a self-limiting process.
During the drying phase, the evaporation of the surrounding liquid solvent generates capillary forces on the order of hundreds of nanonewtons. This mechanical force is strong enough to rupture the nanoscale oxide skin, enabling room-temperature cold welding between adjacent gallium-based particles.
This physical mechanism was validated using atomic force microscopy (AFM) to crush individual particles and measure the exact rupture threshold. The resulting network achieves metallic-level bulk conductivity without requiring high-temperature thermal sintering.
In this short video, you can learn:
* How electrostatic charge is leveraged to assemble a self-limiting monolayer of liquid metal microparticles.
* The role of capillary force during solvent evaporation in rupturing the native insulating oxide skin.
* How AFM nano-indentation was used to measure and prove the physical threshold of oxide rupture.
š **Clip Abstract** This clip details a self-limiting electrostatic assembly method to form highly conductive liquid metal networks at room temperature. It reveals how evaporation-induced capillary forces act as the primary mechanism for breaking native oxide skins, initiating spontaneous cold welding.
š Link in comments š
#LiquidMetalMicroparticles, #ElectrostaticSelfAssembly, #CapillaryColdWelding, #OxideSkinRupture, #FlexibleElectronics, #PrintedElectronics
00:06:18 - 00:07:36
How can we pattern highly fluid, high-surface-tension liquid metals at a 5-micron resolution without vacuum deposition?
How can we pattern highly fluid, high-surface-tension liquid metals at a 5-micron resolution without vacuum deposition?
Liquid metals exhibit extremely high surface tension, making traditional lithographic and vacuum deposition methods impractical for high-resolution patterning. To bypass this, a novel hybrid approach combining fluidic self-assembly and elastomer-based transfer printing was developed.
The process initiates by self-assembling liquid metal microparticles onto a pre-patterned SU-8 template on a glass substrate. These particles are then transfer-printed onto a silicone elastomer, where the applied printing pressure drives localized mechanical sintering and particle rupture.
This technique successfully produces ultra-fine features with line widths down to 5 microns and thicknesses of only 2 to 3 microns. This combination of fine resolution and scalable transfer printing demonstrates high potential for wafer-scale manufacturing of stretchable circuits.
In this short video, you can learn:
* The micro-transfer printing workflow used to bypass the high surface tension limits of liquid metals.
* How templated SU-8 substrates enable ultra-fine alignment of microparticles before elastomeric transfer.
* The role of transfer pressure in mechanically driving secondary sintering of the patterned conductors.
š **Clip Abstract** This clip introduces a high-resolution transfer printing process that achieves 5-micron line widths in liquid metal circuits. By utilizing a templated assembly and mechanical transfer pressure, the method enables scalable, wafer-level patterning of highly stretchable electronics.
š Link in comments š
#LiquidMetalElectronics, #MicroTransferPrinting, #MechanicalSintering, #FluidicSelfAssembly, #StretchableElectronics, #PrintedElectronics