Chengfeng Pan

The Chinese University of Hong Kong | CUHK · Department of Mechanical and Automation Engineering

Electrical stimulation is a promising method to modulate gastrointestinal disorders. However, conventional stimulators need invasive implantation and removal surgeries associated with risks of infection and secondary injuries. Here, we report a battery-free and deformable electronic esophageal stent for wireless stimulation of the lower esophageal...

Magnetically actuated miniature machines can perform multimodal locomotion and programmable deformations. However, they are either solid magnetic elastomers with limited morphological adapt ability or liquid material systems with low mechanical strength. Here, we report magnetoactive phase transitional matter (MPTM) composed of magnetic neodymium-i...

At the millimeter scale and in the intermediate Reynolds number ( Re) regime, the midge and mosquito larvae can reach swimming speeds of more than one body length per cycle performing a “figure eight” gait, in which their elongated bodies periodically bend nearly into circles and then fully unfold. To elucidate the propulsion mechanism of this cycl...

The geometric reconfigurations in three-dimensional morphable structures have a wide range of applications in flexible electronic devices and smart systems with unusual mechanical, acoustic, and thermal properties. However, achieving the highly controllable anisotropic transformation and dynamic regulation of architected materials crossing differen...

At the millimeter scale and in the intermediate Reynolds number (Re) regime, the midge and mosquito larvae can reach swimming speeds of more than one body length per cycle performing a "figure-of-8" gait, in which their elongated bodies periodically bend nearly into circles and then fully unfold. To elucidate the propulsion mechanism of this cycle...

Liquid metal embedded elastomers (LMEEs) are composed of a soft polymer matrix embedded with droplets of metal alloys that are liquid at room temperature. These soft matter composites exhibit exceptional combinations of elastic, electrical, and thermal properties that make them uniquely suited for applications in flexible electronics, soft robotics...

Tactile recognition is among the basic survival skills of human beings, and advances in tactile sensor technology have been adopted in various fields, bringing benefits such as outstanding performance in manipulating objects and general human-robot interactions. However, promoting enhanced perception of the existing tactile sensors is limited by th...

Deformability and self-adaptability are important for soft robots to deal with uncertain and varying situations and environments during movement and navigation. Droplet-based robots are great candidates to travel inside narrow and constrained spaces without damaging the interfaces due to their extreme deformability and liquid nature, which enables...

Intelligent magnetic soft robots capable of programmable structural changes and multifunctionality modalities depend on material architectures and methods for controlling magnetization profiles. While some efforts have been made, there are still key challenges in achieving programmable magnetization profile and creating heterogeneous architectures....

Deformability and self-adaptability are important for soft robots in order to deal with uncertain and varying situations and environments during movement and navigation. Droplet-based robots are great candidates to travel inside narrow and constrained spaces without damaging the interfaces due to their extreme deformability and liquid nature, which...

The efficient motility of invertebrates helps them survive under evolutionary pressures. Reconstructing the locomotion of invertebrates and decoupling the influence of individual basic motion are crucial for understanding their underlying mechanisms, which, however, generally remain a challenge due to the complexity of locomotion gaits. Herein, we...

This paper presents a radio-frequency (RF) based assistive technology for voice impairments (i.e., dysphonia), which occurs in an estimated 1% of the global population. We specifically focus on acquired voice disorders where users continue to be able to make facial and lip gestures associated with speech. Despite the rich literature on assistive te...

Octopus suckers that possess the ability to actively control adhesion through muscle actuation have inspired artificial adhesives for safe manipulation of thin and delicate objects. However, the design of adhesives with fast adhesion switching speed to transport cargoes in confined spaces remains an open challenge. Here, we present an untethered ma...

Biological systems with the capabilities of multi-stimuli response and delicate structural changes have inspired the design of soft actuators and robots by either creating anisotropic elements within actuators or patterning site-specific elements on layered actuators. However, introducing these two strategies into one soft actuator has not been wel...

A Correction to this paper has been published: https://doi.org/10.1038/s41928-021-00571-3.

Hydrogels offer tissue-like compliance, stretchability, fracture toughness, ionic conductivity and compatibility with biological tissues. However, their electrical conductivity (<100 S cm⁻¹) is inadequate for digital circuits and applications in bioelectronics. Furthermore, efforts to increase conductivity by using hydrogel composites with conducti...

Soft composites that use droplets of gallium‐based liquid metal (LM) as the dispersion phase have the potential for transformative impact in multifunctional material engineering. However, it is unclear whether percolation pathways of LM can support high electrical conductivity in a wide range of matrix materials. This issue is addressed through an...

Progress in soft and stretchable electronics depends on energy sources that are mechanically compliant, elastically deformable, and renewable. Energy harvesting using triboelectric nanogenerators (TENGs) made from soft materials provides a promising approach to address this critical need. Here, an elastomeric composite is introduced with sedimented...

Soft robots represent an emerging class of biologically-inspired machines that are primarily composed of elastomers, fluids, and other forms of soft matter. Current examples include crawling and swimming robots that exhibit the mobility, mechanical compliance, and deformability of various classes of soft biological organisms, ranging from cephalopo...

This paper presents an RF-based assistive technology for voice impairments (i.e., dysphonia), which occurs in an estimated 1% of the global population. We specifically focus on acquired voice disorders where users continue to be able to make facial and lip gestures associated with speech. Despite the rich literature on assistive technologies in thi...

Elastomers embedded with droplets of liquid metal (LM) alloy represent an emerging class of soft multifunctional composites that have potentially transformative impact in wearable electronics, biocompatible machines, and soft robotics. However, for these applications it is crucial for LM alloys to remain liquid during the entire service temperature...

We introduce an elastomer composite filled with silver (Ag) flakes and Ag-coated poly(dimethylsiloxane) (PDMS) beads that exhibits electrical conductivity that is two orders of magnitude greater than elastomers in which the same concentration of Ag filler is uniformly dispersed. In addition to the dramatic enhancement in conductivity, these composi...

Significance Research in soft robotics and wearable technologies has led to increasing demand for shape-changing materials that can be powered with portable electronics. Liquid crystal elastomers (LCEs) are a promising functional material for these applications but lack the electrical and thermal conductivity required for electrically stimulated sh...

Eutectic gallium indium (EGaIn) is a liquid metal alloy at room temperature. EGaIn microdroplets can be incorporated into elastomers to fabricate highly stretchable, mechanically robust, soft multifunctional composites with high thermal stability¹ and electrical conductivity2–4 that are suitable for applications in soft robotics and self-healing el...

Stretchable high‐dielectric‐constant materials are crucial for electronic applications in emerging domains such as wearable computing and soft robotics. While previous efforts have shown promising materials architectures in the form of dielectric nano‐/microinclusions embedded in stretchable matrices, the limited mechanical compliance of these mate...

A material architecture and laser-based microfabrication technique is introduced to produce electrically conductive films (sheet resistance = 2.95 Ω sq−1; resistivity = 1.77 × 10−6 Ω m) that are soft, elastic (strain limit >100%), and optically transparent. The films are composed of a grid-like array of visually imperceptible liquid-metal (LM) line...

Electrofluidic devices have attracted tremendous interest in the fields of biology, chemistry and medicine. A laser-induced plasma-assisted ablation (LIPAA) combined with successive electroplating was proposed to fabricate the electrofluidic devices in a fast and cost-effective way. LIPAA can form micro-channels and sputter coat a graphite pattern...

Micro-needle electrodes (MEs) have attracted more and more attention for monitoring physiological electrical signals, including electrode-skin interface impedance (EII), electromyography (EMG) and electrocardiography (ECG) recording. A magnetization-induced self-assembling method (MSM) was developed to fabricate a microneedle array (MA). A MA coate...

A novel micro-needle array electrode (MAE) fabricated by thermal drawing and coated with Ti/Au film was proposed for bio-signals monitoring. A simple and effective setup was employed to form glassy-state poly (lactic-co-glycolic acid) (PLGA) into a micro-needle array (MA) by the thermal drawing method. The MA was composed of 6 × 6 micro-needles wit...

Worker honeybee pierces animal or human skin with its ultra-sharp stinger and injects venom to defend itself. The insertion behavior is a painless transdermal drug delivery process. In this study, Apis cerana cerana worker honeybee was chosen as the research object. The geometry and structure of the stinger were observed by the Scanning Electron Mi...

This Medical needle plays an important role in modern clinical medicine. The penetration and pull process of medical injection needle was simulated by FEM software Abaqus, and the equivalent stress and strain were analyzed. Self-developed mechanical loading equipment was adopted to test the penetration force with different needle tip angles, needle...

Magnetization-induced self-assembly method (MSM) was proposed to fabricate micro-needle array (MA). Curable magnetic fluid droplet array was extruded from the holes of perforated mask and meanwhile drawn to form the MA shape by magnetic force. MA was heated and cross linking solidified. The formation mechanism of magnetization-induced self-assembly...