Hongmiao Tian

Xi'an Jiaotong University | XJTU · Department of Manufacturing and Control

Bioinspired dry adhesives relying on van der Waals interactions have shown great potential in object manipulation and climbing robots. Although substantial progress has been made in dry adhesives for extreme environments (such as vacuum and microgravity), robust adhesion at low temperatures, i.e., typical scenes in space or polar environments, is r...

Perching-and-takeoff robot can effectively economize onboard power and achieve long endurance. However, dynamic perching on moving targets for a perching-and-takeoff robot is still challenging due to less autonomy to dynamically land, tremendous impact during landing, and weak contact adaptability to perching surfaces. Here, a self-sensing, impact-...

Improving droplet velocity as much as possible is considered as the key to improving both printing speed and printing distance of the piezoelectric drop-on-demand inkjet printing technology. There are 3 tough and contradictory issues that need to be addressed simultaneously, namely, the actuation pressure of the piezoelectric printhead, satellite d...

The implementation of complex, high‐precision optical devices or systems, which have vital applications in the aerospace, medical, and military fields, requires the ability to reliably manipulate and assemble optical elements. However, this is a challenging task as these optical elements require contamination‐free and damage‐free manipulation and c...

Surface nanopatterning of semiconductor optoelectronic devices is recognized powerful for improving their quality and performance. However, photoelectric devices' inherent stress sensitivity and inevitable warpage pose a huge challenge on fabricating nanostructures large-scale. Electric-driven flexible-roller nanoimprint lithography for nanopattern...

The voltage outputs of flexible piezoelectric films after bending deformation have always been limited by two factors, including the incompatible polarization direction with bending strain and the interfacial fatigue failure between the piezoelectric films and the electrode layers, largely hindering the applications in wearable electronics. Herein,...

For dry adhesive-based operation, highly adaptable and stable manipulation is important but also challenging, especially for irregular objects with complex surface (such as abrupt profile and acute projection) under vibration-inducing environments. Here, a multi-scale adhesive structure, with mechanically isolated energy-absorbing backing, based on...

In the pursuit of designing fiber-reinforced composites with synergistic increased strength and toughness, a novel electric field-driven resin infiltration method is proposed. Specifically, during epoxy resin solidification, the void content of the composites is effectively reduced by 77.1%, from 2.14% to 0.49%, and the tensile strength, interlamin...

Laminated graphene film has great potential in compact high-power capacitive energy storage owing to the high bulk density and opened architecture. However, the high-power capability is usually limited by tortuous cross-layer ion diffusion. Herein, microcrack arrays are fabricated in graphene films as fast ion diffusion channels, converting tortuou...

Tunable structural color has many potential applications in artificial camouflage, mechanical sensors, etc. Despite the extensive efforts to develop efficient tunable structural color, there is still a wide gap between the existing "passive" tuning methods and the "active" strategy found on organisms such as chameleons that can change color accordi...

Artificial dry adhesives have exhibited great potential in the field of robotics. However, there is still a wide gap between bioinspired adhesives and living tissues, especially regarding the surface adaptability and switching ability of attachment/detachment. Here, we propose a sensing-triggered stiffness-tunable smart adhesive material, combining...

The piezoelectric inkjet (PIJ) printing technique, as a typical drop-on-demand (DOD) inkjet process, employs the electric potential for activating the mechanical vibration of a lead zirconium titanate (PZT) membrane. As a result, the constant flow of the fluidic ink within the solid channel is attained, resulting in the formation of a droplet in th...

The integrated perception capable of detecting and monitoring varieties of activities is one of the ultimate purposes of wearable electronics and intelligent robots. Limited by the space occupation, it lacks practical feasibility to stack multiple types of single sensors on each other. Herein, a high-sensitivity dual-function capacitive sensor with...

Translating the material merits of graphene to practical supercapacitor devices is critical for promoting capacitive energy storage, but is challenging due to the limited scalability in fabricating high‐performance graphene electrode films. Here, we demonstrate a method for fabricating graphene microsphere films, formed by the bubble‐induced destru...

Artificial muscles are of significant value in robotic applications. Rigid artificial muscles possess a strong load‐bearing capacity, while their deformation is small; soft artificial muscles can be shifted to a large degree; however, their load‐bearing capacity is weak. Furthermore, artificial muscles are generally controlled in an open loop due t...

Strain Sensing In article number 2207141, Yongsong Luo, Xiaoliang Chen, Jinyou Shao, and co‐workers propose a gated microchannel‐based strain‐sensing strategy inspired by ion channels in living organisms. Discretely distributed micropillars are introduced into fluidic channels to act as smart gates, which can nearly cut off the ion pathways during...

4-D printed structures have excellent application prospects in defense, aerospace, medical, and other fields due to their alterable shape and function. Current 4-D printed structures are limited to make predefined shape changes in response to particular external stimuli by the design of the materials and structures. However, it is crucial to achiev...

Bioinspired dry adhesives have an extraordinary impact in the field of robotic manipulation and locomotion. However, there is a considerable difference between artificial structures and biological ones regarding surface adaptability, especially for rough surfaces. This can be attributed to their distinct structural configuration and forming mechani...

Inspired by the prominent adhesion ability of octopus suckers, many dry/wet adhesives with specific micro‐structure have been fabricated for applications in smart robots, manipulators, and medical treatments. However, the reported octopus‐inspired adhesive patches are either suction‐assistant without tight‐sealing, or suction‐sealed but inefficient...

Developing highly sensitive strain sensors requires conduction pathways capable of rapidly switching between disconnection and reconnection in response to strain. Ion channels in living organisms exactly control the channel switch through protein‐composed gates, achieving changeable ion currents. Herein, inspired by the gating characteristics of th...

Human-like tactile perception is critical for promoting robotic intelligence. However, reproducing tangential “sliding” perception of human skin is still struggling. Inspired by the lateral gating mechanosensing mechanism of mechanosensory cells, which perceives mechanical stimuli by lateral tension–induced opening-closing of ion channels, we repor...

Soft robots can adapt to various unstructured environments and have received extensive attention. The integrated structure of sensing and actuation makes soft robots more miniaturized and integrated, enriching their usage scenarios. The multiple degrees of freedom of soft actuators facilitate flexible deformation but also bring challenges to precis...

The contact splitting hypothesis (CSH) has been proposed for around 20 years, which suggests that the patterned or fibrillar surfaces enable very efficient biological attachment systems (e.g., Geckos’ seta). However, there is still a debate in academic community on the necessity of the CSH in man-made adhesives, since experiments have indicated tha...

Piezoelectric drop-on-demand inkjet printing is a widely used additive manufacturing technology, in which droplets are ejected from a piezoelectric printhead under certain actuation waveforms to form three-dimensional structures. The crosstalk generated by high- frequency multi-pulse actuation waveforms in the piezoelectric printhead has always bee...

Liquid crystal elastomers (LCEs) have shown great potential as soft actuating materials in soft robots, with large actuation strain and fast response speed. However, to achieve the unique features of actuation, the liquid crystal mesogens should be well aligned and permanently fixed by polymer networks, limiting their practical applications. The re...

Creative Commons Attribution License (CC BY 4.0). Highly sensitive flexible pressure sensors play an important role to ensure the safety and friendliness during the human-robot interaction process. Microengineering the active layer has been shown to improve performance of pressure sensors. However, the current structural strategy almost relying on...

The various high aspect ratio micro/nano structures that are duplicated by the widely applicable micro/nanomolding process would require excellent wettability of the structured mold for full filling of the liquid-like materials into microcavities. Herein, by employing molecular dynamics (MD) simulations, the influence of a monolayer graphene (MLG)...

An artificial muscle capable of shape programmability, deformation-locking capacity without needing continuous external energy, and self-sensing capability is highly desirable yet challenging in applications of reconfigurable antenna, deployable space structures, etc. Inspired by coupled behavior of the muscles, bones, and nerve system of mammals,...

Front Cover In article number 2101539, Xiangming Li, Jinyou Shao, and co‐workers demonstrate a roll‐to‐roll nanoimprinting method to deform flat aluminum foils into 3D current collectors with hierarchical microstructures. The 3D current collector significantly reduces the contact resistance by an order of magnitude, which comprehensively improves t...

Electrowetting-on-dielectric (EWOD) is a versatile technique for controlling the liquid-wetting behavior of solid surfaces, but usually relies on bulky and complex power suppliers for high driving voltages, which largely limits the practical applications toward miniaturization, portability, and multifunctional integration. Here, a mechanical stimul...

The free surface of a thin polymeric film is often unstable and deforms into various micro-/nano-patterns under an externally applied electric field. This paper reviews a recent patterning technique, electrohydrodynamic patterning (EHDP), a straightforward, cost-effective and contactless bottom-up method. The theoretical and numerical studies of EH...

Solid-state supercapacitors have advantages of leakage free and flexibility but usually have low energy density at low temperature. This is largely due to the significantly declined ionic conductivity as well as the relatively low voltage window of the gel electrolytes. Here we designed a low temperature tolerant organogel electrolyte by systematic...

Reducing the contact resistance between active materials and current collectors is of engineering importance for improving capacitive energy storage. 3D current collectors have shown extraordinary promise for reducing the contact resistance, however, there is a major obstacle of being bulky or inefficient fabrication before they become viable in pr...

The interfacial shear strength between carbon fiber and polymer matrices plays a critical role in bulk mechanical performances of carbon fiber-reinforced polymer composites. However, finding simple and effective methods for modulating the interfacial adhesion remains challenging even after over a decade of research and development. Herein, a novel...

Metal Micropatterning In article number 2109265, Xiangming Li and co-workers present controllable and safe spark discharges generated by a triboelectric nanogenerator under atmosphere and offer a simple, reliable, and versatile metal micropatterning method for flexible electronics.

Flexible and stretchable conductors are critical elements for constructing soft electronic systems and have recently attracted tremendous attention. Next generation electronic devices call for self-healing conductors that can mimic the damage repairing ability of natural skins to achieve good reliability and sustainability. Herein, we report a self...

Crack-based flexible strain sensor have advantages of high sensitivity and high detection resolution, which have shown high promise for applications in human–machine interface, biological health detection, and electronic skin. However, the conductive layer in the commonly used crack-based strain sensors tends to lift off after repeatedly stressing/...

Metal micropatterns play critical roles in flexible electronics. However, the lack of versatile strategies for micropatterning of diverse metal materials on various thin, flexible or stretchable substrates has limited the rapid development of flexible electronics. Here, a metal micropatterning method by triboelectric spark discharge under atmospher...

Bioinspired structural adhesives that are capable of bonding two objects together have recently found widespread applications in industrial fields, because of their promising reusability and environmental friendliness. However, such adhesives are usually monofunctional and cannot yield real‐time detection on the adhesion status, which is important...

Flexible piezoelectric sensors have attracted much attention due to good dynamic response, high sensitivity, and self-powered sensing advantages. However, piezoelectric outputs are usually affected by temperature variation, thus limit their applications on industrial intelligent equipment. Here, a new flexible piezoelectric sensor with in situ te...

Microsupercapacitors (MSCs) are vital power sources for internet of things (IoTs) and miniaturized electronics. The performance of MSCs is often restricted by its low areal energy density, which is due to the low areal mass loading of active materials. Constructing thick planar microelectrode with fine structure and high aspect ratio is an efficien...

Polarized radiative semiconductor luminous chips have huge application potentials in lots of high value-added fields. Integrating a subwavelength grating is recognized as the most promising method for development of polarized chips, but still faces the challenge of lower polarized radiation performance. The paper proposed and developed a scattering...

Non-planar morphology is a common feature of devices applied in various physical fields, such as light or fluid, which pose a great challenge for surface nano-patterning to improve their performance. The present study proposes a discretely-supported nanoimprint lithography (NIL) technique to fabricate nanostructures on the extremely non-planar surf...

We report facile fabrication of flexible concave microlens arrays (MLAs) with a well-controlled curvature using the leaky dielectric (LD) via electrowetting-on-dielectrics (EWOD) phenomenon. MLAs with a larger curvature (up to...

Liquid-crystal elastomer (LCE)-based soft robots and devices via an electrothermal effect under a low driving voltage have attracted a great deal of attention for their ability on generating larger stress, reversible deformation, and versatile actuation modes. However, electrothermal materials integrated with LCE easily induce the uncertainty of a...

In these areas of flexible displays and wearable devices, double-sided light-emitting devices have huge commercial applications. Here, we provide a novel form of flexible double-sided light-emitting devices by designing and manufacturing different transparent interdigital electrodes for lighting the structural areas of composite emitting layers. Th...

3D printing of arbitrary shapes and unique architectures offers unparalleled flexibility and simplicity for fabrication of highly complex 3D conformal electronics. It drives up high demands in electronic materials with excellent processability and functionality simultaneously. Herein, we overcome this challenge in prepared nanofiller/polymer piezoe...

Gecko-inspired dry adhesion has been attracted much attention for many applications such as soft grippers and wall-climbing robots, which, however, demonstrates stable adhesion on flat surfaces and small adhesion on non-flat surfaces. In practice, the geckos' capability of walking upside down on both flat and non-flat surfaces comes from the combin...

In article number 2000046, Jinyou Shao and co‐workers use scalable nanoimprinting technology to fabricate a highly sensitive flexible multiplexed sensor array based on distributed piezoelectric micropillars. This sensor array is successfully applied to map the force distribution, and maintain tactility on curved surfaces, showing great potential fo...

Under the combination of the passive adhesion generated by micro/nano-structures on their feet and the active mechanical stimulus of their toe muscles, geckos can stably walk on vertical walls and horizontal ceilings. Inspired by such stimuli-responsive systems in nature, an active adhesive soft gripper stimulated by low voltage (usually ≤ 6 V), co...

The ongoing revolution of human–robot interactions and electronic skins has created new requirements for tactile sensors, including good mechanical flexibility, high sensitivity, and the availability of distributed pixels for detecting force distribution. Here, a highly sensitive flexible sensor array based on piezoelectricity‐enhanced vertically a...

Combination of high transmittance and controllable focal length for plano-convex lenses is critical for various optical systems but has been a challenge. Here we demonstrate a strategy to overcome this...

The ability of gecko climbing on rough surfaces can be attributed to the outstanding features of the “active adhesive” linked to natural coupling of toe muscles and surface adhesive structures, i.e., tuning the contact status between adhesive structures and opposite surfaces through muscles, which inspires us to firstly design active adhesive soft...

Coating hierarchical micro-nanostructures on the surface of optoelectronic devices has been demonstrated to improve the overall performance. However, fabricating desired structures on a fragile optoelectronic device substrate is still challenging. A suspended-template electric-assisted-nanoimprint technique is proposed herein to controllably fabric...

Micro-supercapacitors (MSCs) with thick interdigital microelectrodes of carbon-based materials have excellent electrochemical performance and hold tremendous promise in microscale energy storage devices. Here, a scalable strategy to fabricate thick embedded multiwalled carbon nanotubes (MWCNTs) as interdigital microelectrodes for MSCs is developed...

Geckos, which can walk upside down on smooth or rough surfaces, owe this ability to the hierarchical structures under their toes. These structures are responsible for substantial adhesion and, at the same time, for quick attachment/detachment by mechanical stimulus of toe muscles. Inspired by such stimuli‐responsive systems in nature, an active adh...

Electrochromic device is a kind of device that can produce color change under the actuation of electric signal. It has attracted wide attention because of its dynamic color change properties, color diversity and convenience of driving signals. These properties highlight its potential application prospects in dynamic display, anti-counterfeiting tre...

Stable and durable piezoelectric nanogenerators (PENGs) with good flexibility, high performance and superior radiation resistance under harsh environments are promising for space exploration. Here, a novel PENG based on P(VDF-TrFE)/boron nitride nanotubes (BNNTs) nanocomposite micropillar arrays with enhanced performance and excellent neutron radia...

A stable and uniform electric field is to be generated even though a large mechanical deformation is the primary criterion for a transparent conductive film. This study proposes a protective integrated transparent conductive film (PITCF) including indium tin oxide (ITO), a silver nanowire (Ag NW) network, and a protective polydimethylsiloxane (PDMS...

To efficiently manufacture high-aspect-ratio micro−/nanopatterns of conducting polymers (CPs) via electrohydrodynamic patterning (EHDP), a soluble oligomerpyrrole derivative was synthesized through the method of side-chain-induced solubilization. The oligomerpyrrole derivative shows a low number-average molecular weight (M n ) of 5674 due to the hi...