A5036247243- Advanced Materials and Mechanics
- Carbon Nanotubes in Composites
- Advanced Sensor and Energy Harvesting Materials
- Graphene research and applications
- Mechanical and Optical Resonators
- Additive Manufacturing and 3D Printing Technologies
- Surface Modification and Superhydrophobicity
- Acoustic Wave Resonator Technologies
- Modular Robots and Swarm Intelligence
- Additive Manufacturing Materials and Processes
- Acoustic Wave Phenomena Research
- Nonlinear Photonic Systems
- Photopolymerization techniques and applications
- Dielectric materials and actuators
- Micro and Nano Robotics
- Nanotechnology research and applications
- Magnetic Bearings and Levitation Dynamics
- Nonlinear Dynamics and Pattern Formation
- Structural Analysis and Optimization
- Supercapacitor Materials and Fabrication
- Advanced MEMS and NEMS Technologies
- Nanomaterials and Printing Technologies
- Textile materials and evaluations
- Force Microscopy Techniques and Applications
- Nanofabrication and Lithography Techniques
University of Illinois Urbana-Champaign
2016-2025
University of Cambridge
2024-2025
Bridge University
2024
Urbana University
2021-2024
Chapman University
2024
University of Illinois System
2018-2022
University of Chicago
2021
Argonne National Laboratory
2021
National Center for Supercomputing Applications
2021
CEA Grenoble
2021
Using origami folding to construct and actuate mechanisms machines offers attractive opportunities from small, scalable, cheap robots deployable adaptive structures. This paper presents the design of a bio-inspired crawling robot constructed by sheets paper. The building block structure is based on Kresling crease pattern (CP), chiral tower with polygonal base, which expands contracts through coupled longitudinal rotational motion similar screw. We have multi-stable structural equilibria can...
The mechanical behavior of high quality two-dimensional (2D) crystals offers exciting opportunities for new material design, such as the combination extremely in-plane stiffness and bending flexibility, compared to existing three-dimensional (3D) forms. By combining different 2D vertically or by stitching, unusual properties can arise due nonlinear interactions between them. Van der Waals forces stacked give rise a wide range useful phenomena layer-number dependent friction, superlubricity,...
Pump it up Carbon nanotube yarns can be used as electrochemical actuators because infiltration with ions causes a contraction in length and an expansion diameter. Either positive or negative cause this effect. Chu et al. constructed all-solid-state muscle that eliminated the need for electrolyte bath, which may expand potential its use applications. By infiltrating charged polymers, fibers start partially swollen, so increase through loss of ions. It is thus possible to overall stroke...
Millions of years evolution have allowed animals to develop unusual locomotion capabilities. A striking example is the legless-jumping click beetles and trap-jaw ants, which jump more than 10 times their body length. Their delicate musculoskeletal system amplifies muscles' power. It challenging engineer insect-scale jumpers that use onboard actuators for both elastic energy storage power amplification. Typical require a combination at least two actuator mechanisms triggering, leading complex...
A new technology called capillary forming enables transformation of vertically aligned nanoscale filaments into complex three-dimensional microarchitectures. We demonstrate carbon nanotubes diverse forms having intricate bends, twists, and multidirectional textures. In addition to their novel geometries, these structures have mechanical stiffness exceeding that microfabrication polymers, can be used as masters for replica molding. Detailed facts importance specialist readers are published...
We study synthesis of vertically aligned carbon nanotube (CNT) "forests" by a decoupled method that facilitates control the mean diameter and structural quality CNTs enables tuning kinetics for efficient growth to forest heights several millimeters. The substrate temperature (Ts) primarily determines CNT diameter, whereas independent rapid thermal treatment (Tp) C2H4/H2 reactant mixture significantly changes rate terminal height but does not change diameter. Synchrotron X-ray scattering is...
Aquatic animals like fishes and larval amphibians have flexible gills with a large surface area for gas exchange. When exposed to air, typically collapse coalesce due the elastocapillary effect, reducing exchange potentially causing death. To resist these effects, some are hypothesized evolved stiffened gills, but elastocapillarity effects not been investigated empirically or theoretically. Here, we examine deformations of artificial elastomeric gill lamellae under quasi-static dynamic...
Abstract Applications of carbon nanotubes (CNTs) in flexible and complementary metal‐oxide‐semiconductor (CMOS)‐based electronic energy devices are impeded due to typically low CNT areal densities, growth temperatures that incompatible with device substrates, challenges large‐area alignment interconnection. A scalable method for continuous fabrication transfer printing dense horizontally aligned (HA‐CNT) ribbon interconnects is presented. The process combines vertically (VA‐CNT) by thermal...
In linear time-invariant dynamical and acoustical systems, reciprocity holds by the Onsager-Casimir principle of microscopic reversibility, this can be broken only odd external biases, nonlinearities, or time-dependent properties. A concept is proposed in work for breaking dynamic based on irreversible nonlinear energy transfers from large to small scales a system with hierarchical internal structure, asymmetry, intentional strong stiffness nonlinearity. The resulting nonreciprocal...
Owing to its large electric band gap, two-dimensional (2D) hexagonal boron nitride (hBN) is a very promising candidate for making atomically thin flexible devices. Further, high mechanical strength makes it suitable as reinforcing material in composites. It thus of great interest study the strain-induced phonon shift mechanically exfoliated hBN various thicknesses under tension. found that splitting ${E}_{2g}$ two subpeaks due lifting degeneracy uniaxial loading occurs at low strain level...
Frontal ring-opening metathesis polymerization (FROMP) is a rapid, low-energy manufacturing reaction that useful for curing thermosetting materials. FROMP of dicyclopentadiene (DCPD) results in poly(dicyclopentadiene) (p(DCPD)), tough thermoset with excellent mechanical performance and chemical stability. Like most thermosets, p(DCPD) cannot be reprocessed therefore difficult to recycle. Previous work demonstrated the incorporation small quantity cleavable units strand segments networks...
A snap-through bifurcation occurs when a bistable structure loses one of its stable states and moves rapidly to the remaining state. For example, buckled arch with symmetrically clamped ends can snap between an inverted natural state as are released. standard linear stability analysis suggests that becomes unstable asymmetric perturbations. Surprisingly, our experiments show this is not always case: symmetric transitions also observed. Using experiments, numerics, toy model, we symmetry...
Twisted and coiled polymer actuators (TCPAs) generate large contractile mechanical work mimicking natural muscles, which makes them suitable for robotics health-assistive devices. Understanding the mechanism of nylon TCPA remains challenging due to interplay between their intricate geometry, chirality, residual stresses, material microstructure. This study integrates a microstructure model with rod theory analytically predict equilibrium helical shape after fabrication explain observed...
Abstract The fabrication and characterization of hybrid architectures ZnO nanowires (ZNWs) grown on organized carbon nanotubes (CNTs), by a two‐step chemical vapor deposition (CVD) process involving CNT growth from hydrocarbon source followed ZNW using Zn metal source, is reported. ZNWs grow uniformly radially individual CNTs bundles, the aligned morphology not disturbed process. nucleation crystals are analyzed in relation to classical vapor–solid mechanism. Importantly, make uniform...
Vertically-aligned carbon nanotube (CNT) "forest" microstructures fabricated by chemical vapor deposition (CVD) using patterned catalyst films typically have a low CNT density per unit area. As result, forests poor bulk properties and are too fragile for integration with microfabrication processing. We introduce new self-directed capillary densification method where liquid is controllably condensed onto evaporated from forests. Compared to prior approaches, the substrate CNTs immersed in...
While many promising applications have been demonstrated for vertically aligned carbon nanotube (CNT) forests, lack of consistency in results (e.g., CNT quality, height, and density) continues to hinder knowledge transfer commercialization. For example, it is well known that growth can be influenced by small concentrations water vapor, deposits on the reactor wall, experiment-to-experiment variations pressure within reaction chamber. However, even when these parameters are controlled during...
Natural materials such as bone and tooth achieve precisely tuned mechanical interfacial properties by varying the concentration orientation of their nanoscale constituents. However, realization control in engineered foams is limited manufacturing‐driven tradeoffs among size, order, dispersion uniformity building blocks. It demonstrated how to manufacture nanocomposite with controllable via aligned carbon nanotube (CNT) growth followed atomic layer deposition (ALD). By starting a low density...
There is a strong need for compact artificial muscles capable of applying large contractile strokes and lift heavy weights. Coiled fibers recently emerged as attractive candidates these purposes, owing to their simple construction the possibility thermal, electrical chemical actuation. An intuitive theoretical understanding mechanics actuation essential enhancement performance can pave way development new applications technologies. In this paper, complete model tensile fiber reinforced...