Department of Materials Science and Engineering

Permanent URI for this collectionhttps://hdl.handle.net/1807/89335

The Department of Materials Science and Engineering is one of the top ranked departments in North America. Our Professors are widely recognized both nationally and internationally for their research and scholarship in a wide range of materials science and engineering specializations. Our mission is to educate women and men for careers which build upon advanced technical knowledge in the field of Materials Science and Engineering so as to cover the complete spectrum of knowledge involving production, processing, structure, properties, performance, manufacturing and design of all classes of materials such a metals, ceramics, polymers and composites.

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TiO2-NGQD composite photocatalysts with switchable photocurrent response
(2023-01-20) Lawrence, Reece T; Croxall, Mark P; Lu, Cheng; Goh, M Cynthia
A series of titanium dioxide-nitrogen doped graphene quantum dot (TiO2-NGQD) composite photocatalysts were synthesized through a simple hydrothermal reaction with varied NGQD content. Through a proposed Z-Scheme heterojunction, the composites were able to achieve increased photocurrent generation and photocatalytic degradation of phenol under both full spectrum and visible only illumination. The prepared composites were able to switch from anodic to cathodic photocurrent by changing the light source from full spectrum to visible wavelengths. The photocatalytic capabilities of the composites were tested by degrading phenol and this was monitored via nuclear magnetic resonance. All composites outperformed the commercial standard P25 TiO2 under both full spectrum and visible irradiation, with the 8 wt% NGQD composite showing a visible improvement of over 600% compared to P25. With the ability to manipulate the generation of majority charge carriers, TiO2-NGQDs have significant potential not only in photocatalysis, but in far reaching applications such as energy harvesting and water splitting.
Dynamic Modeling and Electrical Characterization of a Heaving Hybrid Triboelectric-Electromagnetic Energy Harvester
(ASME, 2018) Saadatnia, Zia; Esmailzadeh, Ebrahim; Naguib, Hani E.
In this study the dynamic and electrical performance of a novel hybrid Electromagnetic-Triboelectric energy harvester is studied. The mechanism incorporates a linear tubular electromagnetic (EMG) transducer as well as a free-standing grating triboelectric (TENG) transducer. The heaving of the slider inside the stator triggers both EMG and TENG which results in electricity generation. The dynamic model of the system is firstly developed and the system response under external excitation is carried out. Then, the electrical output characteristics of each harvesting unit are developed based on the dynamic response. Then, the effects of various parameters such as frequency of excitation and external electrical load on the output performance of the harvester including voltage, current, and power density of the EMG and TENG units are investigated. This study provides a guideline toward the design and analysis of novel mechanical energy harvesters.
Performance-enhanced triboelectric nanogenerator using polyimide aerogel for energy harvesting and sensing
(SPIE, 2018) Naguib, Hani E.; Esmailzadeh, Ebrahim; Ghaffari, Shahriar; Saadatania, Zia
Triboelectric Nanogenerator (TENG) is a novel technology to convert mechanical energy into electricity for energy harvesting and sensing applications. Therefore, developing high performance TENG systems for practical applications is a very important and attractive topic. This study presents an efficient and extra light-weight TENG device using polyimide aerogel as the main electricity generation component. The small size porosity of the selected material will significantly change the effective dielectric thickness as well as the contact area resulting in the improvement of the TENG electrical output. The performance of proposed porous system in comparison with a system with compressed polyimide layer is evaluated to show the advantage of used aerogel. In addition, the electrical outputs of the enhanced device under different mechanical and electrical conditions are studied. Through the material fabrication and implementation, the proposed TENG can be successfully employed to boost the performance of various TENG-based energy harvesters and self-powered sensors.
3D printing complex lattice structures for permeable liver phantom fabrication
(2018) Low, Linda; Ramadan, Sherif; Coolens, Catherine; Naguib, Hani E.
Liver cancer is currently the third deadliest cancer in the world, affecting over 700,000 people per year. To improve early detection of tumours, perfusion testing is used for imaging of blood flow in the liver. Creating a phantom to accurately mimic the liver in imaging techniques such as Dynamic Contrast-enhanced (DCE) computed tomography (CT) will improve testing and calibration of different imaging protocols and pharmacokinetic perfusion models. In current literature, there lacks a permeable, easily producible and reusable liver phantom for dynamic contrast-enhanced CT perfusion testing. This study details the production of phantoms with controllable permeability for standardization in hepatic perfusion using commercially available 3D printing methods. Phantoms with hexagonal channels were designed in nTopology Element and printed in materials with a density of 0.9–1.5 g/cm3. Polylactic acid was selected for fused deposition modelling (FDM), while proprietary resins were used for an inkjet printing process called MultiJet Printing (MJP). Permeability tests were performed on samples to observe flow rates obeying Darcy's Law. Scanning electron microscopy (SEM) was used to analyze pore size in FDM and MJP samples, while micro-CT scans were performed to analyze pore interconnectivity. The collected permeability data exceeds reported literature values of 0.0167 mL s−1 cm2 and approach the desired range of 0.15–0.3 mL s−1 cm2. Micro-CT scans show obstructions from the MJP printing process. SEM images were analyzed in Fiji and showed varying results for FDM printing. Future work will involve reducing pore size while maintaining high permeability. Using 3D printing in phantom development will help create adaptable, reliable and permeable phantoms for diagnostic imaging.
Design, simulation, and experimental characterization of a heaving triboelectric-electromagnetic wave energy harvester
(Elsevier, 2018) Saadatnia, Zia; Esmailzadeh, Ebrahim; Naguib, Hani E.
Hybridization of triboelectric (TENG) and electromagnetic (EMG) generators has recently shown to be an effective approach toward harvesting water wave energy. Therefore, it is critical to develop efficient hybrid TENG-EMG designs for this application. This paper presents a hybrid TENG-EMG energy harvester based on heaving wave-energy point absorber which can be potentially used for harvesting energy of waves. The design employs linear tubular EMG unit in conjunction with grating structured freestanding mode TENG. The mechanism of a heaving buoy is taken into the account to apply the energy of water waves into the harvester. The adopted EMG mechanism is a relatively simple and highly efficient configuration and the freestanding grating TENG is very effective due to the use of multiple segments and fixed electrodes. Initially, the working mechanism of the device is theoretically simulated to show the practicality of the design. Then, the output performance of the fabricated device is fully investigated under various dynamical experiments. The energy output capability of the proposed device is demonstrated considering different electrical loads. Accordingly, the phase 1, phase 2, and phase 3 of the EMG part obtains the maximum average power density of , and , respectively. Also, the TENG unit achieves the maximum average power density of . Finally, the practical application of the hybrid system for charging storage units, lighting light-emitting diodes, and powering a sensor is proved. In fact, the proposed device offers a very cost-effective, simple structure, and effective system which is potentially useful for the blue energy extraction.
Finite-Difference Time-Domain Modeling of Periodic Structures: A review of constant wave vector techniques
(2022) Kogon, Aaron J.; Sarris, Costas D.
This article reviews state-of-the-art periodic boundary conditions (PBCs) in finite difference time-domain (FDTD) simulations that operate by enforcing constant wave vector components. The mathematical principles and 3D FDTD implementation details are systematically outlined. Techniques for extracting scattering parameters, Brillouin diagrams, and attenuation constants are presented along with the array scanning method (ASM) used to model the interaction of nonperiodic sources with periodic structures. Through these techniques, the robustness, utility, and efficiency of PBCs are demonstrated and a unified view of the various approaches to the FDTD implementation of PBCs is presented.
An Expedient Approach to FDTD-based Modeling of Finite Periodic Structures
(2020-08-31) Aaron J. Kogon; Costas D. Sarris
This paper proposes an efficient FDTD technique for determining electromagnetic fields interacting with a finite-sized 2D and 3D periodic structures. The technique combines periodic boundary conditions---modelling fields away from the edges of the structure---with independent simulations of fields near the edges of the structure. It is shown that this algorithm efficiently determines the size of a periodic structure necessary for fields to converge to the infinitely-periodic case. Numerical validations of the technique illustrate the savings concomitant with the algorithm.
A hybrid piezoelectric-triboelectric generator for low-frequency and broad-bandwidth energy harvesting
(2018) Li, Zhongjie; Saadatnia, Zia; Yang, Zhengbao; Naguib, Hani
In this paper, we report a hybrid generator to harness energy from low-frequency ambient vibrations. The generator is designed with a piezoelectric energy harvester (PEH) patch, a triboelectric nanogenerator (TENG) patch, a spring-mass system and an amplitude limiter. The spring-mass system receives energy from excitations and applies forces to the piezoelectric element and the triboelectric layers. The unique amplitude limiter is deliberately introduced into the system, not only achieving the desired frequency up-conversion effect, but also boosting the voltage responses significantly. The limiter also causes hardening nonlinearity and dynamic bifurcation triggering superharmonic resonance so that the generator resonates at a frequency of about 3 Hz. Furthermore, the proposed PEH adopts the strong compressive operation mode, and employs a truss mechanism to effectively amplify the impact forces. In experiments, open-circuit voltages are 58.4 V from PEH and 60 V from TENG under an excitation of 1.0 g at resonance. The hybridized generator is capable of achieving a maximum power of 19.6 mW from the two sources with matched impedances. The working bandwidths of the PEH and the TENG reach up to 5.39 Hz and 7.25 Hz, respectively, out of our targeted frequency domain [2.5 Hz, 10 Hz] due to the multiple resonances and nonlinearity. In the applications to charge capacitors, the high saturation voltage and relatively short charging time validate the effectiveness of our power management technique. Furthermore, the generator proves to be able to effectively scavenge energy from human body motions and charge a capacitor of 4.7 μF to 7.6 V in around 50 s, which indicates a great potential of practical applications in wearable devices.
A High Performance Triboelectric Nanogenerator Using Porous Polyimide Aerogel Film
(2019-02-04) Saadatnia, Zia; Mosanenzadeh, Shahriar Ghaffari; Esmailzadeh, Ebrahim; Naguib, Hani E
This paper presents a novel aerogel-based Triboelectric Nanogenerator (TENG) which shows a superior performance for energy harvesting and sensing applications. Polyimide-based aerogel film with varying open-cell content level is developed to be used as the main contact material for the TENG. The fabricated aerogel film is fully characterized to reveal the chemical and mechanical properties of the developed material. It is shown the use of Polyimide aerogel film remarkably enhances the performance of the TENG compared to a TENG with fully dense Polyimide layer with no porosity. This enhancement is due to the increase on the effective surface area, charge generation inside the open-cells of the aerogel, and increase on the relative capacitance of the TENG device. The effect of varying porosity from zero to 70% of open-cell content reveals that the aerogel film with 50% shows the highest performance where the peak open-circuit voltage of 40V and peak short-circuit current of 5 μA are obtained. These values are higher than those of the TENG with simple Polyimide layer with an order of magnitude. Finally, the performance of proposed TENG under resistive loads and capacitors are tested. Thus, this work presents an effective method for high performance TENG.
Effect of revolute joint mechanism on the performance of cantilever piezoelectric energy harvester
(IOP, 2019) Li, Zhongjie; Naguib, Hani E
In this paper, we present a novel method to improve the electric performance of cantilever piezoelectric energy harvesters (PEHs), i.e. by embedding the revolute joint mechanism. The harvester is usually fastened onto a host structure via one edge of the substrate. The embedment substitutes part of the edge, forming a discontinuous boundary condition. The joint mechanism greatly reduces the stiffness and damping factor of the harvester and thus increases the resonant intensity. This leads to larger deformation of the piezoelectric component and higher voltage output. We investigated mainly four cases in terms of the length of the joint by modeling for numerical solutions, and by fabricating prototypes for experimental validation. Both numerical and experimental results of the hinged cases, which agree with each other quite well, indicate that the output voltage of the PEH is up to 2.94 times as high as that of the counterpart case (full clamped or non-hinged). Furthermore, the output power is escalated by more than 670%. With no additional mass or volume added into the structure, the power density is improved by the same magnitude. In terms of applications, the hinged harvester displays much better charging performance with a higher charging rate and saturation voltage. This study can be of great significance to evidently boost the electric yields of cantilever PEHs.
Structure to Properties Relations of BPDA and PMDA Backbone Hybrid Diamine Polyimide Aerogels
(Elsevier, 2002-02-12) Mosanenzadeh, Shahriar Ghaffari; Saadatnia, Zia; Shi, Feng; Park, Chul B.; Naguib, Hani E.
A series of aromatic diamines were polymerized with two aromatic dianhydrides, pyromellitic dianhydride and 3,3′,4,4′-biphenyltetracarboxylic dianhydride, and the resulting poly(amic acid)s were thermally cyclodehydrated to aromatic polyimides. The polyimides were characterized by determining the glass transition temperatures (Tg), thermal stability, coefficients of thermal expansion, and wide-angle X-ray diffraction. Structure–property relationships are elucidated and discussed in terms of the structural fragments in the polymer chain. The PMDA-based polyimides generally revealed a higher Tg than the corresponding BPDA-based analogues. Generally, the dilution of the imide content by the insertion of oxyphenylene segments into the diamines significantly reduced the Tg. The introduction of m- or o-phenylene units into the polymer backbone usually resulted in a decrease in Tg. The attachment of pendant groups on the backbone may lead to decreased or increased Tgs, depending on the structure of pendant groups. As evidenced by X-ray diffraction, the polyimides derived from rigid, rod-like diamines or the diamines having two or three p-oxyphenylene showed a higher crystalline tendency. The presence of aliphatic pendant groups slightly reduced the thermal stability of the polyimides. The other structural changes did not show a dramatic influence on the thermal stability. Some polyimides obtained from p- or m-phenylenediamine had low thermal expansion coefficients below C−1.
Shape programming of polymeric based electrothermal actuator (ETA) via artificially induced stress relaxation
(2019-08-07) Sun, Yu-Chen; Leaker, Benjamin D; Lee, Ji Eun; Nam, Ryan; Naguib, Hani E
Electrothermal actuators (ETAs) are a new generation of active materials that can produce different motions from thermal expansion induced by Joule heating. It is well-known that the degree of deformation is determined by the amount of Joule heating and the coefficient of thermal expansion (CTE) of the material. Previous works on polymeric ETAs are strongly focused on increasing electrical conductivity by utilizing super-aligned carbon nanotube (CNT) sheets. This allows greater deformation for the same drive voltage. Despite these accomplishments with low-voltage actuation, many of the ETAs were constructed to have basic geometries such as a simple cantilever shape. In this paper, it was discovered that shape of polymeric ETA can be programmed into a desired configuration by applying an induced stress relaxation mechanism and post secondary curing. By utilizing such effects, an ETA can be programmed into a curled resting state which allows the actuator to achieve an active bending angle over 540°, a value far greater than any previous studies. This shape programming feature also allows for tailoring the actuator configuration to a specific application. This is demonstrated here by fabricating a small crawling soft robot similar to mimic an inchworm motion.
Hybrid Electroactive Shape Memory Polymer Composites with Room Temperature Deformability
(2019) Sun, Yu‐Chen; Chu, Marco; Huang, Morris; Hegazi, Omer; Naguib, Hani E.
Polymeric blend shape memory polymers (SMPs) can be constructed from two immiscible polymeric matrices. The shape recovery behavior of these composite systems can be easily controlled by varying the ratio of the polymer blends. It has been recently discovered that the functionality of SMPs can be further enhanced with electroactive ability through the use of conductive fillers. However, the fillers may negatively interact with the SMPs and cause a reduction in the elongation at failure thereby diminishing the shape recovery performance. It is proposed that a plasticizer can be utilized to alter the microstructure of the SMPs with conductive fillers. In this study, a new hybrid SMP is developed by combining single-walled carbon nanotubes (SWCNT) into a poly(lactic acid) (PLA) and thermoplastic polyurethane (TPU) SMP system containing poly(ethylene glycol) (PEG) plasticizer. The incorporation of PEG is able to lower the activation temperature, while enhancing dispersion of SWCNT. The presence of SWCNT can stabilize the SMP system and significantly enhance the shape-fixing capability after deformation at room temperature conditions. By carefully controlling the formulation, an electroactive SMP can be created by optimizing the amount of SWCNT and PEG plasticizer.
Making Dressing Easier: Smart Clothes to Help With Putting Clothes on Correctly
(IEEE, 2019) Chu, Marco; Sun, Yu-Chen; Ashraf, Asad; Alves, Silas F. R.; Nejat, Goldie; Naguib, Hani E.
Dressing is an Activity of Daily Living (ADL) that can be difficult to do for individuals living with cognitive disorders and can, therefore, negatively impact their quality of life. Our research focuses on the development of an assistive robot and smart clothing system to aid a user with this ADL. In this paper, we present our autonomous Clothing Perception System that uniquely incorporates smart sensors into clothing in order to perceive if a person has worn the clothes correctly. Four different dressing states can be identified: correctly worn; partially worn; backwards; or inverted (inside out). Our novel system uses a combination of capacitive sensors, contact switches, an infrared LED and an RGB-D sensor to determine the dressing state. The multi-modal sensing system was integrated into a collared shirt and tested to verify its performance. Results with different individuals putting on the shirt showed that the system was able to perceive the four distinct dressing states for all of them.
Polyurethane aerogel-based triboelectric nanogenerator for high performance energy harvesting and biomechanical sensing
(Elsevier, 2019) Saadatnia, Zia; Mosanenzadeh, Shahriar Ghaffari; Li, Terek; Esmailzadeh, Ebrahim; Naguib, Hani E.
This work presents a high performance triboelectric nanogenerator (TENG) based on nanoscale porous polyurethane aerogel (PUA) for effective mechanical energy harvesting and biomechanical sensing. Through a controlled process, flexible thin films of PUA are fabricated and corresponding physical and chemical properties are characterized to be embedded into the TENG device. The electrical output characteristics of the PUA-TENG is investigated using the aerogel films with different porosity levels ranging from 0 to 94% open-cell content. The PUA-TENG with 33% open-cell content shows the highest performance where the open-circuit voltage and short circuit current are 3.5-times higher than those of the TENG with non-porous film. The improvement is due to the enhanced capacitive and surface properties of the applied polymeric aerogel film. The PUA-TENG is capable of charging different capacitors for energy harvesting applications under mechanical agitation. The device can be mounted on a human arm for monitoring the arm motion as a biomechanical sensor. Therefore, the PUA-TENG demonstrates to work effectively for both energy harvesting and biomechanical sensing.
4D-printed hybrids with localized shape memory behaviour: Implementation in a functionally graded structure
(Nature Research, 2019-12-10) Sun, Yu-Chen; Wan, Yimei; Nam, Ryan; Chu, Marco; Naguib, Hani E
4D-printed materials are an emerging field of research because the physical structure of these novel materials respond to environmental changes. 3D printing techniques have been employed to print a base material with shape memory properties. Geometrical deformations can be observed once an external stimulus triggers the shape memory effect (SME) integrated into the material. The plasticizing effect is a well-known phenomenon where the microscopic polymer chain movements have been altered and reflected in different shape memory behaviour. It has been suggested that a 4D material with localized actuation behaviour can be fabricated by utilizing functionally graded layers made from different degrees of plasticizing. This study demonstrated that a novel 4D material can be fabricated from material extraction continuous printing technique with different loadings of poly(ethylene glycol) (PEG) plasticize, achieving localized thermal recovery. The results indicate that a plasticized functional layer is an effective technique for creating next generation 4D materials.
Scalable sensing of hydrocarbon pollutants using soluble chemiresistive polymer composites
(2020) Seshadri, Akshay; Vedula, Ganesh; Naguib, Hani E.
Hydrocarbon leakages are incredibly prominent in today's oil and gas transportation infrastructure, causing several billion dollars of environmental damage annually. Mitigation of this issue is primarily carried out via leak detection sensor systems using fiber optics cables, which are highly prone to failure but are conventionally utilized in industry due to a lack of commercially feasible alternatives. Likewise, sensor solutions in literature have also proven infeasible, featuring high accuracies coupled with difficulties in technology scale-up. Herein we develop a unique hydrocarbon sensor with both scalability and accuracy, using hydrocarbon-soluble polymers in composite chemiresistive sensors. The design's novelty is based on the simple yet highly potent effects of dissolution that take place after exposure to aromatic elements of hydrocarbons pollutants. Large structural deformations are caused in the sensor and can be detected quickly and accurately. In this study, four soluble polymers are characterized for hydrocarbon susceptibility via crude oil exposure, and show large changes in physical and rheological properties. Large electrical sensor response magnitudes are achieved, of up to 180% in 1 h and 27555% in 6 h. Overall, high efficacy in hydrocarbon leak detection is achieved, validating the sensing effectiveness of this unique, hydrocarbon-soluble polymer-based design.
Polyimide aerogels with novel bimodal micro and nano porous structure assembly for airborne nano filtering applications
(2020) Mosanenzadeh, Shahriar Ghaffari; Saadatnia, Zia; Karamikamkar, Solmaz; Park, Chul B.; Naguib, Hani E.
Aerogels have presented a very high potential to be utilized as airborne nanoparticles' filtration media due to their nanoscale pore size and extremely high porosity. The filtering performance of aerogels, such as air permeability and filtration efficiency, is highly related to the configuration of aerogels' nanostructure assembly. However, as aerogel morphology is formed with respect to the intermolecular forces during the gelation stage, tailoring the aerogel nanostructure assembly is still a challenge. In this work, a novel strategy for tailoring polyimide aerogel nanostructure assembly is proposed by controlled disturbing of the intermolecular forces. From the results, the nanostructure assembly of the 4,4′-oxydianiline (ODA)–biphenyl-tetracarboxylic acid dianhydride (BPDA) polyimide aerogel is tailored to a uniform bimodal micro and nano porous structure. This was achieved by introducing the proper fraction of thermoplastic polyurethane (TPU) chains to the polyimide chains in the solution state and through a controlled process. The fabricated polyimide/TPU aerogels with bimodal morphology presented enhanced filtration performance, with 30% improved air permeability and reduced cell size of 3.51 nm over the conventional ODA–BPDA polyimide aerogels. Moreover, the fabricated bimodal aerogels present the reduced shrinkage, density, and effective thermal conductivity of 6.3% and 0.063 g cm−3, 28.7 mW m−1 K−1, respectively. Furthermore, the bimodal polyimide/TPU aerogels show the higher porosity of 96.5 vol% along with increased mechanical flexibility over the conventional polyimide aerogel with comparable backbone chemistry.
Template-Assisted Self-Assembly of Conductive Polymer Electrodes for Ionic Electroactive Polymers
(Frontiers, 2020) Jo, Andrew; Huet, Clémence; Naguib, Hani E
Ionic electroactive polymers (ionic EAPs) can greatly aid in biomedical applications where micro-sized actuators are required for delicate procedures. Since these types of actuators generally require platinum or gold metallic electrodes, they tend to be expensive and susceptible to delamination. Previous research has solved this problem by replacing the metallic electrodes with conductive polymers (CP) and forming an interpenetrating polymer network (IPN) between the conductive polymer (CP) and the solid polymer electrolyte (SPE). Since these actuators contain toxic ionic liquids, they are unsuitable for biological applications. In this study, we present a novel and facile method of fabricating a biocompatible and ionic liquid-free actuator that uses semi-IPN to hold the CP and Nafion-based SPE layers together. Surface activated fabrication treatment (SAFT) is applied to the precursor-Nafion membrane in order to convert the sulfonyl fluoride groups on the surface to sulfonate. Through template-assisted self-assembly, the CP electrodes from either polyaniline (PANI) or poly(3,4-ethylenedioxythiophene) (PEDOT) interlock with the surface treated precursor-Nafion membrane so that no delamination can occur. The electrodes growth pattern, interfacial layer's thickness, and shape can be controlled by adjusting the SAFT concentration and duration.
Novel origami-inspired metamaterials: Design, mechanical testing and finite element modelling
(2020) Wickeler, Anastasia L.; Naguib, Hani E.
Two novel, origami-inspired, metamaterials were designed, mechanically tested, and modelled. One novel origami model was folded using a triangular based crease pattern and the other was folded using a rectangular based crease pattern. The origami-inspired metamaterial sheets were fabricated from polylactic acid using fused deposition additive manufacturing. Several configurations, parameterized by varying the fold angle, were mechanically tested under compression and impact loads. It was found that the specific elastic compression modulus of these novel designs was higher, ranging from 594 MPa/kg to 926 MPa/kg, than existing origami-inspired structures made based on the popular Ron-Resch design, which had specific elastic compression moduli between 15 MPa/kg to 365 MPa/kg. A finite element model further analysed the stress distribution of the core structures under compression loads. The impact testing results showed that the pattern of the tessellated cores affected the amount of impact force transferred through the samples, whereas the fold angle of the origami-inspired design had little impact on the results. The rectangular structure was shown to transfer approximately 50–75% of the force transferred by the triangular structure under impact loads.

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