Mostafa Bedewy

Mostafa Bedewy
University of Pittsburgh | Pitt · Industrial Engineering

PhD (Michigan); Postdoc (MIT)

About

67
Publications
4,170
Reads
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1,068
Citations
Citations since 2016
37 Research Items
719 Citations
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2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
Introduction
With a background in mechanical design/manufacturing and research experience in synthesis, assembly and characterization of nanostructures, my current research is at the interface between manufacturing and nanoscience.
Additional affiliations
December 2014 - present
Massachusetts Institute of Technology
Position
  • PostDoc Position
December 2013 - present
Massachusetts Institute of Technology
Position
  • PostDoc Position
December 2013 - December 2014
Massachusetts Institute of Technology
Position
  • PostDoc Position
Education
January 2009 - November 2013
University of Michigan
Field of study
  • Mechanical Engineering
October 2006 - November 2008
Cairo University
Field of study
  • Mechanical Design and Production Engineering
September 2001 - July 2006
Cairo University
Field of study
  • Mechanical Design and Production Engineering

Publications

Publications (67)
Conference Paper
While reactor wall preconditioning was previously shown to influence the growth of carbon nanotubes (CNTs) by chemical vapor deposition (CVD), it was previously only limited to studying the accumulating carbon deposits over the history of a large number of growth runs. However, the effect of leaving the reactor walls for an extended period of time...
Article
We present a facile direct-write approach for patterning fluorine-doped nanocarbons directly on molecularly engineered polymers for superhydrophobic and parahydrophobic surfaces. We first synthesized two different polymer films, non-fluorinated and fluorinated polyimides (PIs), by two-step procedure to create poly(amic acid) precursors, followed by...
Article
Origami-based fabrication strategies open the door for developing new manufacturing processes capable of producing complex three-dimensional (3D) geometries from two-dimensional (2D) sheets. Nevertheless, for these methods to translate into scalable manufacturing processes, rapid techniques for creating controlled folds are needed. In this work, we...
Article
The synthesis of vertically aligned carbon nanotubes (CNTs), also referred to as CNT forest, by chemical vapor deposition (CVD) is an intricate process that is sensitive to multiple factors other than control of temperature, pressure, and gas flows. In particular, growth is highly sensitive to factors like ambient humidity, as well as small quantit...
Article
The purpose of this paper is to characterize the dynamics and direction of self-folding of pre-strained polystyrene (PSPS) and non-pre-strained styrene (NPS), which results from local shrinkage using a new process of directed self-folding of polymer sheets based on a resistively heated ribbon that is in contact with the sheets. A temperature gradie...
Chapter
In modern manufacturing, natural materials represent a powerful template for creating multifunctional structures in a sustainable and eco-friendly way. In addition, biological systems that have evolved against harsh environments in nature for a long period sometimes exhibit excellent properties and unique morphologies compared with man-made materia...
Conference Paper
The growth of laser-induced nanocarbons, referred to here are LINC for short, directly on polymeric surfaces is a promising route toward surface engineering of commercial polymers. This paper aims to demonstrate how this new approach can enable achieving varied surface properties based on tuning the nanostructured morphology of the formed graphitic...
Conference Paper
The synthesis of vertically aligned carbon nanotubes (CNTs), also referred to as CNT forest, by chemical vapor deposition (CVD) is an intricate process that is sensitive to multiple factors other than control of temperature, pressure, and gas flows. In particular, growth is highly sensitive to factors like ambient humidity, as well as small quantit...
Conference Paper
Origami-based fabrication strategies open the door for developing new manufacturing processes capable of producing complex three-dimensional (3D) geometries from two-dimensional (2D) sheets. Nevertheless, for these methods to translate into scalable manufacturing processes, rapid techniques for creating controlled folds are needed. In this work, we...
Article
The growth of laser-induced nanocarbons, referred to here as laser-induced nanocarbon (LINC) for short, directly on polymeric surfaces is a promising route toward surface engineering of commercial polymers. This paper aims to demonstrate how this new approach can enable achieving varied surface properties based on tuning the nanostructured morpholo...
Article
Understanding and controlling the growth of vertically aligned carbon nanotube (VACNT) forests by chemical vapor deposition (CVD) is essential for unlocking their potential as candidate materials for next generation energy and mass transport devices. These advances in CNT manufacturing require developing in situ characterization techniques capable...
Article
In chemical vapor deposition (CVD) of vertically aligned carbon nanotubes (CNTs), temperatures for the following three processes are typically coupled: (1) catalyst nanoparticle formation by film dewetting, (2) thermal decomposition of gas precursors, and (3) nucleation/growth of CNTs. Here, we present an approach for complete decoupling of these p...
Article
For the scalable production of commercial products based on vertically aligned carbon nanotubes (VACNTs), referred to as CNT forests, key manufacturing challenges must be overcome. In this work, we describe some of the main challenges currently facing CNT forest manufacturing, along with how we address these challenges with our custom-built rapid t...
Conference Paper
Regenerated silk fibroin (RSF) is an emerging material derived from natural silk. Thin RSF films are transparent, biocompatible and biodegradable, which makes them suitable for many applications, such as flexible/conformal and transient electronics, bioresorbable devices, bioresists for lithography, and edible food protective coatings. To realize t...
Conference Paper
For the scalable production of commercial products based on vertically aligned carbon nanotubes (VACNTs), referred to as CNT forests, key manufacturing challenges must be overcome. In this work, we describe some of the main challenges currently facing CNT forest manufacturing, along with how we address these challenges with our custom-built rapid t...
Article
The root causes underlying run-to-run variations in the synthesis of vertically aligned carbon nanotubes (VACNTs) by chemical vapor deposition can be attributed to the sensitivity of the process to small uncontrolled/unmeasured quantities of gaseous species in the reactor. Hence, universally applicable processing steps are needed to ensure consiste...
Article
Despite extensive academic and commercial development, a comprehensive understanding of the principles necessary for high-yield production of carbon nanotubes (CNTs) is lacking, whether in oriented films, bulk powders, or other forms. In chemical vapor deposition growth of CNT films on substrates, trace contaminants of carbon, such as deposits on t...
Article
Tunability of the properties of regenerated silk fibroin (RSF) films is required for use as flexible substrates in many applications aimed at exploiting their unique mechanical, optical, and degradation properties, such as bioelectronic and biomedical devices. Here, a new approach for programing these properties is demonstrated based on molecular i...
Conference Paper
Precise and firm fixation of the cranium is critical during craniotomy and delicate brain neurosurgery making head immobilization devices (HIDs) a staple instrument in brain neurosurgical operations today. However, despite their popularity, there is no standard procedure for their use and many complications arise from using HIDs in pediatric neuros...
Conference Paper
The purpose of this paper is to characterize the kinetics and direction of self-folding of pre-strained polystyrene (PSPS) and non-pre-strained styrene (NPS), which results from local shrinkage using a resistively heated ribbon in contact with the polymer sheet. A temperature gradient across the thickness of this shape memory polymer (SMP) sheet in...
Article
Full-text available
Synthetic protein assemblies that adopt programmed shapes would support many applications in nanotechnology. We used a rational design approach that exploits the modularity of orthogonally interacting coiled coils to create a self-assembled protein nanotriangle. Coiled coils have frequently been used to construct nanoassemblies and materials, but r...
Article
Background: Head immobilization devices (HIDs) are a staple of neurosurgical procedures, including in the intraoperative magnetic resonance imaging (iMRI) operating rooms (ORs) where material modifications were necessary for compatibility with the magnets utilized. Objective: To present the experience in this OR environment and discuss the multi...
Article
Full-text available
Aligned carbon nanotubes (CNTs) possess great potential for transforming the fabrication of advanced interfacial materials for energy and mass transport as well as for structural composites. Realizing this potential, however, requires building a deeper understanding and exercising greater control on the atomic scale physicochemical processes underl...
Article
The properties of carbon nanotube (CNT) materials, and many analogous materials comprising filamentary nanostructures, are governed by the intrinsic filament properties and their hierarchical organization and interconnection. As a result, direct knowledge of the collective dynamics of CNT synthesis and self-organization is essential to engineering...
Article
Understanding the collective growth of vertically aligned carbon nanotube (CNT) populations is key to tailoring their properties for many applications. During the initial stages of CNT growth by chemical vapor deposition (CVD), catalyst nanoparticle formation by thin-film dewetting and the subsequent CNT nucleation processes dictate the CNT diamete...
Article
Consistent synthesis of carbon nanotubes (CNTs) using laboratory-scale methods is essential to the development of commercial applications, particularly with respect to the verification of recipes that achieve control of CNT diameter, chirality, alignment, and density. Here, we report that, transients in the moisture level and carbon concentration d...
Article
The outstanding properties of individual carbon nanotubes (CNTs) have motivated interest in CNT fibers for composite materials, high-strength conductors and multifunctional textiles. However, despite advances in manufacturing, the strength of CNT fiber remains 10–100 fold less than individual CNTs. In light of the complex, multi-scale load transfer...
Article
Electrostatic loading is widely used for sensing and actuation in miniaturized electromechanical systems, yet classical designs involve geometric patterning of solid materials such as silicon and metal films. Conductive nanoporous materials for electrostatics may enable engineering of new functionalities arising from their compliance, internal surf...
Article
Full-text available
div class="title">Fast Imaging of Carbon Nanotube Carpet Growth by Environmental TEM - Volume 21 Issue S3 - Dmitri N. Zakharov, Mostafa Bedewy, Viswanath Balakrishnan, Sebastian W. Pattinson, Eric R. Meshot, A.John Hart, Eric A. Stach
Article
Understanding of the electrostatic properties of carbon nanotube (CNT) forests is essential to enable their integration in microelectronic and micromechanical devices. In this study, we sought to understand how the hierarchical geometry and morphology of CNT forests determines their capacitance. First, we find that at small gaps, solid micropillars...
Article
Natural materials such as bone and tooth achieve precisely tuned mechanical and interfacial properties by varying the concentration and orientation of their nanoscale constituents. However, the realization of such control in engineered foams is limited by manufacturing-driven tradeoffs among the size, order, and dispersion uniformity of the buildin...
Article
Full-text available
Objective: Carbon nanotubes (CNTs) are attractive for use in peripheral nerve interfaces because of their unique combination of strength, flexibility, electrical conductivity and nanoscale surface texture. Here we investigated the growth of motor neurons on thin films of horizontally aligned CNTs (HACNTs). Approach: We cultured primary embryonic...
Article
Control of the uniformity of vertically aligned carbon nanotube structures (CNT "forests"), in terms of both geometry and nanoscale morphology (density, diameter and alignment), is crucial for applications. Many studies report complex and sometimes unexplained spatial variations of the height of macroscopic CNT forests, as well as variations among...
Article
Micro-mechanical experiments, image analysis, and theoretical modeling revealed that local failure events and compressive stresses of vertically aligned carbon nanotubes (VACNTs) were uniquely linked to relative density gradients. Edge detection analysis of systematically obtained scanning electron micrographs was used to quantify a microstructural...
Article
The widespread potential application of vertically aligned carbon nanotube (CNT) forests have stimulated recent work on large-area chemical vapor deposition growth methods, but improved control of the catalyst particles is needed to overcome limitations to the monodispersity and packing density of the CNTs. In particular, traditional thin-film depo...
Article
Engineering the density of carbon nanotube (CNT) forest microstructures is vital to applications such as electrical interconnects, micro-contact probes, and thermal interface materials. For CNT forests on centimeter-scale substrates, weight and volume can be used to calculate density. However, this is not suitable for smaller samples, including ind...
Article
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 and commercialization. For example, it is well known that CNT growth can be influenced by small concentrations of water vapor, c...
Article
Aligned carbon nanotube (CNT) structures are promising for many applications; however, as-grown CNT "forests" synthesized by chemical vapor deposition (CVD) are typically low-density and mostly comprise tortuous defective CNTs. Here, we present evidence that the density and alignment of self-organized CNT growth is limited by mechanical coupling am...
Article
Full-text available
Hierarchically ordered carbon nanotubes (CNTs) are promising for integration in high-performance structural composites, electrical interconnects, thermal interfaces, and filtration membranes. These and other applications require CNTs that are monodisperse, well aligned, and densely packed. Moreover, because more than 1 billion CNTs per square centi...
Conference Paper
The family of cylindrical parallel-axis involute gearing currently include spur, helical and double-helical gears, all having straight tooth traces in the developed pitch plane. However, gears with curved tooth traces have also been proposed. One of the obvious merits of this configuration is the insensitivity to shaft misalignment. Although this a...
Article
The production of high-performance carbon nanotube (CNT) materials demands understanding of the growth behavior of individual CNTs as well as collective effects among CNTs. We demonstrate the first use of grazing incidence small-angle X-ray scattering to monitor in real time the synthesis of CNT films by chemical vapor deposition. We use a custom-b...
Article
Hybrid nanostructured materials can exhibit different properties than their constituent components, and can enable decoupled engineering of energy conversion and transport functions. Novel means of building hybrid assemblies of crystalline C 60 and carbon nanotubes (CNTs) are presented, wherein aligned CNT films direct the crystallization and orien...
Article
Full-text available
Capillary forces provide a ubiquitous means of organizing micro- and nanoscale structures on substrates. In order to investigate the mechanism of capillary self-assembly and to fabricate complex ordered structures, precise control of the meniscus shape is needed. We present a precision instrument that enables deposition of liquid droplets spanning...
Article
Export Date: 1 October 2012, Source: Scopus, CODEN: AFMDC, doi: 10.1002/adfm.201102393, Language of Original Document: English, Correspondence Address: Hart, A.J.; Department of Mechanical Engineering, University of Michigan, 2350 Hayward Street, Ann Arbor, MI 48104, United States; email: ajohnh@umich.edu, References: Park, C., Song, H.J., Choi, H....
Article
Understanding the population growth behavior of filamentary nanostructures, such as carbon nanotubes (CNTs), is hampered by the lack of characterization techniques capable of probing statistical variations with high spatial resolution. We present a comprehensive methodology for studying the population growth dynamics of vertically aligned CNT fores...
Article
Full-text available
Owing to their inherent tortuosity, the collective height of vertically aligned nanostructures does not equal the average length of the individual constituent nanostructures, and therefore temporal height measurement is not an accurate measure of the genuine growth kinetics. We use high-resolution spatial mapping of alignment by small-angle X-ray s...
Article
We demonstrate fabrication of multidirectional and hierarchical carbon nanotube (CNT) films on diverse substrates, using nanocomposite catalyst films prepared by layer-by-layer (LBL) assembly. CNT density and yield are controlled by the thickness of a montmorillonite clay/poly(dyallyldimethyl ammonium chloride (MTM/PDDA) support film. Using identic...
Article
Full-text available
While carbon nanotubes (CNTs) have been produced industrially in ton-scale quantities for nearly two decades, scalable manufacturing processes that precisely control the structure, length, and alignment of CNTs are needed to realize the exceptional properties of CNTs at larger scales. Specifically, vertically aligned CNT forests are a model system...
Conference Paper
In the past two decades the wind turbine industry has witnessed a considerable number of catastrophic accidents, many of which were due to gearbox failure. Ever increasing power ratings at decreased rotor speeds result in rotor torques of some million Nm. This imposes tooth loads and planet/pinion bearing loads on the order of a hundred tons within...
Article
This paper focuses on the final reduction stage of heavy-lift rotorcraft transmissions, typically constructed as a double-helical bull gear surrounded by several slender pinions in split-power paths from each engine. These gears are herein suggested to be re-conceived as curved-tooth gears, C-gears for short. An enumeration and a classification of...
Article
We explain the evolution and termination of vertically aligned carbon nanotube (CNT) “forests” by a collective mechanism, which is verified by temporal measurements of forest mass and height, as well as quantitative spatial mapping of CNT alignment by synchrotron X-ray scattering. We propose that forest growth consists of four stages: (I) self-orga...
Article
Understanding the termination event in the growth of carbon nanotubes (CNTs) by chemical vapor deposition (CVD) is a roadblock in the pursuit of ultra-long CNTs, which would be useful for many of applications. Our previous in situ measurements show that vertically-aligned CNT ``forest'' growth terminates abruptly, which is not predicted by widely s...
Article
Owing to the exceptional and anisotropic properties of carbon nanotubes (CNTs), vertically aligned CNT "forests" are a highly attractive thin film material for multifunctional enhancement of composite interfaces. We present two designs for continuous manufacturing of aligned CNT forests, wherein high-quality CNT forests are grown on continuously-fe...

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