A5066158471- Additive Manufacturing and 3D Printing Technologies
- Manufacturing Process and Optimization
- Additive Manufacturing Materials and Processes
- Injection Molding Process and Properties
- 3D Printing in Biomedical Research
- biodegradable polymer synthesis and properties
- Polymer crystallization and properties
- Bone Tissue Engineering Materials
- Advanced Polymer Synthesis and Characterization
- Polymer composites and self-healing
- Block Copolymer Self-Assembly
- Rheology and Fluid Dynamics Studies
- Polymer Nanocomposites and Properties
- Mechanical Behavior of Composites
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Innovative Microfluidic and Catalytic Techniques Innovation
- Particle Accelerators and Free-Electron Lasers
- Photopolymerization techniques and applications
- Metallurgy and Material Forming
- Electrospun Nanofibers in Biomedical Applications
- Flame retardant materials and properties
- Semiconductor Lasers and Optical Devices
- Tissue Engineering and Regenerative Medicine
- Innovations in Concrete and Construction Materials
National Institute of Standards and Technology
2015-2025
Material Measurement Laboratory
2014-2025
National Institute of Standards
2014-2017
University of Delaware
2010-2014
Aalto University
2011
University of Reading
2010
Case Western Reserve University
2010
Outokumpu (Finland)
1998-2004
University of Helsinki
1992
MIT Lincoln Laboratory
1989
An elastomeric, healable, supramolecular polymer blend comprising a chain-folding polyimide and telechelic polyurethane with pyrenyl end groups is compatibilized by aromatic π−π stacking between the π-electron-deficient diimide π-electron-rich units. This interpolymer interaction key to forming tough, elastomeric material. Variable-temperature FTIR analysis of bulk material also conclusively demonstrates presence hydrogen bonding, which complements interactions. SAXS shows that healable...
A combination of thermography, rheology, and fracture mechanics captures weld formation during the material extrusion process.
Embedded 3D printing enables the manufacture of soft, intricate structures. In technique, a nozzle is embedded into viscoelastic support bath and extrudes filaments or droplets. While expands printable materials space to low-viscosity fluids, it also presents new challenges. Filament cross-sections can be tall narrow, have sharp edges, rough surfaces. Filaments rupture contract due capillarity, harming print fidelity. Through digital image analysis in situ videos process images just after...
Abstract The Additive Manufacturing Benchmark Test Series (AM Bench) provides rigorous measurement data for validating additive manufacturing (AM) simulations a broad range of AM technologies and material systems. Bench includes extensive in situ ex measurements, simulation challenges the modeling community, corresponding conference series. In 2022, second round challenge problems, were completed, focusing primarily upon laser powder bed fusion (LPBF) processing metals, both extrusion vat...
Embedded 3D printing, wherein fluid inks are extruded into support baths, has enabled the manufacture of complex, custom structures ranging from cell-laden tissue analogues to soft robots. This method encompasses two techniques: embedded ink writing (EIW), where filaments extruded, and droplet printing (EDP), droplets suspended. Materials for can be Newtonian, but often both bath yield stress fluids, following elastic behavior below shear-thinning, viscous above stress. The effect surface...
A polyacrylamide hydrogel system that can be liquefied by remote activation using UV irradiation is investigated as a degradable adhesive. The linear copolymer, formed conventional free-radical polymerization, contains biomimetic catechol–iron-mediated cross-linkers are sensitive to pH changes. Hydrogel films and bulk gels prepared basic titration of polymer solution doped with photoacid generator, diphenyliodonium chloride, generating an ionic cross-linked network via the catechol pendant...
We present a spatially resolved approach for the solvent vapor annealing (SVA) of block copolymer thin films that permits facile and relatively rapid manipulation nanoscale ordering nanostructure orientation. In our method, localized (point) SVA zone is created through use delivery nozzle. This point can be rastered across film using motorized stage to control local structure orientation in cylinder-forming ABA triblock film. At moderate rastering speeds (∼100 μm/s) (i.e., modest time at...
It is widely known that the printing quality of fused filament fabrication (FFF) heavily affected by environmental temperature and humidity, taking form warping porosity. However, there little understanding about quantitative relations between conditions, geometry, mechanical properties printed parts. In this study, we systematically investigated those using bisphenol A polycarbonate as a model material system. For temperature, an in-situ infrared imaging analysis revealed presence up to 5.4...
Controlling the nanostructure of self-assembled block copolymer thin films is critical for applications in nanotemplate design, nanoporous membranes, and organic optoelectronics. In this study, we employed a gradient approach to examine effects substrate surface chemistry film thickness on self-assembly cylinder-forming poly(styrene-b-isoprene-b-styrene) (SIS) films. Using gradients from 85 120 nm (3.1d 4.4d), found that contained parallel cylinders both bare silicon substrates...
Diels−Alder (DA) chemistry is increasing popular due to its simplicity and efficiency; however, one concept that has yet be thoroughly explored incorporation of DA linkages within materials for the development polymeric phase change materials. It well established retro-DA reaction results in a large endotherm, which could potential energy sink Hydroxyl-terminated polybutadiene (HTPB) was selected as prepolymer modified with different linkages. Cured were prepared upon addition diisocyanates...
A series of thiol-ene generated amphiphilic cross-linked networks was prepared by reaction alkene-modified Boltorn polyesters (Boltorn-ene) with varying weight percent 4-armed poly(ethylene glycol) (PEG) tetrathiol (0–25 wt %) and equivalents pentaerythritol tetrakis(3-mercaptopropionate) (PETMP) (0–64 %). These materials were designed to present complex surface topographies morphologies, heterogeneity composition properties robust mechanical properties, serve as nontoxic antibiofouling...
Polymer nanofiber based materials have been widely investigated for use as tissue engineering scaffolds. While promising, these are typically fabricated through techniques that require significant time or cost. Here we report a rapid and cost effective air-brushing method fabricating scaffolds using simple handheld apparatus, compressed air, polymer solution. Air-brushing also facilities control over the scaffold degradation rate without adversely impacting architecture. This was...
Abstract Biofabrication has been adapted in engineering patient-specific biosynthetic grafts for bone regeneration. Herein, we developed a three-dimensional (3D) high-resolution, room-temperature printing approach to fabricate osteoconductive scaffolds using calcium phosphate cement (CPC). The non-aqueous CPC bioinks were composed of tetracalcium phosphate, dicalcium anhydrous, and Polyvinyl butyral (PVB) dissolved either ethanol (EtOH) or tetrahydrofuran (THF). They printed an aqueous...