A5023463960- Photopolymerization techniques and applications
- Additive Manufacturing and 3D Printing Technologies
- Polymer composites and self-healing
- Advanced Polymer Synthesis and Characterization
- Dental materials and restorations
- NMR spectroscopy and applications
- Lipid Membrane Structure and Behavior
- Synthesis and properties of polymers
- Photodynamic Therapy Research Studies
- Advanced Materials and Mechanics
- Hydrogels: synthesis, properties, applications
- Advanced Optical Imaging Technologies
- Photonic Crystals and Applications
- Advanced Sensor and Energy Harvesting Materials
- Photorefractive and Nonlinear Optics
- Carbon dioxide utilization in catalysis
- Oxidative Organic Chemistry Reactions
- Advanced MRI Techniques and Applications
University of Colorado Boulder
2018-2021
University of Colorado System
2019
Sandia National Laboratories
2014
Liquid crystalline (LC) elastomers (LCEs) enable large-scale reversible shape changes in polymeric materials; however, they require intensive, irreversible programming approaches order to facilitate controllable actuation. We have implemented photoinduced dynamic covalent chemistry (DCC) that chemically anneals the LCE toward an applied equilibrium only when and where light-activated DCC is on. By using light as stimulus enables programming, bond exchange orthogonal LC phase behavior,...
Semicrystalline polymeric materials possessing extraordinary mechanical properties were rapidly fabricated using light from low viscosity liquids at room temperature.
Photopolymerizable semicrystalline thermoplastics resulting from thiol-ene polymerizations were formed via fast and achieved excellent mechanical properties. These materials have been shown to produce desirable for additive manufacturing (3D printing), especially recyclable printing investment casting. However, while well-resolved prints previously with the thermoplastics, remarkable elongation at break (ϵmax) toughness (T) attained in bulk not realized 3D printed components (ϵmax,bulk ~...
ABSTRACT Different water environments in poly( N ‐isopropyl acrylamide) (PNIPAAm) hydrogels are identified and characterized using 1 H high resolution magic angle spinning (HRMAS) nuclear magnetic resonance (NMR). Local corresponding to a “free” highly mobile species, along with waters showing restricted dynamics resolved these swollen hydro‐gels. For photo‐initiated polymerized PNIPAAm gels, an additional entrapped species is observed. Spin–spin R 2 relaxation experiments support the...
Free-radical polymerizations are used for a wide range of applications but detrimentally impacted by the presence oxygen. Zinc phthalocyanines have been previously as singlet oxygen generators to excite radical-consuming ground-state triplet into its less reactive state prior photoexcitation photoinitiator. We report first time that polymerization can be achieved via irradiation UV band phthalocyanine and photosensitization photoinitiation independently two distinct absorption bands reduce...
Amine–peroxide redox polymerization (APRP) has been highly prevalent in industrial and medical applications since the 1950s, yet initiation mechanism of this radical process is poorly understood so that innovations field are largely empirically driven incremental. Through a combination computational prediction experimental analysis, we elucidate important reaction between amines benzoyl peroxide for ambient production initiating radicals. Our calculations show APRP proceeds through SN2...
Radical photopolymerization (RPP) has grown into a multibillion-dollar technology for reduced energy consumption and waste with increased productivity. However, radical-mediated polymerization ceases almost immediately following discontinuation of irradiation because rapid termination reactive centers. This restricts the wider use RPP in applications that involve light attenuation or irregular surfaces uniform is not guaranteed these challenging exposure conditions resultant undercuring...
We demonstrate that multiple exposures of a two-component holographic photopolymer can quadruple the refractive index contrast material beyond single-exposure saturation limit. Quantitative phase microscopy isolated structures written by laser direct-write lithography is used to characterize process. This technique reveals are made possible diffusion chemical components consumed during writing into previously exposed regions. The ultimate shown be limited solubility fresh multiply region.
Thermoplastics encompass the majority of commercial plastics but are limited to manufacturing techniques that require heat and/or solvent enable material reprocessing and reshaping. Photopolymerization offers a readily accessible in situ alternative conventional processing has typically been restricted cross-linked networks, thus removing potential for recycling/reprocessing materials. In this work, paradigm photopolymerizable thermoplastics consisting semicrystalline thiol–ene polymers with...