Strongly size-dependent electronic properties inC60-encapsulated zigzag nanotubes and lower size limit of carbon nanopeapods

Carbon can produce a wide variety of systems and nanostructures with different dimensionality as exemplified by fullerenes, nanotubes and graphene, all with peculiar properties of great interest for fundamental and applied research. In this framework sp-hybridized carbon atoms can arrange to form atomic wires with size dependent functional properties. The sp form of carbon has a long story passing through astrophysics and minerals found in meteor craters and, although still considered elusive and unstable, nowadays a number of nano-systems constituted by or containing sp-carbon wires have been produced and characterized. As graphene is considered the thinnest material (one-atom thick), carbon atomic wires represent true 1-dimensional systems (one- atom diameter) with a great potential for nanoscience and nanotechnology. The status of research on carbon atomic wires is here discussed, starting from the description of ideal systems to real structures, showing that the properties can be tuned by controlling the wire length (i.e. number of carbon atoms) and termination (atom, molecular group or nanostructure). Synthesis techniques are presented as well as strategies to have stable wires. A particular attention will be given to the use of vibrational spectroscopy to provide insight on the structure and electronic properties of these systems. Perspectives for novel devices based on the exploitation of the electronic properties of these systems are also discussed.

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Flow Imaging Microscopy as a Novel Tool for High-Throughput Evaluation of Elastin-like Polymer Coacervates

10.26434/chemrxiv.7367708.v1 ◽

2018 ◽

Author(s):

Laura Marvin ◽

Wynter Paiva ◽

Nicole Gill ◽

Marissa A. Morales ◽

Jeffrey Mark Halpern ◽

...

Keyword(s):

Environmental Remediation ◽

Industrial Applications ◽

Genetically Engineered ◽

Particle Analysis ◽

Synthesis Methods ◽

Flow Imaging ◽

Size Limit ◽

Imaging Results ◽

Polymer Microparticles ◽

Lower Size

<div>Biological and bioinspired polymer microparticles have broad biomedical and industrial applications, including drug delivery, tissue engineering, surface modification, environmental remediation, imaging, and sensing. Full realization of the potential of biopolymer microparticles will require methods for rigorous characterization of particle sizes, morphologies, and dynamics, so that researchers may correlate particle characteristics with synthesis methods and desired functions. Toward this end, we evaluated biopolymer microparticles using flow imaging microscopy. This technology is widely used in the biopharmaceutical industry but is not yet well-known among the materials community. Our polymer, a genetically engineered elastin-like polypeptide (ELP), self-assembles into micron-scale coacervates. We performed flow imaging of ELP coacervates using two different instruments, one with a lower size limit of approximately 2 microns, the other with a lower size limit of approximately 300 nanometers. We validated flow imaging results by comparison with dynamic light scattering and atomic force microscopy analyses. We explored the effects of various solvent conditions on ELP coacervate size, morphology, and behavior, such as the dispersion of single particles versus aggregates. We found that flow imaging is a superior tool for rapid and thorough particle analysis of ELP coacervates in solution. We anticipate that researchers studying many types of microscale protein or polymer assemblies will be interested in flow imaging as a tool for quantitative, solution-based characterization.<br></div>

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