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- Creators: Rege, Kaushal
Description
New forms of carbon are being discovered at a rapid rate and prove to be on the frontier of cutting edge technology. Carbon possesses three energetically competitive forms of orbital hybridization, leading to exceptional blends of properties unseen in other materials. Fascinating properties found among carbon allotropes, such as, fullerenes, carbon nanotubes, and graphene have led to new and exciting advancement, with recent applications in defense, energy storage, construction, and electronics. Various combinations of extreme strength, high electrical and thermal conductivity, flexibility, and light weight have led to new durable and flexible display screens, optoelectronics, quantum computing, and strength enhancer coating. The quest for new carbon allotropes and future application persists.
Despite the advances in carbon-based technology, researchers have been limited to sp3 and sp2 hybridizations. While sp3 and sp2 hybridizations of carbon are well established and understood, the simplest sp1 hybridized carbon allotrope, carbyne, has been impossible to synthesize and remains elusive. This dissertation presents recent results in characterizing a new sp1 carbon material produced from using pulsed laser ablation in liquid (PLAL) to ablate a gold surface that is immersed in a carbon rich liquid. The PLAL technique provides access to extremely non-thermal environmental conditions where unexplored chemical reactions occur and can be explored to access the production of new materials. A combination of experimental and theoretical results suggests gold clusters can act as stabilizing agents as they react and adsorb onto the surface of one dimensional carbon chains to form a new class of materials termed “pseudocarbynes”. Data from several characterization techniques, including Raman spectroscopy, UV/VIS spectroscopy, and transmission electron microscopy (TEM), provide evidence for the existence of pseudocarbyne. This completely new material may possess outstanding properties, a trend seen among carbon allotropes, that can further scientific advancements.
Despite the advances in carbon-based technology, researchers have been limited to sp3 and sp2 hybridizations. While sp3 and sp2 hybridizations of carbon are well established and understood, the simplest sp1 hybridized carbon allotrope, carbyne, has been impossible to synthesize and remains elusive. This dissertation presents recent results in characterizing a new sp1 carbon material produced from using pulsed laser ablation in liquid (PLAL) to ablate a gold surface that is immersed in a carbon rich liquid. The PLAL technique provides access to extremely non-thermal environmental conditions where unexplored chemical reactions occur and can be explored to access the production of new materials. A combination of experimental and theoretical results suggests gold clusters can act as stabilizing agents as they react and adsorb onto the surface of one dimensional carbon chains to form a new class of materials termed “pseudocarbynes”. Data from several characterization techniques, including Raman spectroscopy, UV/VIS spectroscopy, and transmission electron microscopy (TEM), provide evidence for the existence of pseudocarbyne. This completely new material may possess outstanding properties, a trend seen among carbon allotropes, that can further scientific advancements.
ContributorsFujikado, Nancy (Author) / Sayres, Scott G (Thesis advisor) / Rege, Kaushal (Thesis advisor) / Green, Matthew D (Committee member) / Arizona State University (Publisher)
Created2018
Description
Current wound closure technology is limited, and lacks key elements \u2014 such as the formation of an immediate seal \u2014 that could otherwise resolve some of the common and life threatening complications associated with certain surgeries. Previous research has produced nanosealants capable of providing that immediate seal through the use of laser activation with a near infrared laser. Here, we have developed a biocompatible suture utilizes the same mechanics to provide the tensile strength needed to replace or supplement existing suture lines. Laser activated tissue integrating sutures (LATIS), are shown to have 75% of the tensile strength of commercially available PGA sutures, while still exhibiting the same laser mediated localized heating effect at power densities of as low as 1.6 W/cm2. LATIS has been shown to reach the temperature ranges needed for protein interdigitation, but suffers from low wet mechanical strength. Preparatory steps or solvents for chemical crosslinking generally dehydrate LATIS sutures, causing a shriveling effect that weakens the overall mechanical strength of the suture. To resolve this, a new method of drying, by which LATIS sutures are dried under tension on a suspended platform, has been shown to decrease control suture strength, but restore the strength of chemically treated LATIS sutures to the level of control sutures or above. These promising results suggest that follow-up work with chemical cross-linkers may produce the increases in LATIS wet strength that are needed for its implementation in deeper tissue surgeries.
ContributorsChang, Andy (Author) / Rege, Kaushal (Thesis director) / Goklany, Sheba (Committee member) / School of Molecular Sciences (Contributor) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05