Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"Mechanophore"”.
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Mechanophore-Linked Polymers for Studying Mechanochemical Response
… proof-of-concept experiment demonstrated that a mechanophore-linked polymer could be activated site-specifically via ultrasound-induced mechanical forces. Building on this idea, a method was established to synthesize mechanophore-linked poly(methyl acrylate) in an efficient manner using single …
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Mechanophore activation at heterointerface and surface crowdedness as a determining factor
… in polymer mechanochemistry around the topic of mechanophore, a molecular unit that chemically responds in a selective manner to a mechanical perturbation, design and development. Most of the research is focused on mechanophore embedded polymers. However, behavior of mechanophores at …
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Fracture-induced mechanophore activation and solvent healing in poly(methyl methacrylate)
… in engineering materials. The potential of using mechanophores, stress-sensitive molecules, as material stress sensors has been established through tensile, compressive and shear tests. Spiropyran (SP) has been the chosen mechanophore and this molecule undergoes a ring opening reaction …
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Multiscale characterization of mechanochemical reactions in mechanophore-crosslinked polymers under shear loading
… response is achieved through the use of a mechanophore, a single molecule with a detectable, force-driven chemical response, linked to the polymer backbone. In this dissertation, evidence of a mechanically-induced local chemical reaction (an electrocyclic ring-opening) is provided by a …
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Investigating Shear-induced Damage during Hydrogel Extrusion-based Manufacturing: Rheological Insights and Mechanophore Incorporation
… printing conditions. The introduction of mechanophores into hydrogel structures was made to visually monitor and quantify shear-induced damage under different flow conditions. Hydrogels showed mechanochromic behaviour during extrusion due to the activation of spiropyran moieties, where …
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Mechanical and optical characterization of force induced chemical reactions in solid state linear polymers
… By linking force-sensitive chemical species (mechanophores) into polymer backbones, mechanical force can drive chemical reactions. Mechanophores have been developed with potential as damage sensing, self-healing, and self-reinforcing materials. This research investigates the conditions for …
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Mechanochromism and Strain-Induced Crystallization in Thiol-yne-derived Stereoelastomers
… response of SIC, and the molecular response of mechanophore activation. Here we report thiol-yne-derived stereoelastomers, doped covalently with a dipropiolate-derivatized spiropyran (SP) mechanophore. Material properties of SP-containing films are consistent with undoped controls, indicating …
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Mechanochemical activation at solid interfaces
… resulting from activation of force-sensitive mechanophore modified interfaces remains largely unexplored. In this dissertation, two different functionalization approaches to molecularly tailor interfacial changes are investigated. First, the influence of SAM tail group chemistry on the …
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Force-induced mechanochemical reactions in polymeric systems
… presented investigates the spiropyran (SP) mechanophore (force-sensitive molecule) incorporated into different polymer systems. The SP mechanophore converts to a colored and fluorescent merocyanine (MC) form upon the application of heat, UV light, or mechanical force, when linked into a …
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Synthesis and Development of Novel Cyclobutane Mechanophores
… mechanically active chemical moieties known as mechanophores. These mechanophores could then be utilized for localized self-healing or self-repair of polymer composites. To date there have been few attempts at systematically investigating the effects of mechanophore structure upon rates of …
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Design and synthesis of mechanoresponsive materials and multivalent polymer-peptide conjugates
… examples of intrinsic functionalization. First, mechanophores are incorporated into polymers and impart function when materials are subjected to mechanical force. Second, multivalent polymer-peptide conjugates (mPPCs) are synthesized by the post polymerization modification of a polymer backbone …
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Polymer architecture effects on mechanochemical reactions
… to undergo site-specific bond cleavage, termed mechanophores. An overarching theme in polymer mechanochemistry is that the polymer chains are the link between macroscopic energy and the mechanophore. Therefore, polymer architecture is thought to play a significant role in influencing these types …
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Electrospinning applications in mechanochemistry and multi-functional hydrogel materials
… productive when stress-sensitive molecules, or mechanophores, are incorporated into materials. One mechanophore that has been heavily investigated is spiropyran, a molecule that exhibits a color change when activated, although large strains are required to achieve this activation in elastomeric …
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Control of mechanochromic reactions in a polymer matrix
Mechanophores are force sensitive molecules that undergo productive chemical transformations under a mechanical force including color change, small molecule release, and cross-linking. Productive chemical transformations depend on the intrinsic molecular structure as well as the extrinsic …
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Towards reversible mechanochemically triggered strengthening, toughening and assembly of soft materials
… times. With the exception of color switching mechanophores, the majority of mechanochemical reactions developed in the lab are completely irreversible, thus limiting their function to a one time use. Spiropyran (SP) is a unique mechanophore that reversibly switches from a ring-closed state to …
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Spiropyrans as color-generating mechanophores
… bond changes in force-sensitive molecules called mechanophores potentially allows a much wider range of polymer responses to be accessed. In an effort to show the feasibility of this concept, a series of spiropyran-based mechanophores were designed which were expected to undergo a 6-π …
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Controlling and Exploiting Spiropyran-based Mechanochromism
… reactions. These functionalities, known as mechanophores,</p><p>react to unveil a new molecular structure and triggering a constructive response. This</p><p>strategy has been explored for a variety of purposes, including stress sensing, stress</p><p>strengthening, small molecule release, …
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Junctions and Strands: Breaking Property Tradeoffs in Polymer Networks and Composite Polymer Electrolytes
… incorporation of forceresponsive molecules (mechanophores) that may either toughen or weaken the material depending on network construction and topology. The first part of this thesis identifies a new class of mechanophores called tetrafunctional cyclobutanes (TCBs), which can be used to …
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Mechanochemical Reaction Development for Addition, Elimination, and Isomerization
… 2-methoxy-gem-difluorocyclopropane (MeO-gDFC) mechanophores in polymers. Pulsed ultrasonication of a MeO-gDFC containing polymer leads to one equivalent of HF release per MeO-gDFC activation. We further quantify the mechanochemical reactivity of MeO-gDFC by single molecule force spectroscopy, …
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