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Showing 1 to 20 of 29 for “"spiropyran"”.
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Amino acid interactions of spiropyran
… out to explore the interactions between the spiropyran molecule in its merocyanine zwitterionic merocyanine 'open' form and amino acids. The principal amino acids chosen for investigation were β-Alanine, L-Phenylalanine and 8-Aminocaprylic acid. Both single phase and two-phase switching …
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Controlling and Exploiting Spiropyran-based Mechanochromism
… we report the effect of substituents on spiropyran derivatives substituted</p><p>with H, Br, or NO2 para to the breaking spirocyclic C− O bond using single molecule</p><p>force spectroscopy. The force required to achieve the rate constants of ~ 10 s−1 necessary</p><p>to observe …
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Development of new adaptive materials based on spiropyran molecular photoswitches
Spiropyrans are a family of photochromic compounds that can be reversibly switched between two states: a colourless, non-polar, uncharged spiro form (SP) and a highly coloured, polar, conjugated, zwitterionic merocyanine form (MC), i.e. SP → MC (UV light), MC → SP (green, white light). Furthermore, …
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Investigation of spiropyrans and merocyanines in mixed thin films with long chain alkyl silanes: Towards a command surface for liquid crystal realignment
Spiropyran derivatives containing a variable-length linking chain and either tri- or mono-alkoxy silane end groups were synthesized. Glass slides were deposited with mixed thin films of the spiropyran compounds and either octadecyltrimethoxysilane or octadecyldimethylmethoxysilane. The …
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Multiscale characterization of mechanochemical reactions in mechanophore-crosslinked polymers under shear loading
… provided by a color- and fluorescence-generating spiropyran mechanophore. The opening of spiropyran (SP) into merocyanine (MC) is driven by mechanical force, UV light, or heat, and is reversible. The focus of this dissertation is to evaluate the transformation of SP to MC under shear loading …
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Electrospinning applications in mechanochemistry and multi-functional hydrogel materials
… 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 materials. In addition to color change, the activation of nonpolar spiropyran also results in the …
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Self-healing and ionic interactions: a look into thermal properties of sequence-specific ionic networks and the synthesis of spiropyran monomers for triggerd ionic networks
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2016-11-09 without embargo terms
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Sensing in biological systems
… for reversible analyte binding. The photochromic spiropyran molecule is of particular interest in our research group, as the core structure can be readily functionalised for analyte selectivity, surface attachment, and tuning of the photochromic properties. Photo-controlled switching between the …
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Polymer architecture effects on mechanochemical reactions
… parameters on mechanophore activation using spiropyran mechanophores as a model. The effects of flow rate and sonication intensity are provided. Furthermore, we isolated the effects of molecular mass and chain length pertaining to polymer architecture by synthesizing a series of polymers …
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Preparation and characterization of photo-, thermo-, and solvatochromic materials containing benzospiropyran
… photo-, thermo- and solvatochromic behavior of spiropyran derivatives in various media were investigated by spectroscopic methods in this thesis. It was found that the molecular environment controlled the BSP-MC equilibrium, solvatochromic shift and specific interactions with itself …
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Insights for designing mechanochromic spiropyrans from first principles dynamics and minimum energy pathways
… to investigate the mechanochemical activity of a spiropyran molecule. When a particular bond is broken, the spiropyran changes color. In combination with an understanding of the specific reaction products enhanced by applied forces, this can be exploited to create a mechano-chromophore, which …
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Fracture-induced mechanophore activation and solvent healing in poly(methyl methacrylate)
… through tensile, compressive and shear tests. Spiropyran (SP) has been the chosen mechanophore and this molecule undergoes a ring opening reaction (activation) upon the application of mechanical stress. This activation is accompanied by a change in color and fluorescence as the colorless SP is …
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Physicochemical Study of Nano-structuring Within Ionic Liquids Using Photoswitchable Spirocyclic Compounds
… choice of probe molecule by establishing whether spiropyran (BSP) or spirooxazine (SO) met the required sensitivity to effectively probe the ionic liquids. xiii Subsequent studies (Chapter 3-4) focus upon the effects of nano-structuring in imidazolium and phosphonium based ionic liquids through …
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Stimuli-responsive self-assembling materials comprising amphiphilic copolymers for localized remotely triggered therapeutic delivery
… of 2-(dimethylamino)ethyl methacrylate with a spiropyran methacrylate by atom transfer radical polymerization for increased kinetic control. From there, we optimized the composition of this multiresponsive copolymer such that isomerization of the spiropyran moiety brought about a solubility …
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Molecular tailoring of interfaces for thin film on substrate systems
… (ca. 10^7-10^8 s^-1). The polymer system, spiropyran (SP)- linked polystyrene (PS), undergoes a force-induced chemical reaction causing fluorescence and color change. Activation of SP is evident via a fluorescence signal in thin films subject to high strain-rates. In contrast, quasi-static …
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Photochemical Applications to the Study of Complexity Phospholipid Bilayer Environments
… bilayers, were investigated using novel spiropyran/merocyanine molecular probes. The femtosecond to second dynamics of this system's photochemistry enabled bilayer viscosity and free volume to be studied over a broad time scale. Spiropyrans/merocyanines with different polarity were …
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Mechanophore-Linked Polymers for Studying Mechanochemical Response
… utility of this method was demonstrated with a spiropyran (SP) mechanophore that was found to undergo a mechanically induced 6pi-relectrocyclic ring opening. The mechanokinetics of the SP ring opening were probed and the reaction rate was found to increase linearly with increasing molecular …
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Towards reversible mechanochemically triggered strengthening, toughening and assembly of soft materials
… thus limiting their function to a one time use. Spiropyran (SP) is a unique mechanophore that reversibly switches from a ring-closed state to a ring-open state, merocyanine (MC), in response to a variety of stimuli, including UV light, heat, and mechanical force. Herein, a strategy is proposed to …
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Mechanochromism and Strain-Induced Crystallization in 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 that the SP behaves as a reporter of the mechanical state of the nascent polymer. Uniaxial tensile tests reveal correlations …
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Mechanical and optical characterization of force induced chemical reactions in solid state linear polymers
… mechanophore is studied. The mechanophore, spiropyran (SP), reacts to a merocyanine (MC) form under tensile force when linked into a polymer backbone. This reaction is reversible and can be driven toward either SP or MC photochemically. Reaction of SP to MC (activation) is accompanied by the …
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