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Grady ME, Birrenkott CM, May PA, White SR, Moore JS, Sottos NR. Localization of Spiropyran Activation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5847-5854. [PMID: 32396732 DOI: 10.1021/acs.langmuir.0c00568] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Functionalization of planar and curved glass surfaces with spiropyran (SP) molecules and localized UV-induced activation of the mechanophore are demonstrated. Fluorescence spectra of UV-irradiated SP-functionalized surfaces reveal that increases in surface roughness or curvature produce more efficient conversion of the mechanophore to the open merocyanine (MC) form. Further, force-induced activation of the mechanophore is achieved at curved glass-polymer interfaces and not planar interfaces. Minimal fluorescence signal from UV-irradiated SP-functionalized planar glass surfaces precluded mechanical activation testing. Curved glass-polymer interfaces are prepared by SP functionalization of E-glass fibers, which are subsequently embedded in a poly(methyl methacrylate) (PMMA) matrix. Mechanical activation is induced through shear loading by a single fiber microbond testing protocol. In situ detection of SP activation at the interface is monitored by fluorescence spectroscopy. The fluorescence increase during interfacial testing suggests that attachment of the interfacial SP molecule to both fiber surface and polymer matrix is present and able to achieve significant activation of SP at the fiber-polymer matrix interface. Unlike previous studies for bulk polymers, SP activation is detected at relatively low levels of applied shear stress. By linking SP at the glass-polymer interface and transferring load directly to that interface, a more efficient mechanism for eliciting the SP response is achieved.
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Affiliation(s)
- Martha E Grady
- Department of Mechanical Engineering, University of Kentucky, 506 Administration Drive, Lexington, Kentucky 40506, United States
| | - Cassandra M Birrenkott
- Department of Mechanical Engineering, South Dakota School of Mines and Technology, 501 East Saint Joseph Street, Rapid City, South Dakota 57701, United States
| | - Preston A May
- Department of Chemistry, University of Illinois at Urbana-Champaign, 505 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Scott R White
- Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, 104 South Wright Street, Urbana, Illinois 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 North Mathews Avenue, Urbana, Illinois 61801, United States
| | - Jeffrey S Moore
- Department of Chemistry, University of Illinois at Urbana-Champaign, 505 South Mathews Avenue, Urbana, Illinois 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 North Mathews Avenue, Urbana, Illinois 61801, United States
| | - Nancy R Sottos
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, 1304 West Green Street, Urbana, Illinois 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 North Mathews Avenue, Urbana, Illinois 61801, United States
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Vijayamohanan H, Bhide P, Boyd D, Zhou Z, Palermo EF, Ullal CK. Effect of Chemical Microenvironment in Spirothiopyran Monolayer Direct-Write Photoresists. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:3871-3879. [PMID: 30807181 DOI: 10.1021/acs.langmuir.8b03304] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We study the effect of the microenvironment on writing chemical patterns into spirothiopyran monolayers over large areas in a single step with light. Surfaces functionalized with photoresponsive spirothiopyran are fabricated by chemically modifying amine-terminated monolayers. The merocyanine isomer selectively participates in a thiol-Michael addition reaction with maleimide-functionalized molecules, rendering these surfaces ideal for fast, mask-less direct writing. The local microenvironment of spirothiopyran is found to strongly influence the kinetics of photoswitching. The quantum yield of ring opening is found to be 17 times faster for spirothiopyran surrounded by a locally charged environment rich in guanidinium diluent molecules as compared to a closed-packed monolayer without diluents. Hydrophilic environments are also found to improve the kinetics of ring closing. Optimization of the diluent concentration leads to dramatic improvements in both contrast and yield of direct writing. This enables the monolayer to be used for maskless two-color photopatterning in which spatial control over patterning is obtained by varying the relative intensity of incident UV and green light. These experiments demonstrate the capacity of spirothiopyran monolayers to serve as a versatile toolbox for rapid, large-area surface functionalization.
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Affiliation(s)
- Harikrishnan Vijayamohanan
- Department of Materials Science and Engineering , Rensselaer Polytechnic Institute , 110 8th Street , Troy , New York 12180 , United States
| | - Parth Bhide
- Department of Materials Science and Engineering , Rensselaer Polytechnic Institute , 110 8th Street , Troy , New York 12180 , United States
| | - Dante Boyd
- Department of Materials Science and Engineering , Rensselaer Polytechnic Institute , 110 8th Street , Troy , New York 12180 , United States
| | - Zhe Zhou
- Department of Materials Science and Engineering , Rensselaer Polytechnic Institute , 110 8th Street , Troy , New York 12180 , United States
| | - Edmund F Palermo
- Department of Materials Science and Engineering , Rensselaer Polytechnic Institute , 110 8th Street , Troy , New York 12180 , United States
| | - Chaitanya K Ullal
- Department of Materials Science and Engineering , Rensselaer Polytechnic Institute , 110 8th Street , Troy , New York 12180 , United States
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Roldán-Carmona C, Rubia-Payá C, Pérez-Morales M, Martín-Romero MT, Giner-Casares JJ, Camacho L. UV-Vis reflection spectroscopy under variable angle incidence at the air–liquid interface. Phys Chem Chem Phys 2014; 16:4012-22. [DOI: 10.1039/c3cp54658f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Siebenhofer B, Gorelik S, Lear MJ, Song HY, Nowak C, Hobley J. Transient absorption spectroscopy on spiropyran monolayers using nanosecond pump-probe Brewster angle reflectometry. Photochem Photobiol Sci 2013; 12:848-53. [PMID: 23396378 DOI: 10.1039/c3pp25397j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Self-assembled monolayers of 11-(3',3'-dimethyl-6,8-dinitrospiro[chromene-2,2'-indoline]-1'-yl) undecanoic acid (amphiphilic spiropyran) at the air-water interface are studied using Brewster angle reflectometry. Transient kinetics of the spiropyran to merocyanine conversion are recorded in a UV-pump, VIS-probe configuration. By varying the probe wavelength using an optical parametric oscillator, we are able to reconstruct absorption spectra of intermediate states with a time-resolution of 10 nanoseconds, limited by the temporal convolution of the two laser pulses. After UV irradiation, spiropyran converts to merocyanine in two stages. The first occurs within a timescale of several tens of nanoseconds and is heavily convoluted with the system response time, whereas the second stage occurs over a few hundred nanoseconds. During the rise time there is a small red shift in the transient absorption spectrum of ~20 nm. We assign the red shift and the slower kinetics to the isomerization of a merocyanine isomer cis about the central methine bond to those that are trans about the same bond.
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Affiliation(s)
- Bernhard Siebenhofer
- Austrian Institute of Technology GmbH, AIT, BioSensor Technologies, Muthgasse 11, 1190 Vienna, Austria
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Abstract
In the past few years, spiropyran has emerged as the molecule-of-choice for the construction of novel dynamic materials. This unique molecular switch undergoes structural isomerisation in response to a variety of orthogonal stimuli, e.g. light, temperature, metal ions, redox potential, and mechanical stress. Incorporation of this switch onto macromolecular supports or inorganic scaffolds allows for the creation of robust dynamic materials. This review discusses the synthesis, switching conditions, and use of dynamic materials in which spiropyran has been attached to the surfaces of polymers, biomacromolecules, inorganic nanoparticles, as well as solid surfaces. The resulting materials show fascinating properties whereby the state of the switch intimately affects a multitude of useful properties of the support. The utility of the spiropyran switch will undoubtedly endow these materials with far-reaching applications in the near future.
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Affiliation(s)
- Rafal Klajn
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
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Siebenhofer B, Gorelik S, Sadovoy AV, Lear MJ, Song HY, Nowak C, Hobley J. Photoconversion of Spiropyran to Merocyanine in a Monolayer Observed Using Nanosecond Pump-Probe Brewster Angle Reflectometry. Aust J Chem 2012. [DOI: 10.1071/ch12093] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A new apparatus for nanosecond-time-resolved Brewster angle reflectometry is described that can be used to measure transient angle-resolved reflectivity changes in thin films and monolayers in a single pulsed laser shot. In order to achieve this, a cylindrical lens is placed in the probe beam path replacing the goniometer that is usually used for angular scanning in other systems. Using two synchronized nanosecond pulsed lasers in pump-probe configuration it is possible to measure the kinetics of photoinduced conformational changes by altering the delay between pump and probe pulses. The system was used to observe nanosecond time-resolved photodynamics in a spiropyran monolayer at the air-water interface. After UV excitation the spiropyran converted to its merocyanine form in two stages. The first stage occurred with a timescale close to the instrument time resolution (tens of nanoseconds) whereas the second stage occurred over a few hundred nanoseconds.
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