Approaches to polymeric mechanochromic materials

Abstract

Mechanochromic materials respond to mechanical stimuli with a change of their optical properties. Such materials are of interest for many technological applications and support fundamental research as they help improving the understanding of stress transfer in polymeric objects and aid in the identification of the processes that lead to mechanical failure. In this highlight, different approaches are discussed that permit the design of polymeric materials, which signal mechanical stresses through a chromic response. This highlight emphasizes materials that exhibit mechanically induced changes of their intrinsic absorption or emission properties. These responses almost exclusively originate from changes of molecular structure, conformational rearrangements, or disruption of intermolecular interactions. V C 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 640-652

Cyclophane‐Based Fluorescence Tuning Induced by Hydrostatic Pressure Changes

“…Mechanical stimuli can vary photoluminescence properties of organic materials in solution and/or solid states . Mechanoresponsive organic compounds are promising candidates of indicator of applied force, optical data storage and mechano‐bioimaging probes for living cells.…”

“…On the other hand, direct applications of mechanical stimuli to luminescent compounds as solid states have attracted much attention in a decade . Grinding, crushing and tensile deformation significantly affect the photophysical properties of molecular assembled materials .…”

“…A pressure-induced enhancement of the formation of an intramolecular p-stacked conformation is proposed to be responsible.Mechanical stimuli can vary photoluminescence properties of organic materials in solution and/or solid states. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Mechanoresponsive organic compounds are promising candidates of indicator of applied force, optical data storage and mechano-bioimaging probes for living cells. Simple and basic studies on homogeneous solutions of various fluorophores under hydrostatic pressure as one of mechanical forces have been long-term scientific subjects.…”

“…[14,15] Therefore, these facts indicate that pressureinduced fluorescence-tuning, quenching of solutions is an apparently difficult task.On the other hand, direct applications of mechanical stimuli to luminescent compounds as solid states have attracted much attention in a decade. [1][2][3][4][5][6][7][8] Grinding, crushing and tensile deformation significantly affect the photophysical properties of molecular assembled materials. [19][20][21][22][23][24][25][26][27][28] Of several approaches to mechanochromic luminescent materials hitherto examined, cyclic, [29][30][31][32] dendritic, [33][34][35][36][37][38][39][40] and mechanicallyinterlocked [41] compounds, originated from particular structural features, show mechanoresponsive luminescence in the condensed states.…”

Anti‐Stokes‐Belastungsanzeige: Mechanochemische Aktivierung der Triplett‐Triplett‐Annihilierung‐Photonen‐Hochkonversion

“…[1][2][3] Bis heute wurden eine Vielzahl von Mechanochromophoren und Mechanofluorophoren entwickelt, die bei mechanischer Belastung entweder ihre Absorptions-oder Emissionseigenschaften ändern und als empfindliche Kraftsonden im molekularen Maßstab dienen. [4][5][6][7][8] Die kontinuierliche Entwicklung neuer Mechanophore und ihrer jeweiligen Nachweismethoden ist jedoch von grçßter Bedeutung,u md ie kraftinduzierten molekularen Veränderungen und ihren Beitrag zum makroskopischen Versagen des Materials mit der von außen einwirkenden Kraft qualitativ und schließlich auch quantitativ zu korrelieren. Beliebte molekulare Strukturen sind u. a. Spiropyran [9][10][11][12] und seine Rhodamin Derivate, [13][14][15] Diels-Alder-Addukte mit latenten Anthracenen, [16][17][18][19][20][21] persistente delokalisierte Radikale, [22][23][24][25][26] und aggregachrome Farbstoffe.…”