Mechanochromism of polyurethane based on folding–unfolding of cyano-substituted oligo(p-phenylene) vinylene dimer

Abstract

The incorporation of mechanophores, motifs that transform mechanical stimulus into chemical reaction or optical variation, allows creating materials with stress-responsive properties. The most widely used mechanophore generally features a weak bond, but its cleavage is typical an irreversible process. Here, we showed that this problem can be solved by folding–unfolding of a molecular tweezer. We systematically studied the mechanochromic properties of polyurethanes with cyano-substituted oligo(p-phenylene) vinylene (COP) tweezer (DPU). As a control experiment, a class of polyurethanes containing only a single COP moiety (MPU) was also prepared. The DPU showed prominent mechanochromic properties, due to the intramolecular folding–unfolding of COP tweezer under mechanical stimulus. The process was efficient, reversible and optical detectable. However, due to the disability to form either intramolecular folding or intermolecular aggregation, the MPU sample was mechanical inert.

Graphical abstract

Keywords

mechanochromism / molecular tweezer / folding–unfolding / cyano-substituted oligo( p-phenylene) vinylene / polyurethane

References

[1] Hu H, Ma Z Y, Jia X R . Reaction cascades in polymer mechanochemistry.Materials Chemistry Frontiers, 2020, 4(11): 3115–3129

[2] Deneke N, Rencheck M L, Davis C S . An engineer’s introduction to mechanophores.Soft Matter, 2020, 16(27): 6230–6252

[3] Ciardelli F, Ruggeri G, Pucci A . Dye-containing polymers: methods for preparation of mechanochromic materials.Chemical Society Reviews, 2013, 42(3): 857–870

[4] Wiggins K M, Brantley J N, Bielawski C W . Methods for activating and characterizing mechanically responsive polymers.Chemical Society Reviews, 2013, 42(17): 7130–7147

[5] Li J, Nagamani C, Moore J S . Polymer mechanochemistry: from destructive to productive.Accounts of Chemical Research, 2015, 48(8): 2181–2190

[6] Zeng H, Leng J S, Gu J P, . A thermoviscoelastic model incorporated with uncoupled structural and stress relaxation mechanisms for amorphous shape memory polymers.Mechanics of Materials, 2018, 124: 18–25

[7] Zeng H, Leng J S, Gu J P, . Modeling the strain rate-, hold time-, and temperature-dependent cyclic behaviors of amorphous shape memory polymers.Smart Materials and Structures, 2018, 27(7): 075050

[8] Gu J P, Sun H Y, Fang C Q . A finite deformation constitutive model for thermally activated amorphous shape memory polymers.Journal of Intelligent Material Systems and Structures, 2015, 26(12): 1530–1538

[9] Cai H, Li X, Yin K, . A comparative study on the degradation properties of Mg wire/poly(lactic acid) composite rods: influence of rod diameter.Journal of Materials Engineering and Performance, 2022, 31(11): 9019–9028

[10] Karman M, Verde-Sesto E, Weder C . Mechanochemical activation of polymer-embedded photoluminescent benzoxazole moieties.ACS Macro Letters, 2018, 7(8): 1028–1033

[11] McFadden M E, Robb M J . Force-dependent multicolor mechanochromism from a single mechanophore.Journal of the American Chemical Society, 2019, 141(29): 11388–11392

[12] Chen H, Yang F Y, Chen Q, . A novel design of multi-mechanoresponsive and mechanically strong hydrogels.Advanced Materials, 2017, 29(21): 1606900

[13] Jia Y, Wang S, Wang W J, . Design and synthesis of a well-controlled mechanoluminescent polymer system based on fluorescence resonance energy transfer with spiropyran as a force-activated acceptor and nitrobenzoxadiazole as a fluorescent donor.Macromolecules, 2019, 52(20): 7920–7928

[14] Lin Y J, Barbee M H, Chang C C, . Regiochemical effects on mechanophore activation in bulk materials.Journal of the American Chemical Society, 2018, 140(46): 15969–15975

[15] Sulkanen A R, Sung J, Robb M J, . Spatially selective and density-controlled activation of interfacial mechanophores.Journal of the American Chemical Society, 2019, 141(9): 4080–4085

[16] Wang T S, Zhang N, Dai J W, . Novel reversible mechanochromic elastomer with high sensitivity: bond scission and bending-induced multicolor switching.ACS Applied Materials & Interfaces, 2017, 9(13): 11874–11881

[17] Wang T S, Wang H X, Shen L, . Force-induced strengthening of a mechanochromic polymer based on a naphthalene-fused cyclobutane mechanophore.Chemical Communications, 2021, 57(94): 12675–12678

[18] Cawley P . Structural health monitoring: closing the gap between research and industrial deployment.Structural Health Monitoring, 2018, 17(5): 1225–1244

[19] Raisch M, Genovese D, Zaccheroni N, . Highly sensitive, anisotropic, and reversible stress/strain sensors from mechanochromic nanofiber composites.Advanced Materials, 2018, 30(39): 1802813

[20] Karman M, Verde-Sesto E, Weder C, . Mechanochemical fluorescence switching in polymers containing dithiomaleimide moieties.ACS Macro Letters, 2018, 7(9): 1099–1104

[21] Willis-Fox N, Rognin E, Aljohani T A, . Polymer mechanochemistry: manufacturing is now a force to be reckoned with.Chem, 2018, 4(11): 2499–2537

[22] Vidavsky Y, Yang S J, Abel B A, . Enabling room-temperature mechanochromic activation in a glassy polymer: synthesis and characterization of spiropyran polycarbonate.Journal of the American Chemical Society, 2019, 141(25): 10060–10067

[23] Kabb C P, Obryan C S, Morley C D, . Anthracene-based mechanophores for compression-activated fluorescence in polymeric networks.Chemical Science, 2019, 10(33): 7702–7708

[24] Magrini T, Kiebala D, Grimm D, . Tough bioinspired composites that self-report damage.ACS Applied Materials & Interfaces, 2021, 13(23): 27481–27490

[25] Kim T A, Lamuta C, Kim H, . Interfacial force-focusing effect in mechanophore-linked nanocomposites.Advancement of Science, 2020, 7: 1903464

[26] Seshimo K, Sakai H, Watabe T, . Segmented polyurethane elastomers with mechanochromic and self-strengthening functions.Angewandte Chemie, 2021, 133(15): 8487–8490

[27] Pan Y F, Zhang H, Xu P X, . A mechanochemical reaction cascade for controlling load-strengthening of a mechanochromic polymer.Angewandte Chemie International Edition, 2020, 59(49): 21980–21985

[28] Rohde R C, Basu A, Okello L B, . Mechanochromic composite elastomers for additive manufacturing and low strain mechanophore activation.Polymer Chemistry, 2019, 10(44): 5985–5991

[29] Wu M J, Guo Z, He W Y, . Empowering self-reporting polymer blends with orthogonal optical properties responsive in a broader force range.Chemical Science, 2021, 12(4): 1245–1250

[30] Chen Y J, Yeh C J, Guo Q, . Fast reversible isomerization of merocyanine as a tool to quantify stress history in elastomers.Chemical Science, 2021, 12(5): 1693–1701

[31] Yang J H, Horst M, Werby S H, . Bicyclohexene-peri-naphthalenes: scalable synthesis, diverse functionalization, efficient polymerization, and facile mechanoactivation of their polymers.Journal of the American Chemical Society, 2020, 142(34): 14619–14626

[32] Imato K, Yamanaka R, Nakajima H, . Fluorescent supramolecular mechanophores based on charge-transfer interactions.Chemical Communications, 2020, 56(57): 7937–7940

[33] Zhang Y X, Ren B P, Yang F Y, . Micellar-incorporated hydrogels with highly tough, mechanoresponsive, and self-recovery properties for strain-induced color sensors.Journal of Materials Chemistry C: Materials for Optical and Electronic Devices, 2018, 6(43): 11536–11551

[34] Versaw B A, Mcfadden M E, Husic C C, . Designing naphthopyran mechanophores with tunable mechanochromic behavior.Chemical Science, 2020, 11(17): 4525–4530

[35] Kim T A, Robb M J, Moore J S, . Mechanical reactivity of two different spiropyran mechanophores in polydimethylsiloxane.Macromolecules, 2018, 51(22): 9177–9183

[36] Qiu W L, Gurr P A, Qiao G G . Regulating color activation energy of mechanophore-linked multinetwork elastomers.Macromolecules, 2020, 53(10): 4090–4098

[37] Lee J P, Hwang H, Chae S, . A reversibly mechanochromic conjugated polymer.Chemical Communications, 2019, 55(63): 9395–9398

[38] Calvino C, Guha A, Weder C, . Self-calibrating mechanochromic fluorescent polymers based on encapsulated excimer-forming dyes.Advanced Materials, 2018, 30(19): 1704603

[39] Calvino C, Sagara Y, Buclin V, . Mechanoresponsive, luminescent polymer blends based on an excimer-forming telechelic macromolecule.Macromolecular Rapid Communications, 2019, 40(1): 1800705

[40] Pucci A, Di Cuia F, Signori F, . Bis(benzoxazolyl)stilbene excimers as temperature and deformation sensors for biodegradable poly(1,4-butylene succinate) films.Journal of Materials Chemistry, 2007, 17(8): 783–790

[41] Crenshaw B R, Weder C . Self-assessing photoluminescent polyurethanes.Macromolecules, 2006, 39(26): 9581–9589

[42] Sagara Y, Karman M, Verde-Sesto E, . Rotaxanes as mechanochromic fluorescent force transducers in polymers.Journal of the American Chemical Society, 2018, 140(5): 1584–1587

[43] Sagara Y, Karman M, Seki A, . Rotaxane-based mechanophores enable polymers with mechanically switchable white photoluminescence.ACS Central Science, 2019, 5(5): 874–881

[44] Muramatsu T, Sagara Y, Traeger H, . Mechanoresponsive behavior of a polymer-embedded red-light emitting rotaxane mechanophore.ACS Applied Materials & Interfaces, 2019, 11(27): 24571–24576

[45] Sagara Y, Traeger H, Li J, . Mechanically responsive luminescent polymers based on supramolecular cyclophane mechanophores.Journal of the American Chemical Society, 2021, 143(14): 5519–5525

[46] Chen J, Ziegler A W, Zhao B M, . Chemomechanical-force-induced folding–unfolding directly controls distinct fluorescence dual-color switching.Chemical Communications, 2017, 53(36): 4993–4996

[47] Traeger H, Sagara Y, Kiebala D J, . Folded perylene diimide loops as mechanoresponsive motifs.Angewandte Chemie International Edition, 2021, 60(29): 16191–16199

RIGHTS & PERMISSIONS

Higher Education Press