Reversibly Photoswitchable Tristate Fluorescence within a Single Polymeric Nanoparticle

Abstract

optical memories, sensors, bioimaging, white-light generation, and anticounterfeiting. [1][2][3][4][5][6][7][8][9][10][11] A variety of stimuli-responsive multistate fluorescent materials in response to a mixing combination of various stimuli such as light, electricity, temperature, pH, ions, solvent vapor, and grinding/smearing have been investigated recently. [12][13][14][15][16][17][18][19][20][21][22][23][24] Among different stimuli, light shows the advantage of remote and noncontact control, dose-dependent, waste-free, noninvasive, high spatial and temporal resolutions, and thus is frequently employed as the external stimulus. [25][26][27][28][29][30] To build a photoswitching mechanism into the systems, photochromic groups like diarylethene (DTE) or spiropyran (SP) derivatives are normally utilized. [31][32][33][34][35][36][37][38][39][40][41][42][43] These systems are mainly made from one photoresponsive and one or two nonphotoresponsive fluorescent groups and thus show ratiometric color change. In such design, the variation of fluorescence color changes is generally limited due to the spectral crosstalk, which hinders their practical applications. [44][45][46] To address this issue, the concept of photoswitchable multistate fluorescent nanosystems has been proposed recently. [47][48][49][50][51][52][53][54][55][56] These systems combine different diarylethene derivatives and can display distinguishable multiple changes in the emission colors. Despite this progress, the systems currently available still do not meet the criteria required for practical application at the same time, including i) distinct multistate emissions with high contrast and the minimum crosstalk between them, ii) emission intensity and color that can be finely tuned, iii) high brightness, excellent water-dispersibility, photoreversibility and storage stability, and iv) versatility in material synthesis and processing for instantaneous application.Herein, we report a class of novel photoswitchable tristate fluorescent polymeric nanoparticles (TS-PFPNs) by covalently incorporating a well-designed photoswitchable fluorescent dyad and two additional photochromic acceptors into a single polymeric nanoparticle. Scheme 1 shows our design. The perylenediimide-spiropyran conjugate (PDI-SP) was selected as the photoswitchable dyad while spiropyran-linked methacrylate (SPMA) and diarylethene derivative (DTEo-1) were employed as the additional acceptors for obtaining ultrahigh-contrast states between three fluorescence states. Without any fluorescenceresonance energy transfer (FRET), the system is expected to show green emission of PDI. When the SP unit of PDI-SP and SPMA would be transferred into its ring-opening merocyanine Herein, a class of novel photoswitchable tristate fluorescent polymeric nanoparticles (TS-PFPNs) consisting of a well-designed perylenediimide-spiropyran conjugate (PDI-SP), two energy-matched photochromics as spiropyran-linked methacrylate and diarylethene (DTE) derivative (DTEo-1) is described. By optimizing the feed ratio ...

Single-Molecule Junction: A Reliable Platform for Monitoring Molecular Physical and Chemical Processes

“…Spiropyrans have been widely used in the construction of functional monomolecular devices over the past decades because of their intrinsic molecular advantages. − Ring-closed SP can be transformed into zwitterionic merocyanine (MC) in the ring-open state, and conjugation is absent between the two heterocycles in the ring-closed molecular structure. SP can be transformed into MC through accurate regulation of the external force.…”

Spiropyran-incorporated honeycomb porous films with reversible multistimuli-responsive properties

“…[6][7][8] Accordingly, various types of stimulusresponsive molecules including azobenzene, phenoxyquinone, bisthienylethene and spiropyran (SP) derivatives have been explored so far. [9][10][11] Isomerization processes such as cis/trans isomerization, ring opening/closure, and phenyl group migration of these molecules upon external stimuli were able to induce changes in the material properties. [12][13][14] Among them, SP derivatives have garnered great attention due to their facile synthesis, excellent fatigue resistance and distinct chromic transition towards diverse stimuli.…”

“…6–8 Accordingly, various types of stimulus-responsive molecules including azobenzene, phenoxyquinone, bisthienylethene and spiropyran (SP) derivatives have been explored so far. 9–11 Isomerization processes such as cis / trans isomerization, ring opening/closure, and phenyl group migration of these molecules upon external stimuli were able to induce changes in the material properties. 12–14…”

Electrostatic Assembly of Photochromic TiO2/Phosphomolybdic Acid Composite Nanoparticles for Light-Responsive Rewritable Papers

“…Although our ways of communication and information storage have been greatly changed in modern digital age, paper prints still occupy a crucial role in daily life according to international surveys that annual paper production shows sustained growth and is estimated to be 900 million tonnes in 2050. − However, most papers for nonstorage prints are disposed in a short period of one-time reading, which causes huge environmental problems, energy consumption, and business operating cost. , Rewritable paper, which can be reused for multiple times, is an appealing alternative approach to alleviating these problems. Various stimuli-responsive materials/systems that are capable of undergoing reversible color changes in response to light, − heat, − pH, , water, , mechanical force, and other solvents have been developed as imaging media for rewritable paper. Among them, light-printable rewritable paper (LRP) has been one of the most popular research areas because light as an external stimulus has advantages of cleanliness, green property, easy handling, high resolution, and favorable noncontact writing. , Tremendous efforts have recently been devoted to develop several photochromic materials/systems, which are the core to fabricate LRP.…”