| Naphthopyrans, which are an important class of photochromic dyes, attract muchattention and motivate interesting research in recent years. In addition, naphthopyranshave the advantages in commercial application in light-sensitive ophthalmic lenses,optical memories, optical and electrical switching and light-actuated nanovalves dueto their special optical properties, such as the fine control over fading kinetics andgood resistance to photochemical fatigue.In this thesis, we fabricated the layer-by-layer assembled films containingnaphthopyrans, and aimed at enhancing the photochromic properties of naphthopyransfor potential applications. The properties of the films were well characterized by theUV-Vis, FT-IR, and AFM. In addition, the photochromic materials of single-moleculeNP were used as the hydrophobic and light-responsive group to fabricate micelles.The surface morphology and the light-responsive properties of micelles were wellcharacterized by UV-Vis, Transmission Electron Microscopy (TEM), Dynamic lightScattering (DLS) and Fluorescence Spectra. The main contents of this dissertation areas following:1. A photochromic polymer film has been fabricated by the layer-by-layer (LBL)self-assembly through alternating the deposition of poly(acrylic acid) bearing anaphthopyran copolymer(PAA-NP) and poly(4-vinylpyridine)(P4VP) in an organicsolvent via H-bond. The multilayer assembly process and surface morphology weremonitored via UV-Vis, FT-IR, AFM. The results reveal that the multilayer films growin a uniform way in each deposition, and the surface was relatively smooth. Thephotochromic properties of the naphthopyran in the LBL films were investigated andthe kinetic results confirm that the colored merocyanine in the LBL films show asignificant slow fading speed (critical T1/2decoloration time increased to64min inthe3-bilayer film) and are more stable than those in previous reports. Finally, weconfirmed the reversibility of coloration and decoloration at481nm. After5cycles ofcoloration/decoloration, the coloration of naphthopyran was not complete, thereappeared to be minor degradation.2. The photochromic materials of single-molecule naphthopyrans(NP) were usedas hydrophobic and light-responsive group to synthesize amphiphilic polymer withthe poly(ethylene glycol)(PEG) via Click-Chemistry. Such an amphiphilic polymer can self-assemble to light-responsive micelles with NP-core and PEG-shell in aqueoussolution, as were confirmed by DLS and TEM. The photoisomerization ofnaphthopyrans moieties can fast and reversibly tune the disassembly and re-assemblyof the micelle, as were confirmed by UV-Vis spectroscopy. The changes offluorescent spectra of nile red (NR) in water solution of polymeric micelle within60sdemonstrate that the polymeric micelle can be used as nanocarriers to encapsulate,release and re-encapsulate guest solutes on demand controlling of light irradiation.Moreover, we have tried three cycles to confirm the reversibility of encapsulation andrelease, the result shows a particularly good fatigue resistance. The fast and highlyefficient photo-control of polymeric micelles is a potential candidate in biomedicalarea for drug delivery.3. We designed and synthesized a bifunctional naphthopyran derivative withnegative-charged di-sulfatoethoxy: DSNP. Firstly, DSNP can be used to prepare theLBL self-assembly films by dipping charged substrates alternately into aqueoussolutions of cationic quaternized poly(4-vinylpyridine)(P4VPQ) and anionic DSNP.The multilayer assembly process was monitored via UV-Vis, The results reveal thatthe multilayer films grow in a uniform way in each deposition. The photochromicproperties of the naphthopyran in the LBL films were investigated and the kineticresults confirm that the trend of fading speed is as following: NP in THF> NP inother polymeric matrix> NP in LBL self-assembly films via ionic-bond> NP in LBLself-assembly films via H-bond. Secondly, DSNP also can be used as thelight-responsive group to fabricate light-responsive micelles with polyethyleneglycol-triethylamine bromide (PEG-NEt3), as were confirmed by TEM. Thephotoisomerization of naphthopyrans moieties can fast and reversibly tune thedisassembly and re-assembly of the micelle, as were confirmed by UV-Visspectroscopy. The changes of fluorescent spectra of nile red (NR) in water solution ofpolymeric micelle demonstrate that the polymeric micelle can be used as nanocarriersto encapsulate, release and re-encapsulate guest solutes on demand controlling of lightirradiation. Moreover, we have tried three cycles to confirm the reversibility ofencapsulation and release, the result shows a particularly good fatigue resistance. |
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