Preparation of a spirooxazine grafted PMMA and its photochromic properties

A novel spirooxazine (SO) compound was designed and synthesized. Macromolecular materials, called SO-g-hPMMAs (where the g means grafting and the h means partial hydrolysis), were prepared using PMMA (polymethylmethacrylate) with different degrees of hydrolysis. SO-g-5%hPMMA was prepared by reacting SO-containing active C-Br bonds with 5% partially hydrolyzed PMMA. The SO was characterized using ¹H NMR and infrared. Beyond that, photochromic properties were studied in detail. We discuss the effects of hydrochloric acids and hPMMAs of different hydrolysis degrees on photochromic properties of SO-g-hPMMA. Additionally, mechanical properties of the material were studied. Results indicate that the colored ring-opening form (PMC) of SO-g-hPMMA exhibits a good performance in terms of thermal stability, in contrast to the homologous SO. Experiments additionally demonstrate that hydrochloric acid improves the PMC’s thermal stability. SO-g-9%hPMMA demonstrated a good performance of photochromic properties compared to those with different degrees of hydrolysis.     

具有双荧光发射的螺吡喃的合成与性质研究

设计合成了未见文献报道的含有双官能团的螺吡喃类化合物1,通过红外光谱、核磁共振氢谱、碳谱和高分辨质谱对其结构进行了确证。紫外可见吸收光谱表明化合物在有机溶剂中的光致变色性良好;化合物的乙醇溶液在365 nm光激发时产生双荧光发射,分别为闭环体和开环体所对应的的荧光峰。本文首次从场效应角度推测了螺吡喃吲哚林N原子上含有极性基团时开环体稳定的原因。     

UV-induced self-assembly of the inclusion complexes formed between a long-chain photochromic spiropyran and cyclodextrins

Photochromic spiropyran with a long chain alkyl substitute can form axial complexes with α-, β-, and γ-cyclodextrin, respectively. The complexes show normal photochromism. The novel property of the colored forms of the inclusion complexes is that they can assemble into dimers at relatively low concentration or J-aggregates at relatively high concentration. For α-, β-, and γ-cyclodextrin, λ_(max) of the J-aggregates appear at 700 650, and 630 nm, respectively. The sizes of the cavities of cyclodextrins have very little effect on the spectra and decoloration kinetics of the dimers, but have great effects on the spectra of the J-aggregates. Unlike the charge transfer complex of Krongauz, the decoloration process of the dimers or J-aggregates cannot be described by an exponential or a two-exponential kinetics, but obey half-order kinetics very well. Another result that can be deduced from the kinetic analysis is that unlike the dimers formed in apolar solvents or in polymers, which consist of a color     

Synthesis and properties of photochromic liquid-crystalline polyacrylates containing a spirooxazine group

The novel photochromic liquid-crystalline polyacrylates containing a spirooxazine group were synthesized. The photochromic polymer containing (4-penta- methyleneoxy)biphenylene moiety at the 5-position of spironaphthoxazine showed nematic phase from 122.9 to 133.8°C. The photochromic polymer containing undeca- methylene instead of pentamethylene showed smectic phase from 93.1 to 169.7°C. On the other hand, the photochromic polymer containing both undecamethylene as a spacer and spironaphthoxazine-bound biphenylene moiety at 9′-position did not show any liquid crystallinity. All spirooxazine-containing liquid-crystalline polymers showed photochromism in the solid state at room temperature. Because the shape of the absorption spectra of the photochromic quenched liquid-crystalline polymer films was almost the same as those of the photochromic amorphous polymer films, the photochromic properties did not depend on the mesophase in the polymers examined. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3513–3522, 1999     

Polymeric siloxanes with a substituent and the spirobenzopyran moiety: Effect of polar substituent on the photochromic properties

Oligomeric polysiloxanes having the spirobenzopyran moiety and various substituents were prepared. The polymers were photochromic; the color changed from colorless to red on UV irradiation and the color faded on visible irradiation or on standing in the dark. The thermal decoloration was depressed by the polar substituents. However, the effect of the bulky substituent, which had been observed in the rigid siloxane resins, was not detected. In the inorganic/organic hybrid siloxane gels, the silica/(spirobenzopyran-bonding polysiloxane) system and the (spirobenzopyran-bonding silica)/polysiloxane system, the thermal decoloration was also affected by the polar substituent introduced into the polysiloxane portion. The effect was larger in the first case than in the second. The result can be interpreted by the term of the preferential diffusion of polar spirobenzopyran to the vicinity of the polar substituents during the gelation.     

Thermodynamic and transport properties of polyhedral oligomeric sislesquioxanes in poly(dimethylsiloxane)

Polyhedral oligomeric silsesquioxane (POSS) molecules when functionalized appropriately and dispersed in polymers show promise as monodisperse organic-inorganic hybrid nanocomposite materials characterized by superior mechanical properties. We report here molecular-simulation results for POSS-POSS radial distribution functions, potentials of mean force, and self-diffusion coefficients for POSS monomers dissolved in poly(dimethylsiloxane) in the temperature range of 300-1000 K. Our results demonstrate that it is possible to modulate the effective POSS-POSS interaction by increasing the temperature or by substituting the hydrogen atoms in the POSS monomer with methyl groups. In addition, our results indicate that the motion of POSS monomers dissolved in poly(dimethylsiloxane) follows a hopping mechanism.     

Synthesis, characterization and photochromic studies of spirooxazine-containing 2,2'-bipyridine ligands and their rhenium(I) tricarbonyl complexes

A series of spirooxazine-containing 2,2'-bipyridine ligands and their rhenium(i) tricarbonyl complexes has been designed and synthesized, and their photophysical, photochromic and electrochemical properties have been studied. The X-ray crystal structures of two of the complexes have been determined. Detailed studies showed that the emission properties of the complexes could readily be switched through photochromic reactions.     

Synthesis and photochromic properties of spiro (benzindoline-naphthoxazines)

A new photochromic compound belonging to the class of spiro(indoline-naphthoxazines) was synthesized. Nitration of this compound was carried out and the structures of two photochromic nitro-substituted products were determined. The photochromic properties of the products were studied in solvents of different polarity.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 732–736, April, 1995.     

侧链可降解聚硅氧烷的合成及其膜性能

以乳酸和聚乙二醇为原料,直接缩聚法制备出聚乳酸-聚乙二醇可降解嵌段共聚物,再将烯丙基缩水甘油醚和所得的嵌段共聚物在锌粉的作用下得到带有α烯基反应性官能团的大分子单体,然后在铂催化剂的作用下,合成了一种带有可降解侧链的亲水性聚硅氧烷(PDMS-g-PLA-PEG).对产物的结构、相对分子质量及其分布、热性能及成膜的表面性能等进行了研究.结果表明,由于分子链中硅氢键分布的不均匀性和聚乳酸-聚乙二醇共聚物分子量分布的不均一性,产物的分子量分布相对较宽,达到了1.87.由于聚乳酸-聚乙二醇共聚物侧链逐渐降解,所以PDMS-g-PLA-PEG所成的膜与水的接触角将随着时间的延长而逐渐增大,30天后从42°增至92°.     

Preparation and photochromic properties of dye-doped aluminosilicate and ORMOCER gels and coatings

Aluminosilicate and ORMOCER gels and coatings containing photochromic dyes, 1, 3-dihydro-1, 3, 3-trimethylspiro-[2H-indole-2, 3-[3H]-naphth-[2, 1-b][1, 4]-oxazine] (SO) and 1, 8a-dihydro-2, 3-dimethoxycarbonyl-spiro [fluorene-9, 1-indolizine] (DHI), were prepared by the sol-gel method and the photochromic activity was monitored in the course of the sol-wetgel-xerogel transformation. The photochromic activity of the aluminosilicate gels decreases rapidly and even vanishes in the wetgel-xerogel stage while that of ORMOCER gels and coatings levels off in the early wetgel-xerogel stage at a reasonably high photochromic intensity with the colour-fading speed similar to that in ethanol and the photostability being considerably improved. The experimental results are discussed in terms of the matrix effect on photochromism of organic dyes.     

Synthesis and properties of phthalonitrile-terminated oligomeric poly(ether imide)s containing phthalazinone moiety

Three novel series of soluble and curable phthalonitrile-terminated oligomeric poly(ether imide)s containing phthalazinone moiety were synthesized from an excess amount of three dianhydrides and phthalazinone-based diamine, followed by reacting with 4-(3-aminophenoxy)phthalonitrile (APPh) in a two-step, one-pot reaction, respectively. The phthalonitrile oligomers containing phthalazinone moiety were cured in the presence of 4,4′-diaminodiphenylsulfone (DDS). The oligomers and the crosslinked polymers were characterized by DSC, FT-IR and elemental analysis. These phthalonitrile oligomers containing phthalazinone groups were found to be soluble in some aprotic solvents, such as chloroform, pyridine, m-cresol and N-methyl-2-pyrrolidone (NMP). The crosslinked polymers were insoluble in all solvents. The thermal properties of the oligomers and the crosslinked polymers were evaluated using DSC and TGA analysis. The phthalonitrile oligomers showed high glass transition temperatures (T_gs) in the range of 214-256 °C and high decomposition temperatures with 10% weight loss (T_d10%) ranging from 523 to 553 °C. The crosslinked polymers showed excellent thermal stability with the 10% weight loss temperatures ranging from 543 to 595 °C, but did not exhibit a glass transition temperature upon heating to 350 °C.     

Synthesis and thermal characterization of novel poly(tetramethyl‐1,3‐silphenylenesiloxane) derivative with phenol moiety in the main chain

Novel poly(tetramethyl‐1,3‐silphenylenesiloxane) derivative with phenol moiety in the main chain, that is, poly(tetramethyl‐5‐hydroxy‐1,3‐silphenylenesiloxane) ( P1 ), was synthesized and the thermal properties were investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG). P1 was obtained via deprotective hydrogenation of poly(tetramethyl‐5‐benzyloxy‐1,3‐silphenylenesiloxane) ( Pre‐P1 ) catalyzed by 10% palladium on charcoal as well as via direct polycondensation of 3,5‐bis(dimethylhydroxysilyl)phenol ( M2 ). Pre‐P1 was obtained by polycondensation of 1,3‐bis(dimethylhydroxysilyl)‐5‐benzyloxybenzene ( M1 ), catalyzed by 1,1,3,3‐tetramethylguanidinium 2‐ethylhexoate. M1 was prepared by the Grignard reaction using chlorodimethylsilane and 1,3‐dibromo‐5‐benzyloxybenzene followed by the hydrolysis catalyzed by 5% palladium on charcoal. M2 was prepared by deprotective hydrogenation of M1 catalyzed by 10% palladium on charcoal. The obtained P1 was soluble in common organic solvents such as tetrahydrofuran, chloroform, dichloromethane, toluene, and so forth as well as in highly polar solvents as ethanol and methanol in which poly(tetramethyl‐1,3‐silphenylenesiloxane) is insoluble. The glass transition temperature (T_g) of P1 was determined to be 40 °C from DSC, which was much higher than that of poly(tetramethyl‐1,3‐silphenylenesiloxane) (?52 °C), indicating that the intermolecular and/or intramolecular hydrogen bondings based on hydroxyl groups restricted the mobility of the main chain. The temperature at 5% weight loss (T_d5) of P1 (393 °C) determined by TG was lower than that of poly(tetramethyl‐1,3‐silphenylenesiloxane) (ca. 500 °C), indicating that the phenol moieties decline the thermal stability; however, the obtained P1 would promise to be a new reactive‐polymer with phenolic–hydroxyl moieties to develop new functional materials. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 692–701, 2008     

Synthesis and crosslinking reaction of poly(thiourethane)s having a siloxane moiety in the side chain

Poly(thiourethane)s having a siloxane moiety in the side chain were synthesized with a 5‐membered cyclic dithiocarbonate (DTC) having a siloxane group as a building block. The synthetic pathway consisted of (1) an addition reaction of the DTC with diamines and (2) polyaddition reactions of the resulting dithiols with diisocyanates. The siloxane moiety in the polymer side chain underwent a self‐condensation reaction upon exposure to moisture, and this led to a successful crosslinking reaction of the poly(thiourethane). The crosslinking on a silicate surface was accompanied by condensation between the siloxane side chain of the polymer and the silanol group on the surface, giving the corresponding surface that was permanently coated with the crosslinked polymer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6492–6502, 2005     

Photo- and thermochromic spiranes 32*. Synthesis and photochromism of 3-methyl-4-oxospiro(2,3-dihydronaphtho-[2,1-<Emphasis Type="Italic">e</Emphasis>]-1,3-oxazine-2,2'-[2H]-chromenes)

Spiropyrans of the naphthoxazinone series have been obtained containing various substituents in the [2H]-chromene portion of the molecule. The spatial structure of a spiropyran containing ortho-positioned hydroxyl and formyl groups was established by X-ray structural analysis. The photochromic properties of the obtained compounds have been studied. For Communication 31 see [1]. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 273-283, February, 2009.     

Synthesis and characterization of poly(benzobisthiazole) with tetramethylbiphenyl moiety in the main chain

Poly(benzobisthiazole)s containing an ortho-tetramethyl substituted biphenyl moiety were synthesized via the polycondensation of 2,5-diamino-1,4-benzenedithiol dihydrochloride with 2,2′,6,6′-tetramethylbiphenyl-4,4′-dicarboxylic acid in poly(phosphoric acid) (PPA). The intrinsic viscosities of the tetramethylbiphenyl poly-(benzobisthiazole)s in chlorosulfonic acid at 30°C were in the range of 6.9–13.4 dL/g. Copolycondensation of 2,5-diamino-1,4-benzenedithiol dihydrochloride with terephthalic acid and 2,2′,6,6′-tetramethylbiphenyl-4,4′-dicarboxylic acid was carried out as well by varying the ratio of the two dicarboxylic acid monomers in the reactant mixture. The homopolymers and copolymers were characterized by Fourier transform infrared spectroscopy (FTIR) and ¹³C solid-state nuclear magnetic resonance spectroscopy (NMR). Thermal stability of the polymers was evaluated by thermogravimetric analysis (TGA) and thermogravimetric mass spectrum analysis (TG-MS). The tetramethylbiphenyl poly(benzobisthiazole)s were found to be more stable at elevated temperatures than the parent poly(p-phenylene benzobisthiazole) (PBZT). © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1407–1416, 1998     

Tailoring the surface properties of poly(dimethylsiloxane) microfluidic devices

Poly(dimethylsiloxane) (PDMS) is an attractive material for microelectrophoretic applications because of its ease of fabrication, low cost, and optical transparency. However, its use remains limited compared to that of glass. A major reason is the difficulty of tailoring the surface properties of PDMS. We demonstrate UV grafting of co-mixed monomers to customize the surface properties of PDMS microfluidic channels in a simple one-step process. By co-mixing a neutral monomer with a charged monomer in different ratios, properties between those of the neutral monomer and those of the charged monomer could be selected. Mixtures of four different neutral monomers and two different charged monomers were grafted onto PDMS surfaces. Functional microchannels were fabricated from PDMS halves grafted with each of the different mixtures. By varying the concentration of the charged monomer, microchannels with electrophoretic mobilities between +4 x 10(-4) cm2/(V s) and -2 x 10(-4) cm2/(V s) were attainable. In addition, both the contact angle of the coated surfaces and the electrophoretic mobility of the coated microchannels were stable over time and upon exposure to air. By carefully selecting mixtures ofmonomers with the appropriate properties, it may be possible to tailor the surface of PDMS for a large number of different applications.     

Preparation and characterization of a novel poly(1,4-phenylenevinylene) derivative with an azobenzene side chain

A novel poly(1,4-phenylenevinylene) (PPV) derivative containing an azobenzene side chain was prepared via a dehydrochlorination route. Poly{2-methoxy-5-[(4-(4-methoxyphenylazo)phenyloxy)-hexyloxy]-1,4-phenylenevinylene}, which is soluble in ordinary solvents such as chloroform, tetrahydrofuran (THF), acetone, xylene, etc., was characterized by FTIR, ¹H NMR, GPC, and UV-visible spectroscopies, thermogravimetric analysis (TGA), and cyclic voltammetry. The photoluminescence spectrum of the polymer showed an emission maximum at λ = 550 nm.     

Connecting the wetting and rheological behaviors of poly(dimethylsiloxane)-grafted silica spheres in poly(dimethylsiloxane) melts

Using dynamic light scattering, mechanical rheometry, and visual observation, the static wetting behavior of PDMS-grafted silica spheres (PDMS-g-silica) in PDMS melts is related to their rheology. A phase diagram is mapped out for a constant grafted chain length as a function of grafting density and free polymer chain length. The transition between stable and aggregated regions is determined optically and with dynamic light scattering. It is associated with a first-order wetting transition. In the stable region Newtonian behavior is observed for semidilute suspensions. The hydrodynamic brush thicknesses, deduced from viscosity measurements, correspond closely to values obtained from self-consistent field calculations for the various parameter values. At the transition, the brush collapses suddenly and shear-thinning and thixotropy appear. The rheology indicates a degree of aggregation that increases with increasing length of the free polymer, as suggested by the theory.