Polymerizable Solutions Research Articles

Waterproof Light‐Emitting Metal Halide Perovskite–Polymer Composite Microparticles Prepared via Microfluidic Device

AbstractWaterproof light‐emitting perovskite–polymer composite microparticles are synthesized by a continuous one‐step microfluidic reactor, which enables in situ production of metal halide perovskite nanoparticles (MHP‐NPs) by the ligand‐assisted reprecipitation process (LARP) and the encapsulation of MHP‐NPs by UV cross‐linking polymerization in the microfluidic channel. Successful encapsulation of MHP‐NPs in polymer microparticles is attributed to the co‐dispersion of an LARP solution and UV polymerizable solution in an aqueous continuous phase within the microfluidic channel, in which N,N‐dimethylformamide, in co‐dispersion droplets, is continuously extracted to the aqueous medium upon UV polymerization. MHP‐NPs–polymer composite microparticles show enhanced stability against air and moisture.

Chemical and Topographical Modification of Polycarbonate Surfaces through Diffusion/Photocuring Processes of Hydrogel Precursors Based on Vinylpyrrolidone.

Facile procedures capable of simultaneously conferring hydrophilicity and tailored topography to surfaces of hydrophobic supports, such as polycarbonate (PC), are very attractive but rare. In this work, we describe a simple methodology to wrinkle PC surfaces after a process of (a) contacting with a photopolymerizable vinylic solution, (b) UV curing of such solutions, and (c) detachment of the formed polymer network, upon swelling in ethanol. The influence of different parameters such as contact lag time between the PC surface and the polymerizable solution, the monomer concentration and type of solvents, as well as the cross-linking degree on the formation of wrinkles, has been studied. The dimensions of the wrinkles can be tailored to some extent by altering the different parameters. Surface chemistry has been analyzed by contact angle measurements and by confocal Raman microscopy. The results are consistent with a chemical alteration of the surface and the formation of an outer hydrogel layer, which is interpenetrated into the PC structure. A mechanism of monomer diffusion and PC swelling that produces surface instabilities and wrinkling is proposed.

Two-Color Single Hybrid Plasmonic Nanoemitters with Real Time Switchable Dominant Emission Wavelength

We demonstrate two-color nanoemitters that enable the selection of the dominant emitting wavelength by varying the polarization of excitation light. The nanoemitters were fabricated via surface plasmon-triggered two-photon polymerization. By using two polymerizable solutions with different quantum dots, emitters of different colors can be positioned selectively in different orientations in the close vicinity of the metal nanoparticles. The dominant emission wavelength of the metal/polymer anisotropic hybrid nanoemitter thus can be selected by altering the incident polarization.

Flow behavior of polymerizable ceramic suspensions as function of ceramic volume fraction and temperature

The effect of volume fraction and temperature on flow behavior is reported for suspensions of coarse silica powders in two non-aqueous polymerizable solutions. The concentration dependence of the viscosity at temperatures 25–75 °C can be reduced to a single Krieger–Dougherty curve for all suspensions. The temperature dependence of viscosity for suspensions with 60 vol% silica could be fit to an Arrhenius equation. The suspensions had a larger apparent activation energy than the suspension medium. This could be explained in terms of thermal dilution, where the higher thermal expansion of the liquid reduces the solids loading for very concentrated suspensions.

Self-Assembly of Rod-Coil Molecules in a Polymerizable Solution

O WILEY-VCH Verlag GmbH, D-69469 Weinheim, 1999 0935-9648/99/1208-1018 $ 17.50+.50/0 Adv. Mater. 1999, 11, No. 12[13] G. Schmid, V. Maihack, F. Lantermann, S. Peschel, J. Chem. Soc., Dal-ton Trans. 1996, 589.[14] A. Corma, A. Martinez, V. Martinez-Soria, J. Catal. 1997, 169, 480.[15] M. Ichikawa, T. Yamamoto, W. Pan, T. Shido, Studies Surf. Sci. Catal.1997, 105, 679.[16] U. Junges, F. Schuth, G. Schmid, Y. Uchida, R. Schlogl, Ber. Bunsenges.Phys. Chem. 1997, 11, 1631.[17] D. S. Shephard, T. Maschmeyer, B. F. G. Johnson, J. M. Thomas, G.Sanker, D. Ozkaya, W. Zhou, R. D. Oldroyd, Angew. Chem. Int. Ed.1997, 36, 2242.[18] D. Tas, R. F. Parton, K. Vercruysee, P.A. Jacobs, Studies Surf. Sci. Cat.1997, 169, 480.[19] C. P. Mehnert, J. Y. Ying, J. Chem Soc., Chem. Commun. 1997, 22,2215.[20] M. Antonietti, Angew. Chem. Int. Ed. Engl. 1988, 27, 1743[21] M. Antonietti, F. Grohn, J. Hartmann, L. Bronstein, Angew. Chem.Int. Ed. 1997, 36, 2080.[22] M. Antonietti, B. Berton, C. Goltner, H-P. Hentze, Adv. Mater. 1998,10, 154.[23] J. P. Spatz, S. Mossmer, M. Moller, Chem. Eur. J. 1996, 2, 1552.[24] S. Klingelhofer, W. Heitz, A. Greiner, S. Oestreich, S. Forster, M. An-tonietti, J. Am. Chem. Soc. 1997, 119, 10116.[25] M. Serigina, L. Bronstein, O.A. Platonova, D. M. Chernyshov, P. M.Valetsky, E. Wenz, J. Hartmann, M. Antonietti, Chem. Mater. 1997, 9,923.[26] A. B. R. Mayer, J.E. Mark, R.E. Morris, Polym. J. 1998, 30, 197.[27] A. Antonietti, A. Briel, S. Forster, J. Chem. Phys. 1996, 105, 7795.

Preparation and Characterization of (Ba,Ca)(Ti,Zr)O3 Thin Films Through Sol-Gel Processing

(Ba0.92,Ca0.08)(Ti0.92,Zr0.08)O3 thin films were prepared from Ba-Ti and Ca-Zr precursors by sol-gel processing. Polymerizable solutions containing Ba-Ti and Ca-Zr, respectively, were newly synthesized. Decomposition of the starting compounds and crystallization behavior of the film were examined by using TG/DTA and XRD. Microstructure of thin films was observed by using SEM. Polycrystalline (Ba0.92,Ca0.08)(Ti0.92, Zr0.08)O3 films obtained by firing at 800°C were dense with fine grains. The thin films showed a dielectric constant of 1200 and dielectric loss of 0.5%.

A two-step embedding process for better preservation of soft tissue surrounding coral implants.

Infiltration of paraffin or embedding polymers proceeds more quickly in soft than in mineralized tissue specimens (bone or biomaterial). The proposed method takes advantage of this difference to protect soft tissue from the action of decalcifying agents. After embedding a bone-soft-tissue sample in a hydrophobic polymer, it is cleared of the resin on one of its sides to permit access of the decalcifying solution to the mineral component. A second infiltration with another polymerizable solution that cures in the empty pores created by the dissolution makes it possible to obtain a homogeneous hard block, make thin slices, and perform enzyme histochemistry and immunostaining on well-preserved soft tissue with most of its antigenic and enzymatic properties intact.

Ferroelectric Properties and Fatigue Characteristics of Bi4Ti3O12 Thin Films by Sol-Gel Processing

Stoichiometric Bi4Ti3O12 thin films were prepared by sol-gel processing. This paper discusses the synthesis of polymerizable solutions containing Bi and Ti, ferroelectric properties and fatigue characteristics of the resulting Bi4Ti3O12 thin films. The complex alkoxide was prepared by allowing Bi acetate to react with Ti alkoxides. Bismuth acetate and titanium methoxyethoxide, the solvents 2-methoxyethanol and glacial acetic acid were selected based on their successful use in a number of related systems. Thin films of Bi4Ti3O12 were obtained onto platinized Si substrates by spin casting, followed by heat treated at 700° C. The value of the dielectric constant and loss at 400 Hz, 100 mVrms, 25° C of this virgin films were 132 and 0.8%, respectively. This thin films with single phase layerd perovskite-like structure had very good D-E hysteresis characteristics. The remnant polarization, P r, and coercive field, E c, of this virgin films were 5.5 µ C/cm2 and 6.2 kV/cm, respectively. The remnant polarization of this thin films, P r+, P r-, and 2P r, were nearly constant up to 108 cycles. At 4×108 cycles, the decay in remnant polarization, P r+, P r-, and 2P r, was observed to be about 35% of the initial values, respectively. The coercive field was drastically increased after 108 cycles. The D-E hysteresis loop after 108 cycles was not completely saturated. After 108 cycles, leakage current was typically increased. We considered that the fatigue characteristics observed in our study are resulted from increasing of leakage current.

Synthesis and Characterization of Bi4Ti3O12 Thin Films by Sol-Gel Processing

Stoichiometric Bi4Ti3O12 thin films were prepared by sol-gel processing. This paper discusses the synthesis of polymerizable solutions containing Bi and Ti, and characterization of the resulting Bi4Ti3O12 thin films. The formation of metallic alkoxide and acetate alkoxide are indispensable, soluble precursors for these multicomponent systems. The double alkoxide was prepared by allowing Bi acetate to react with Ti alkoxides. The development of the polymerizable solution system containing Bi and Ti required choosing appropriate solvents and metallo-organic sources for the two components. Bismuth acetate, titanium methoxyethoxide and the solvents 2-methoxyethanol and glacial acetic acid were selected based on their successful use in a number of related systems. Thin films of Bi4Ti3O12 were obtained onto platinized Si substrates by spin casting, followed by heat-treated at 700°C. These films were later characterized by X-ray diffraction and SEM. The measured dielectric and ferroelectric properties of Bi4Ti3O12 were as follows: dielectric constant 120, dielectric loss 0.5%, remanent polarization Pr=4 µC/cm2, coercive field Ec=1.8 kV/cm.