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1.
Polymers (Basel) ; 9(8)2017 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-30971016

RESUMO

In this study, we synthesized amphiphilic poly(2,7⁻(9,9⁻dioctylfluorene))⁻block⁻N,N⁻(diisopropylamino)ethyl methacrylate (POF⁻b⁻PDPMAEMA) rod-coil diblock copolymers by atom transfer radical polymerization (ATRP). The structure and multifunctional sensing properties of these copolymers were also investigated. The POF rod segment length of 10 was fixed and the PDPAEMA coil segment lengths of 90 and 197 were changed, respectively. The micellar aggregates of POF10⁻b⁻PDPAEMA90 rod-coil diblock copolymer in water showed a reversible shape transition from cylinder bundles to spheres when the temperature was changed from 20 to 80 °C or the pH was changed from 11 to 2. The atomic force microscopy (AFM) and transmission electron microscopy (TEM) measurements indicated that the temperature had also an obvious influence on the micelle size. In addition, since POF10⁻b⁻PDPAEMA90 had a lower critical solution temperature, its photoluminescence (PL) intensity in water is thermoreversible. The PL spectra showed that the POF⁻b⁻PDPAEMA copolymer had a reversible on/off profile at elevated temperatures, and thus could be used as an on/off fluorescent indicator for temperature or pH. The fluorescence intensity distribution of pH switched from "off⁻on" to "on⁻off" as the temperature increased. These results showed that the POF⁻b⁻PDPAEMA copolymer has a potential application for temperature and pH sensing materials.

2.
J Nanosci Nanotechnol ; 10(7): 4573-80, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21128459

RESUMO

Nanoporous silica films were prepared through the templating of amphiphilic block copolymer, poly(styrene-2-vinyl pyridine) (PS-b-P2VP), and monodispersed colloidal silica nanoparticles. The experimental and theoretical studies suggested that the intermolecular hydrogen bonding existes between the colloidal silica nanoparticles and PS-b-P2VP. The effects of the loading ratio and P2VP chain length on the morphology and properties of the prepared nanoporous silica films were investigated. TEM and AFM studies showed that the uniform pore size could be achieved and the pore size increased with increasing porogen loading. The refractive index and dielectric constant of the prepared nanoporous films decreased with an increase in PS-b-P2VP loading. On the other hand, the porosity increased with an increasing PS-b-P2VP loading. This study demonstrated a methodology to control pore morphology and properties of the nanoporous silica films through the templating of PS-b-P2VP.

3.
J Nanosci Nanotechnol ; 10(8): 5359-63, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21125898

RESUMO

In this study, poly(4,4-(hexafluoroisopropylidenediphthalic anhydride)-co-oxydianiline) (6FDA-ODA) and a novel core-shell nanoparticle consisting of a core (SnO2/TiO2) and a shell (ZrO2/Sb2O3) with the composition (SnO2:TiO2:ZrO2:Sb2O3 = 18:5:3:4) were used to prepare polyimide/nanoparticles hybrid thin films. The resultant hybrid thin films were investigated by FTIR, TGA, DSC, TEM, SEM, AFM, alpha-step, UV-Vis, and n&k analyses. The results show that the prepared hybrid thin films had a good thermal stability. The size of nanoparticles was effectively controlled in the range of 8-10 nm in the hybrid thin films. These nanoparticles were evenly distributed across the hybrid thin films and no phase separation occurred. In terms of the optical properties, the prepared hybrid thin films had good transparency in the range of visible light. The cutoff wavelength had a blue shift as the content of the nanoparticles increased. The refractive index of prepared hybrid thin films increased with corresponding increases in nanoparticle content. Moreover, the prepared polyimide/core-shell nanoparticle hybrid thin films displayed excellent film formability and planarity.

4.
J Nanosci Nanotechnol ; 10(8): 5364-8, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21125899

RESUMO

In this study, poly(acrylic)/SiO2/EuL3 x 2H2O hybrid thin films were prepared from various acrylic monomers (MMA and EDMA/TMPTA), lanthanide metal complexes (EuL3 x 2H2O, L = pyridine carboxylic acid), and monodispersed colloidal silica with a coupling agent, 3-(trimethoxysilyl)propyl methacrylate (MSMA). It is a combination of the sol-gel reaction, thermal polymerization, and spin coating. The silica content in the hybrid thin films is fixed at 20 wt%, and the EuL3 x 2H2O content is varied from 0.01 g to 0.07 g. FTIR and EA analysis confirms the chemical structure of the prepared EuL3 x 2H2O and poly(acrylic)/SiO2/EuL3 x 2H2O hybrid thin films. UV-Vis spectra and n&k analysis shows that the hybrid thin film has good transparency in visible light. The refractive index of hybrid thin films can be effectively controlled through the EuL3 x 2H2O content. The PL spectra shows that the strongest emission peak occurs at 615 nm and the emission intensity increases to the peak maximum at an EuL3 x 2H2O content of 0.05 g. Both TGA and PL analysis show that the prepared hybrid thin films from the crosslinked acrylic polymer moiety have much better film uniformity, thermal stability, and fluorescence properties. The TEM diagram shows that the MSMA/SiO2/EuL3 x 2H2O particles with a size 15-20 nm are well dispersed in the reaction solution. The SEM diagram shows that the particle distribution in the prepared hybrid thin films is uniform and no phase separation is observed. Finally, AFM analysis indicates that the prepared hybrid thin films have an excellent surface planarity.

5.
J Nanosci Nanotechnol ; 9(7): 4040-7, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19916406

RESUMO

In this study, poly(acrylic)/SiO2/EuL3 x 2H2O hybrid thin films were prepared from various acrylic monomers (MMA and EDMA/TMPTA), lanthanide metal complexs (EuL3 x 2H2O, L = pyridine carboxylic acid), and monodispersed colloidal silica with a coupling agent, 3-(trimethoxysilyl)propyl methacrylate (MSMA). It was a combination of the sol-gel reaction, thermal polymerization, and spin coating. The EuL3 x 2H2O content in the hybrid thin films was fixed at 0.05 g and silica content was varied from 10 to 50 wt%. TEM results showed that both SiO2 and EuL3 x 2H2O were well dispersed in the hybrid thin films without aggregation. PL spectra showed the unique emission of Eu3+. The addition of SiO2 made the compounds of Eu3+ disperse better and diminished the effect of concentration quenching. UV-Vis spectra and n&k analysis showed that the hybrid thin films had good transparency in visible light. Besides, the refractive index of hybrid thin films could be effectively controlled through the different ratio of SiO2 to EuL3 x 2H2O. TGA and DSC analysis indicated that the temperature of pyrolysis and T(g) increased with the increase in the SiO2 content. The results of SEM, SCMS, and AFM also showed that the hybrid thin films which prepared from the poly-functional acrylate had a flatter surface than those obtained from the single functional acrylate.

6.
J Nanosci Nanotechnol ; 9(7): 4135-42, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19916420

RESUMO

In this study, two types of the polyimide-silica hybrid thin films, 6FDA-ODA/SiO2 (FS0-FS50) and PMDA-ODA/SiO2 (PS0-PS40), with different silica content were synthesized by using the sol-gel method. TGA analysis showed that the thermal decomposition temperatures (T(d)) of FS and PS hybrid films were in the range of 457-505 degrees C and 458-516 degrees C, respectively. The T(d) increased with increasing the silica content. The measurement of contact angle and FTIR indicated that the hydrophilic and hydrolytic abilities were significantly improved when the silica content increased. The contact angle of PS0-PS40 films was in the range of 80.3-51.8 degrees. UV-Vis spectra showed that the cutoff wavelength of prepared hybrid films could be tunable through the silica content. The n&k analysis showed that the refractive index (n) of FS and PS hybrid films were in the range of 1.60-1.49 and 1.76-1.59, respectively, which could be controlled by the silica content. The extinction coefficients (k) are almost zero in the wavelength range of 300-900 nm, indicating the prepared hybrid films have an excellent optical transparency in the UV and visible region. TEM images showed that the particle size of silica in the hybrid thin films could be effectively controlled under sufficient content of coupling agent. Moreover, the results of SEM and AFM showed that the ratios of average roughness to thickness for all the prepared hybrid films were under 1.6%. It demonstrated that the prepared polyimide-silica hybrid thin films have an excellent film formability and planarity.

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