Transparent poly(methyl methacrylate‐co‐butyl acrylate) nanofibers

Nanofibers of n‐Butyl Acrylate/Methyl Methacrylate copolymer [P(BA‐co‐MMA)] were produced by electrospinning in this study. P(BA‐co‐MMA) was synthesized by emulsion polymerization. The structural and thermal properties of copolymers and electrospun P(BA‐co‐MMA) nanofibers were analyzed using Fourier transform infrared spectroscopy–Attenuated total reflectance (FTIR–ATR), Nuclear magnetic spectroscopy (NMR), and Differential scanning calorimetry (DSC). FTIR–ATR spectra and NMR spectrum revealed that BA and MMA had effectively participated in polymerization. The morphology of the resulting nanofibers was investigated by scanning electron microscopy, indicating that the diameters of P(BA‐co‐MMA) nanofibers were strongly dependent on the polymer solution dielectric constant, and concentration of solution and flow rate. Homogeneous electrospun P(BA‐co‐MMA) fibers as small as 390 ± 30 nm were successfully produced. The dielectric properties of polymer solution strongly affected the diameter and morphology of electrospun polymer fibers. The bending instability of the electrospinning jet increased with higher dielectric constant. The charges inside the polymer jet tended to repel each other so as to stretch and reduce the diameter of the polymer fibers by the presence of high dielectric environment of the solvent. The extent to which the choice of solvent affects the nanofiber characteristics were well illustrated in the electrospinning of [P(BA‐co‐MMA)] from solvents and mixed solvents. Nanofiber mats showed relatively high hydrophobicity with intrinsic water contact angle up to 120°. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4264–4272, 2013     

Complexation of poly(dimethylsiloxane)/poly(methyl methacrylate‐co‐butyl acrylate‐co‐methacrylic acid) latex with poly(dimethylsiloxane)/poly(vinyl acetate‐co‐butyl acrylate) latex

Two latices—the poly(dimethylsiloxane) (PDMS)/poly(methyl methacrylate‐co‐butyl acrylate‐co‐methacrylic acid) system (PA latex) and the PDMS/poly(vinyl acetate‐co‐butyl acrylate) system (PB latex)—were prepared by seeded emulsion polymerization, and PA/PB complex latices were obtained through the interparticle complexation of the PA latex with the PB latex. In addition, for the further study of the interparticle complexation of the PA latex with the PB latex, copolymer latices [PDMS/methyl methacrylate‐co‐butyl acrylate‐co‐vinyl acetate‐co‐methacrylic acid) (PC)] were prepared according to the monomer recipe of the complex latices and the polymerization process of the component latices. The properties of the obtained polymer latices and complex latices were investigated with surface‐tension, contact‐angle, and viscosity measurements. The mechanical properties of the coatings obtained from the latices were investigated with tensile‐strength measurements. The results showed that, in comparison with the two component latices (PA latex and PB latex) and the corresponding copolymer latices (PC latices), the PA/PB complex latices had lower surface tension, lower viscosities, and better wettability to different substrates. The tensile strengths of the coatings obtained from the complex latices were higher than the tensile strengths of the coatings from the two component latices and copolymer latices. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2522–2527, 2004     

Effect of temperature on the optical and electro-optical properties of poly(methyl methacrylate)/E7 polymer-dispersed liquid crystal composites

Experiments on the effect of temperature on the optical and electro-optical behaviors of polymer-dispersed liquid crystals (PDLCs) are considered. Composite films composed of poly(methyl methacrylate) (PMMA) and the nematic-type liquid crystal (LC) E7 were prepared by solvent casting in chloroform. The PDLC film contained droplets of E7 from 10 to 80 wt % in a PMMA matrix. Morphological studies illustrated the formation of isolated droplets of LC due to phase separation, and their homogeneous distribution increased with increasing E7 content. Thermo-optical studies showed an increase in the nematic–isotropic transition temperature of composites, which indicated preferential solvation during the phase-separation process. The electro-optical characteristics were studied under the conditions of an externally applied square wave electric field with a He–Ne laser (λ = 632.8 nm) as a light source. The responses improved as the E7 content in PMMA increased. Semipermanent memory effects were noticed in composites at higher temperatures. Changes in the transmittance due to thermal variations provided the possibility of using such a device as a temperature sensor. The results obtained indicate that under these experimental conditions, the output can be controlled to the desired level by the selection of a suitable loading of LC to prepare PDLC electro-optically active composite films with a response time on the order of only a few milliseconds. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation of hemispherical poly(4‐vinylpyridine‐co‐butyl acrylate)/poly(styrene‐co‐butyl acrylate) composite microspheres by seeded preswelling emulsion polymerization

Seeded preswelling emulsion polymerization was carried out by using monodispersed poly(4‐vinylpyridine‐co‐butyl acrylate) [P(4VP‐BA)] particles as the seed, and styrene and butyl acrylate as the second‐stage monomers under different polymerization conditions, to obtain hemispherical polystyrene (PST)‐rich–P4VP‐rich microspheres. Prior to polymerization, toluene was added into the preswelling system together with the second‐stage monomers. It was found that, with the increase of the amount of toluene, the particle morphology showed a tendency toward desirable hemispherical structure, and the colloidal stability of composite latex was improved. When the weight ratio of toluene/seed latex was increased up to 7.5/40 (g/g), the stable hemispherical latex could be obtained. However, when toluene was not added, the coagulum formed on the wall of the reactor during polymerization, and the composite particles with multiple surface domains (such as sandwich‐like, popcorn‐like) were formed. In addition, the final morphology of composite particles was influenced by the polarity of the seed crosslinker and the hydrophilicity of the second‐stage initiator, which could affect the mobility of poly(styrene‐co‐butyl acrylate) [P(ST‐BA)] chains. The morphology development during the polymerization was investigated in detail, and a schematic model was derived to depict the formation mechanism of hemispherical P(4VP‐BA)/P(ST‐BA) composite microspheres. The results revealed that the mobility of the P(ST‐BA) chains influenced the diffusion of the P(ST‐BA) domains on the surface of the P(4VP‐BA) matrix. When the mobility of the P(ST‐BA) chains allowed small‐size P(ST‐BA) domains to coalesce into one larger domain, complete phase‐separated morphology (hemisphere) could be achieved. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3811–3821, 2003     

Electro–optic studies on polymer‐dispersed liquid crystal composite films. I. Composites of PVB–E7

The electro‐optic performance characteristic of polymer‐dispersed liquid crystal (PDLC) composite films out of poly(vinyl butyral) (PVB) and nematic liquid crystal (E7) have been studied for a wide range of PVB–E7 composite compositions (20–70 wt % of E7). Composites were prepared by solvent casting from chloroform at room temperature. A scanning electron microscopy study showed that a E7 phase is continuously embedded in chink‐like structure of PVB matrix. Optical transmittance of the composite films (of 60 and 70 wt % loading of E7) under an alternating current (ac) electric field (0–250, V_p‐p) and frequency (50 Hz to 1 KHz) were measured employing He Ne laser (λ = 632.8 nm). The results indicate that the (PVB–E7) composite exhibits a memory effect. In the memory state, higher transmittance is preserved without applying voltage. The memory state can be erased and changed to the scattering Off‐state by heating the film to the clearing temperature of the liquid crystal. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3485–3491, 1999     

Preparation of silica/poly(styrene‐co‐butyl acrylate) core/shell composite particles for absorption of toluene

An absorbent for benzene series with silica/poly(styrene‐co‐butyl acrylate) core/shell structure was prepared via emulsion polymerization. The effects of emulsifier dosage, monomer concentration, and crosslinker dosage on the absorption of the core/shell composite particles were investigated. The composite particles with good absorbency could be obtained when the emulsifier concentration was 2.5 g/L, monomer concentration was 40 g/L, crosslinker dosage was 2.0% (based on the total mass of the monomer), and the initiator dosage was 1.0%. The composite particles exhibited a rapid absorption and the absorption process conformed to the quasi‐second order kinetics. Fourier‐transform infrared spectroscopy, scanning electron microscope, and energy dispersive spectrometer (EDS) showed the presence of copolymer layer on the surface of silica. The work provided a new path to fabricate novel composite absorbent particles for a wide range of applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46172.     

Dynamic mechanical properties of semi‐interpenetrating polymer network‐based on nitrile rubber and poly(methyl methacrylate‐co‐butyl acrylate)

In this article, semi‐interpenetrating polymer network (Semi‐IPNs) based on nitrile rubber (NBR) and poly(methyl methacrylate‐co‐butyl acrylate) (P(MMA‐BA)) were synthesized. The structure and damping properties of the prepared Semi‐IPNs blends were characterized and by fourier transform infrared spectrum (FTIR), dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), thermogravimetric analysis (TGA/DTG), and tensile mechanical properties. The results showed that interpenetrating network based on P(MMA‐BA) and NBR was successfully obtained, which showed the improved thermal stability compared to NBR/P(MMA‐BA)‐based two‐roll mill blends. Furthermore, Semi‐IPNs showed significantly better the dynamic mechanical properties than that of the two‐roll mill system. With the increasing feed ratio of BA and MMA during the preparation of Semi‐IPNs, the loss peak position for P(MMA‐BA) in NBR/PMMA IPNs shifted to a lower temperature from 20°C to ?17°C, and when NBR in Semi‐IPNs was accounted for 40 wt %, the dynamic mechanical thermal analysis showed that much more advanced damping material with wider temperature range (?30°C < T < 80°C) as tan δ > 0.45 can be achieved. Therefore, it was expected as a promising way to obtain the excellent damping materials with good oil‐resisted properties according the Semi‐IPNs system. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40217.     

Preparation of poly(methyl methacrylate‐co‐butyl methacrylate) nanoparticles and their reinforcing effect on natural rubber

Poly(methyl methacrylate‐co‐butyl methacrylate) [P(MMA‐co‐BMA)] nanoparticles were synthesized via emulsion polymerization, and incorporated into natural rubber (NR) by latex compounding. Monodispersed, core‐shell P(MMA‐co‐BMA)/casein nanoparticles (abbreviated as PMBMA‐CA) were produced with casein (CA) as surfactant. The chemical structure of P(MMA‐co‐BMA) copolymers were confirmed by ¹H‐NMR and FTIR analyses. Transmission electron microscopy demonstrated the core–shell structure of PMBMA‐CA, and PMBMA‐CA homogenously distributed around NR particles, indicating the interaction between PMBMA‐CA and NR. As a result, the tensile strength and modulus of NR/PMBMA‐CA films were significantly enhanced. The tensile strength was increased by 100% with 10% copolymer addition, when the molar ratio of MMA:BMA was 8:2. In addition, scanning electron microscopy and atomic force microscopy results presented that the NR/PMBMA‐CA films exhibited smooth surfaces with low roughness, and PMBMA‐CA was compatible with NR. FTIR‐ATR analyses also suggested fewer PMBMA‐CA nanoparticles migrated out of NR. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43843.     

Poly(styrene‐co‐butyl acrylate) latex‐reinforced polyester nonwoven fabric composites: Thermal and morphological studies

A series of thermoplastic composites were fabricated by impregnating the polyester nonwoven fabric in poly(styrene‐co‐butyl acrylate) latex having different monomer compositions of styrene and butyl acrylate viz., 100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 weight by weight. Thermogravimetric analysis (TGA) of the composites was performed to establish the thermal stability and their mode of thermal degradation. From TGA thermograms, a slight improvement in thermal stability of the composites was noticed compared to polyester nonwoven fabric. Degradation kinetic parameters were obtained for the composites using Broido and Coats–Redfern methods. The activation energy (E_a) of the composites for the thermal degradation process lies in the range 7.1–261 and 60–264 kJ/mol for Broido and Coats–Redfern methods respectively. Morphology of the tensile‐fractured composites was studied using scanning electron microscopic technique. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Study on synthesis and morphology control of poly(4‐vinylpyridine‐co‐butyl acrylate)/poly(styrene‐co‐butyl acrylate) composite microspheres

Monodispersed crosslinked cationic poly(4‐vinylpyridine‐co‐butyl acrylate) [P(4VP‐BA)] seed latexes were prepared by soapless emulsion polymerization, using 2,2′‐azobismethyl(propionamidine)dihydrochloride (V₅₀) as an initiator and divinylbenzene (DVB) or ethylene glycol dimethacrylate (EGDMA) as a crosslinker. The optimum condition to obtain monodispersed stable latex was investigated. It was found that the colloidal stability of the P4VP latex can be improved by adding an adequate amount of BA (BA/4VP = 1/4, w/w), and adopting a semicontinuous monomer feed mode. Subsequently, poly(4‐vinylpyridine‐co‐butyl acrylate)/Poly(styrene‐co‐butyl acrylate) [P(4VP‐BA)/P(ST‐BA)] composite microspheres were synthesized by seeded polymerization, using the above latex as a seed and a mixture of ST and BA as the second‐stage monomers. The effects of the type of crosslinker, the degree of crosslinking, and the initiators (AIBN and V₅₀) on the morphology of final composite particles are discussed in detail. It was found that P(4VP‐BA)/P(ST‐BA) composite microspheres were always surrounded by a PST‐rich shell when V₅₀ was used as initiator, while sandwich‐like or popcorn‐like composite particles were produced when AIBN was employed. This is because the polarity of the polymer chains with AIBN fragments is lower than for the polymer with V₅₀ fragments, hence leading to higher interfacial tension between the second‐stage PST‐rich polymer and the aqueous phase, and between PST‐rich polymer and P4VP‐rich seed polymer. As a result, the seed cannot be engulfed by the PST‐rich polymer. Furthermore, the decrease of T_g of the second‐stage polymer promoted phase separation between the seeds and the PST‐rich polymer: sandwich‐like particles formed more preferably than popcorn‐like particles. It is important knowledge that various morphologies different from PST‐rich core/P4VP‐rich shell morphology, can be obtained only by changing the initiator, considering P4VP is much more hydrophilic than PST. The zeta potential of composite particles initiated by AIBN in seeded polymerization shifted from a positive to a negative charge. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1190–1203, 2002     

Poly(methyl acrylate)/Na‐montmorillonite intercalated composites: Preparation and characterization

Poly(methyl acrylate)/Na‐montmorillonite intercalated composites were prepared by free‐radical polymerization using benzoyl peroxide as a radical initiator in an aqueous medium. XRD patterns confirmed that the increase in interlayer spacing of Na‐montmorillonite (Na‐MMT) from 1.21 to 1.64 nm supports the intercalation. Although the width of the intercalated, delaminated montmorillonite aggregates are less than 100 nm (as seen in transmission electron microscopy), the prepared samples are members of the intercalated composite group. The samples exhibited better thermal stability than the pure polymer. Nitrogen adsorption capacity decreased due to the hindering of molecule diffusion and shielding of the intercalated aggregates by the polymer matrix. The decrease in moisture and water uptake of the samples indicated that the hydrophilic nature of montmorillonite changed greatly due to the hydrophobicity with increasing polymer content. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of a chiral dopant on the electro‐optical properties of polymer‐dispersed liquid‐crystal films

Polymer‐dispersed liquid crystal (PDLC) films were prepared by the ultraviolet‐light‐induced polymerization of photopolymerizable monomers in nematic liquid crystal/monomer/chiral dopant composites, and the effect of the chiral dopant on the electro‐optical properties of the PDLC films was studied. It was demonstrated that the addition of a small amount of the chiral dopant increased the driving voltage somewhat but decreased the turn‐off time significantly. Furthermore, the transmittance of ultraviolet, visible, and near‐infrared light of the off state of PDLC films showing light scattering increased with increasing content of the chiral dopant, and the optimum electro‐optical properties of the PDLC films were obtained when the content of the chiral dopant was not more than 2 wt %. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Film formation from pigmented latex systems: Drying kinetics and bulk morphologies of ground calcium carbonate/functionalized poly(n‐butyl methacrylate‐co‐n‐butyl acrylate) blend films

The drying kinetics and bulk morphology of pigmented latex films obtained from poly(n‐butyl methacrylate‐co‐n‐butyl acrylate) latex particles functionalized with carboxyl groups and ground calcium carbonate blends were studied. Latex/pigment blends with higher carboxyl group coverage on the latex particle surfaces dried faster than films with few or no carboxyl groups present. The latex/pigment dispersions also dried faster when there was more stabilizer present in the blend system because of the hydrophilic nature of the stabilizer. The net effect of increasing the pigment volume concentration in the blend system was to shorten the drying time. The bulk morphologies of the freeze‐fractured surfaces of the pigmented latex films were studied with scanning electron microscopy. Scanning electron microscopy analysis showed that increased surface coverage of carboxyl groups on the latex particles in the latex/pigment blends resulted in the formation of smaller pigment aggregates with a more uniform size distribution in the blend films. In addition, the use of smaller latex particles in the blends reduced the ground calcium carbonate pigment aggregate size in the resulting films. Scanning electron microscopy analysis also showed that when the initial stabilizer coverage on the latex particles was equal to 18%, smaller aggregates of ground calcium carbonate were distributed within the copolymer matrix of the blend films in comparison with the cases for which the initial stabilizer coverage on the latex particles was 8 or 36%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2267–2277, 2006     

Optical switching behavior of polymer‐dispersed liquid crystal composite films with various novel azobenzene derivatives

Polymer‐dispersed liquid crystal (PDLC) composite films were fabricated by thermal polymerization with E7 liquid crystal, monomers, and novel azobenzene derivatives synthesized in this study. To investigate the effects of azocompounds on the optical switching of PDLC films, a series of novel azobenzene derivatives of 4‐alkyloxy‐4′‐methoxyazobenzene with carbon numbers of 3–6, chiral compounds of amyl‐4‐(4‐hexyloxyphenylazo)benzoate, and bornyl‐4‐(4‐hexyloxyphenylazo)benzoate were synthesized. The compounds synthesized in this investigation were identified using FTIR, NMR, and elemental analysis. The optical texture of the composite films was analyzed under crossed nicols with a polarizing microscope. The morphological observation of the solid polymer in the composite films was performed with a scanning electron microscope (SEM). The optical behavior of the composite films on UV irradiation and the effects of the curing time on the thermal stability of the composite films were investigated. Isomerization of the azobenzene derivatives due to UV irradiation was confirmed by a texture study and image recording method. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 789–799, 2004     

Structural effect of photoinitiators on electro‐optical properties of polymer‐dispersed liquid crystal composite films

Two types of photoinitiators were synthesized: (1) a α,ω‐telechelic oligomeric photoinitiator, by the reaction of poly(propylene glycol) diglycidylether (PPGDGE) and 2‐hydroxy‐2‐methyl‐1‐phenyl‐propan‐1‐one (Darocur 1173), and (2) a polymeric photoinitiator, by copolymerization of a monomer that had a liquid crystalline property, 4‐[ω‐(2‐methylpropenoyloxy)decanoxy]‐4′‐cyanobiphenyl, with a vinyl monomer that had a photosensitive group. For comparison, low‐molecular‐weight (low‐MW) photoinitiator (Darocur 1173) also was used. Attention was directed to the structural effect of the photoinitiators on the electro‐optical properties of polymer‐dispersed liquid crystal (PDLC) film in which the LC phase occupied a major volume (80 wt % of the composite film). For the preparation of PDLC films by the polymerization‐induced phase separation method, the optimum UV‐curing temperature was observed at 50°C, a temperature slightly higher than the cloud temperature (T_cloud) of the low‐MW LC/matrix‐forming material mixture. It was found that the electro‐optical performance of the PDLC cell fabricated with the oligomeric or polymeric photoinitiator was better than that of the PDLC cell made with a low‐MW photoinitiator (Darocur 1173), exhibiting lower driving voltage (V₉₀) and higher contrast ratio under identical formulation conditions. Oligomeric photoinitiators allowed premature phase separation between the LC and matrix phases, resulting in relatively pure LC‐rich phases. For the polymeric photoinitiator, incorporation of mesogenic moieties into the photoinitiator resulted in not only a well‐defined LC/matrix morphology but also in low driving voltage (V₉₀) because of reduced friction at the LC/matrix interfaces. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 162–169, 2006     

Ultrasound‐assisted emulsion polymerization of poly(methyl methacrylate‐co‐butyl acrylate): Effect of initiator content and temperature

In this study, we propose an efficient method for preparation of large scale, monodisperse poly(methyl methacrylate‐co‐butyl acrylate) latexes by application of the low power ultrasound irradiation. The effect of polymerization temperature and initiator concentration on the polymerization nature, particle size, and particle size distribution were investigated. Results indicated that the ultrasound pulses in the first minutes of polymerization increase instant free radical to monomer ratio as well mixing efficiency which led to higher monomer conversion, improved polymerization rate (especially at first 15 min of the reaction), and remarkable decrease in molecular weight distribution. Transmittance electron microscopy (TEM) and dynamic light scattering (DLS) revealed that the particle size and particle size distribution were significantly affected, particle size decreased, and more uniform particles were obtained. Dynamic mechanical thermal analysis also showed that the initiator concentration affected glass transition temperature (T_g) of the final copolymers and in the case of ultrasound‐assisted emulsion polymerization T_g was in a very good agreement with theoretical predictions for copolymerization. POLYM. ENG. SCI., 56:214–221, 2016. © 2015 Society of Plastics Engineers     

Synthesis and characterization of poly[methyl methacrylate‐co‐2‐ethylhexyl acrylate‐co‐poly(propylene glycol diacrylate)] latices

The emulsion polymerization of the monomers methyl methacrylate (MMA) and 2‐ethylhexyl acrylate (EHA) was studied to investigate the effect of the crosslinkable monomer poly(propylene glycol diacrylate) (PPGDA). IR spectroscopy, NMR, differential scanning calorimetry, gel permeation chromatography, and scanning electron microscopy were used to characterize the synthesized polymers. These polymers were coated on glass panels and cured at appropriate temperatures to study the physical properties, swelling behavior, surface tension, and contact angle of these polymer latices. The results show that as the concentration of EHA monomer increased, the surface tension of the latices decreased. The copolymers were characterized by ¹H‐NMR spectroscopy to ensure the absence of unreacted monomer, and the results confirm the incorporation of EHA units in the copolymer. The contact angle of the latices on the glass substrate was smaller than that on the metal. The swelling mechanism of the film showed that the Fickian diffusion coefficient with 10 wt % PPGDA was at a minimum value and was the most highly crosslinked polymer among the samples. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

In situ preparation and properties of high‐solid‐content and low‐viscosity poly(methyl methacrylate/n‐butyl acrylate/acrylic acid)/poly(styrene/acrylic acid) composite latexes

With monodispersed poly(methyl methacrylate/n‐butyl acrylate/acrylic acid) [P(MMA/BA/AA)] seeded latex with a particle size of 485 nm and a solid content of 50 wt % as a medium, a series of stable P(MMA/BA/AA)/poly(styrene/acrylic acid) composite latexes with a high solid content (70 wt %) and low viscosities (500–1000 mPa · s when the shear rate was 21 s^?1) was prepared in situ via simple two‐step semicontinuous monomer adding technology. The coagulum ratio of polymerization was about 0.05 wt %. The particle size distribution of such latexes was bimodal, in which the large particle was about 589 nm and the small one was about 80 nm. The latexes combined good mechanical properties with good film‐forming properties. Differential scanning calorimetry showed that the corresponding latex film had a two‐phase structure. The morphology of the latex film was characterized with atomic force microscopy and scanning electron microscopy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1815–1825, 2007     

Enhanced thermoelectric properties of poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate)/copper phthalocyanine disulfonic acid composite films

A series of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate)/copper phthalocyanine disulfonic acid (PEDOT: PSS/CuPc-[SO₃H]₂) composite films were prepared by using CuPc-(SO₃H)₂ as the dopant. EG treatment was applied to further improve the thermoelectric properties of PEDOT: PSS/CuPc-(SO₃H)₂ composites. Structural analyses indicated the strong π − π interactions existed between PEDOT: PSS and CuPc-(SO₃H)₂, and led to more ordered regions in the composite films, and benefit the conductivity. CuPc-(SO₃H)₂ can greatly improve the thermoelectric properties of PEDOT: PSS/CuPc-(SO₃H)₂ composite films, which have a Seebeck coefficient of 13.2 μV K⁻¹ and a conductivity of 2.8 × 10⁵ S/m with 20 wt% CuPc-(SO₃H)₂ at room temperature, and the corresponding power factor is 48.8 μW m⁻¹ K⁻², which is almost 6.83 times higher than the PEDOT: PSS films without CuPc-(SO₃H)₂.     

Preparation and properties of core–shell nanosilica/poly(methyl methacrylate–butyl acrylate–2,2,2‐trifluoroethyl methacrylate) latex

A core–shell nanosilica (nano‐SiO₂)/fluorinated acrylic copolymer latex, where nano‐SiO₂ served as the core and a copolymer of butyl acrylate, methyl methacrylate, and 2,2,2‐trifluoroethyl methacrylate (TFEMA) served as the shell, was synthesized in this study by seed emulsion polymerization. The compatibility between the core and shell was enhanced by the introduction of vinyl trimethoxysilane on the surface of nano‐SiO₂. The morphology and particle size of the nano‐SiO₂/poly(methyl methacrylate–butyl acrylate–2,2,2‐trifluoroethyl methacrylate) [P(MMA–BA–TFEMA)] core–shell latex were characterized by transmission electron microscopy. The properties and surface energy of films formed by the nano‐SiO₂/P(MMA–BA–TFEMA) latex were analyzed by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy/energy‐dispersive X‐ray spectroscopy, and static contact angle measurement. The analyzed results indicate that the nano‐SiO₂/P(MMA–BA–TFEMA) latex presented uniform spherical core–shell particles about 45 nm in diameter. Favorable characteristics in the latex film and the lowest surface energy were obtained with 30 wt % TFEMA; this was due to the optimal migration of fluorine to the surface during film formation. The mechanical properties of the films were significantly improved by 1.0–1.5 wt % modified nano‐SiO₂. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011