CuPc Particles Research Articles

Preparation of PANI/CuPc/PDMS Composite Elastomer with High Dielectric Constant and Low Modulus Assisted by Electric Fields.

Dielectric elastomer is a kind of electronic electroactive polymer, which plays an important role in the application of soft robots and flexible electronics. In this study, an all-organic polyaniline/copper phthalocyanine/silicone rubber (PANI/CuPc/PDMS) dielectric composite with superior comprehensive properties was prepared by manipulating the arrangement of filler in a polymer matrix assisted by electric fields. Both CuPc particles and PANI particles can form network structures in the PDMS matrix by self-assembly under electric fields, which can enhance the dielectric properties of the composites at low filler content. The dielectric constant of the assembled PANI/CuPc/PDMS composites can reach up to 140 at 100 Hz when the content of CuPc and PANI particles is 4 wt% and 2.5 wt%, respectively. Moreover, the elastic modulus of the composites remains below 2 MPa, which is important for electro-deforming. The strain of assembled PANI/CuPc/PDMS three-phase composites at low electric field strength (2 kV/mm) can increase up to five times the composites with randomly dispersed particles, which makes this composite have potential application in the field of soft robots and flexible electronics.

Lignins and Lignin Derivatives as Dispersants for Copper Phthalocyanine Pigment Nanoparticles

Copper phthalocyanine (CuPc) is a widely used organic blue pigment with color brilliance, light fastness, and low cost. However, its poor dispersibility in aqueous solutions limits the water-borne application. Lignin’s hyperbranched polymer structure makes it a potential dispersant. In this study, lignin is functionalized with carboxylic acid (−COOH) and amine (−NH2) to enhance the interaction with aqueous solutions. Their applications as dispersants for CuPc in aqueous solutions are investigated together with commercially available alkali lignin, dealkali lignin, and lignosulfonate. The effectiveness of dispersion stability is evaluated by the suspension stability. Lignin-NH2 enhanced the suspension stability of CuPc to allow 94 wt % CuPc particles to remain suspended in water for 24 h compared to 24.4 wt % with no dispersant added. The mechanism of dispersion is revealed by the measurements of zeta potential and particle size, as well as the calculation of lignin adsorption amount on CuPc. Moreover, the lignins are applied to disperse CuPc in acrylic resin as a water-based paint application. With the aid of lignin-NH2 dispersant, CuPc enhances the tinting strength to 110.75% without altering the blue color through color difference measurements. Lignin-NH2 contributes to both better suspension stability and tinting strength than a commercially available dispersant dioctyl sodium sulfosuccinate (DOSS).

Dispersion of copper phthalocyanine pigment nanoparticles by eco-friendly ethoxylated cardanol in aqueous solution

Abstract The environmentally friendly surfactant ethoxylated cardanol (EC) was investigated for dispersing copper phthalocyanine (CuPc) pigment nanoparticles into aqueous solution. The stability of the dispersion was investigated using UV-Vis spectra. The particle size was measured by optical microscopy, transmission electron microscopy and dynamic light scattering. The surface of the nanoparticles was characterised by measurements of the zeta potential and wettability. The coating application was investigated by incorporating CuPc blue pigment into resin and inorganic filler, and the colour strength of the coating film was compared. The results show that the EC can effectively wet and disperse the CuPc particles. The stabilisation of the particles is achieved by a steric mechanism in which the hydrophobic chains of the surfactant are adsorbed onto the surfaces of the CuPc nanoparticles and the ethylene oxide chains are dispersed in the aqueous phase. At EC concentrations greater than 0.1%, the CuPc nanoparticles appear to deagglomerate. The colour strength of CuPc nanoparticles present as dispersed pigment in resin can be increased in the presence of the EC surfactant.

Sonophotocatalytic treatment of wastewater using simulated solar light-driven Bi2O3-ZnO nanophotocatalyst sensitized with copper phthalocyanine

Bi2O3–ZnO photocatalysts with various amounts of copper phthalocyanine (CuPc) as photosensitizer agent were synthesized and used as novel photocatalysts in sonophotocatalytic degradation of methyl orange (MO). The sonophotocatalytic degradation of MO under simulated solar light irradiation was compared with sole photocatalysis and sole sonolysis, and the results showed that the decomposition performance was in the following order: sonophotocatalysis (30 W ultrasonic power) > photocatalysis > sonophotocatalysis (60 W ultrasonic power) > sonolysis. Among CuPc-Bi2O3–ZnO sonophotocatalysts with different contents of CuPc from 0% to 2% wt., the sample with 2% wt. indicated the highest MO sonophotodegradation percent of 94.66%. The characterization properties of synthesized sonophotocatalysts were identified by XRD, FESEM/EDX, BET/BJH, FTIR, TEM, and UV–Vis DRS. The XRD patterns indicated that, with increasing the CuPc amount from 0% to 2% wt., the crystallite size of ZnO in studied photocatalysts decreased from 54 to 41 nm. However, FESEM analysis illustrated fine nanoparticles (15–25 nm) with agglomeration on the outer surface that are related to Bi2O3 and CuPc particles. UV–Vis DRS showed that the sample with 2% wt. of CuPc had the highest visible light absorption and the lowest bandgap energy of 2.63 eV. The highest surface area and the smallest pore size were observed in this sample as well. The reusability test exhibited the excellent stability of CuPc-Bi2O3–ZnO sonophotocatalyst within six consecutive runs with negligible (5%) fading in sonophotocatalytic performance. Scavenger tests indicated that OH radical was not the dominant reactive specie, and sonication via physical aspects and production of other radicals influenced the photocatalytic reaction.

The 3D printing of dielectric elastomer films assisted by electrostatic force

Compared with traditional methods for preparing dielectric elastomer (DE) films, electrohydrodynamic (EHD) 3D printing displays many advantages, notably full automation, computer control and flexible design. It also confers high printing resolution, high preparation efficiency with minimal probability of nozzle clogging. In this article, EHD 3D printing was employed to fabricate silicone rubber (SR) based DE films. In order to increase their dielectric constant, high dielectric copper phthalocyanine (CuPc) particles were added into the SR ink. Optimal printing conditions were determined by analyzing the effects of printing voltage and ink properties on the formation of liquid cone and the printed line width. The SR/CuPc composite film with 3 wt% CuPc particles (SR/CuPc-3) exhibits a high dielectric constant of 5.52, with a large actuated area strain of 23.7% under an electric field of 39.4 V μm−1. Furthermore, under 100 cycles of electric field loading, SR/CuPc-3 demonstrate excellent electromechanical stability, indicating that EHD 3D printing holds a considerable potential for fabricating high-performance DE films in an efficacious manner.

Preparation of copper phthalocyanine/SiO2 composite particles through simple, green one-pot wet ball milling in the absence of organic dispersants.

In order to improve the dispersibility, thermal stability and pH adaptability of organic pigments in water, submicrometer copper phthalocyanine (CuPc)/SiO2 composite particles (CPs) were prepared through a simple one-pot wet ball-milling process under acidic conditions without using any organic surfactant. In the as-obtained CPs, the surface of the CuPc particles was homogeneously decorated with SiO2 nanoparticles (NPs) through hydrogen bonding interactions. Due to the surface-attached SiO2 NPs, the CuPc/SiO2 CPs present a high aqueous dispersibility and a pH-dependent colloidal stability. Furthermore, both the thermal stability and color intensity of CuPc were increased by encapsulation of CuPc particles within SiO2 NPs.

An approach to developing high dielectric constant nanocomposites based on polyrotaxane derivative

Polyrotaxane as a kind of supramolecular material has attracted more and more attention from researchers. Owing to the special topological interlocked structure, many properties and potential applications have been discovered. In this paper, a new polyrotaxane derivative has been synthesized based on the polyrotaxane end capped by 2,4-dinitrofluorobenzene (DNFB). And through cross-linking the polyrotaxane derivative meanwhile grafting copper phthalocyanine oligomer (CuPc) onto the side chains, high dielectric constant elastomeric nanocomposite was fabricated. TEM image showed the size of most CuPc particles is in the range of 10–20nm and the particles were dispersed uniformly in the matrix. According to the results of thermal analysis, compared to the pure cross-linking matrix the thermal stability of composites was obviously improved with the existence of CuPc fillers. At 100Hz, the dielectric constant of composite with 8wt% CuPc reaches to 135 and the dielectric loss is just 0.34 at room temperature.

Approach to the fabrication of acrylic elastomer nanocomposites with high dielectric constants

ABSTRACTDielectric elastomers (DEs) are a type of electroactive polymer that can deform in an electric field. The possession of a high dielectric constant is critical for DEs if they are to be suitable materials for the application of actuators. A novel elastomeric nanocomposite (ACE‐g‐CuPc) was fabricated by copper phthalocyanine oligomer (CuPc) grafting directly onto an acrylic elastomer (ACE) backbone. Compared with other synthetic methods, esterification has several advantages; these include fewer impurities and a simpler synthetic route. Transmission electron microscopy showed that the size of the CuPc particles of the ACE‐g‐CuPc was in the range 15–30 nm; this range was significantly smaller than that of ACE/CuPc (500 nm). The results of thermogravimetric analysis show that the thermal stability of the grafting composite was higher than that of the blending composite. At 100 Hz, the dielectric constant of the grafting composite (with 11 wt % CuPc) reached 173 at room temperature. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43904.

All‐organic nanocomposites of functionalized polyurethane with enhanced dielectric and electroactive strain behavior

For a dielectric elastomer, increasing its dielectric constant substantially could lead to a high electric field induced strain under a low operation field. In this work, high dielectric constant nanocomposites were developed by chemically bonding copper phthalocyanine oligomer (CuPc), a high dielectric constant organic semiconductor, to polyurethane (PU). Transmission electron microscope‐observed morphologies revealed that the sizes of CuPc particles in a nanocomposite of PU attached with 8.78 vol.% of CuPc were in the range of 10–20 nm, much smaller than the sizes (250–600 nm) in physical blend of PU with the same volume fraction of CuPc. At 100 Hz, the nanocomposite film exhibited a dielectric constant of 391, representing a more than 60 times increase with respect to the neat PU. The enhanced dielectric response in the nanocomposite makes it possible to induce a high electromechanical response. A strain of 17.7% and an elastic energy density of 0.927 J/cm3 were achieved under an electric field of 10 V/µm. Copyright © 2014 John Wiley & Sons, Ltd.

A polyurethane-based elastomeric nanocomposite with a high dielectric constant

To increase the electric energy density of dielectric elastomer substantially, high dielectric constant nanocomposites were developed using polyurethane (PU) as matrix and copper phthalocyanine oligomer (CuPc)—a high dielectric constant organic semiconductor—as filler. Transmission electron microscope (TEM)-observed morphologies revealed that the sizes of CuPc particles in nanocomposite of PU chemically attached with 8.78 vol% of CuPc were in the range of 10–20 nm, much smaller than the sizes (250–600 nm) in the physical blend of PU with the same volume fraction of CuPc. At 100 Hz, the nanocomposite film exhibited a dielectric constant of 391, representing more than 60-fold increase with respect to the pure PU. The enhanced dielectric response of the nanocomposite makes it possible to induce a high electromechanical response under a much reduced electric field (a strain of 17.7 % was achieved under a field of 10 V/μm).

Adsorption of Myrj 45 on copper phthalocyanine pigment nanoparticles and effect on their dispersion stability in aqueous solution

The composition of a commercial nonionic surfactant, Myrj 45, was analyzed with mass spectrometry (MS). Six classes of components, which are polyglycols, monoesters (monostearates and monopalmitates), and diesters (distearates, dipalmitates, and mixed diesters which are the diesters with stearoyl residues at one end and palmitoyl residues at the other) were detected. Each class of components shows a wide distribution of homologues. The monoesters are the dominant components in Myrj 45. The adsorption isotherm of each class of components was obtained using HPLC with a MS detector. The adsorption densities increase with increasing concentrations of each class of components up to a plateau. The monoesters adsorb the most at the same total surfactant concentration. The diesters and polyglycols also adsorb, but to a minor extent. The overall adsorption densities of Myrj 45 by taking into account the contributions from these six classes of components, are much lower than those of Triton X-100 at the same total molar concentration. The effect of Myrj 45 on the dispersion stability of the CuPc particles in pure water was studied and compared to that of Triton X-100. Upon adsorption of Myrj 45, the CuPc particles become quite hydrophilic, dispersible, and colloidally stable. Freezing/thawing and heating/cooling cycles tests suggest that the dispersions of CuPc particles with adsorbed Myrj 45 are not as stable as those with adsorbed Triton X-100. Particle aggregation primarily occurred during the freezing/thawing process. The experimental Fuchs–Smoluchowski dispersion stability ratios W exp of CuPc particles in surfactant solutions were determined from dynamic light scattering (DLS) data, for the Rayleigh–Debye–Gans (RDG) light scattering regime. The W exp-values with Myrj 45 are found to be about one order of magnitude smaller than those with Triton X-100. The zeta potentials are substantial, in the range of −16 to −46 mV, while the resulting surface charge densities and the total particle charges are quite low. Hence, electrostatic interactions are unlikely to contribute to the dispersion stabilization mechanism, which appears to be primarily steric.

Enhanced Dielectric Response in Polyurethane Based All-Organic Nanocomposite

A high dielectric constant nano-composite was fabricated using polyurethane (PU) as matrix and poly (p-chloromethyl styrene) (PCMS) grafted with copper phthalocyanine oligomer (CuPc, a planar multiring semiconductor with dielectric constant>105) (name the grafting product as PCMS-g-CuPc) as filler. According to the TEM-observed morphologies, PCMS-g-CuPc balls (~80 nm) distribute uniformly in PU matrix, while in PCMS-g-CuPc balls the PCMS acts as “matrix” which contains dispersed CuPc particles with a average size of ca. 25nm [1/20 of that of CuPc in simple blend of PU and CuPc (PU/CuPc)]. At 100Hz, the dielectric constant of the nanocomposite reaches 345, almost 7 times higher than that of PU/CuPc. The enhanced dielectric response in the nano-composite can be explained by the remarkably strengthened interface exchange coupling effect as well as the Maxwell-Wagner-Sillars polarization mechanism due to the significantly reduced CuPc particle size in the nano-composite.

Computational and Experimental Study of Colloidal Stability of CuPc Aqueous Dispersions

Dispersions of copper phthalocyanine (CuPc) pigments are commonly used in digital printing. Their colloidal stability is essential for fulfilling desirable shelf life and achieving good printing performance. In order to understand the role of electrostatic and van der Waals forces in their stability, a combined computational and experimental study has been performed to investigate the stability of the CuPc aqueous dispersions.The Hamaker constant was calculated with a novel combination of an ab initio and an empirical methodology (J. Chem. Theory Comput., 2010, 6 (2), pp 491–498) to address the van der Waals attractions between the pigment particles. The calculated Hamaker constant was then employed in the DLVO (Derjaguin-Landau-Verwey-Overbeek) equation for dispersion stability simulation. The predictions allow comparisons with experimental colloidal stability study of CuPc aqueous dispersions (Langmuir, 2010, 26 (10), pp 6995–7006)). The effect of a nonionic surfactant on the dispersion stability of CuPc particles was taken into consideration. The experimental dispersion stability ratio (W) was determined from dynamic light scattering (DLS) data and based on the Rayleigh-Debye-Gans (RDG) scattering theory. The adsorption isotherms show that the adsorption density increases with increasing equilibrium concentration of surfactant up to the cmc, and then reaches a plateau. Desorption tests were conducted to determine the reversibility or irreversibility of adsorption. Preliminary results suggest that a portion of the surfactant adsorbs irreversibly. The comparisons reveal that electrostatic forces play a significant role in the dispersion stabilization.

Colloidal Dispersion Stability of CuPc Aqueous Dispersions and Comparisons to Predictions of the DLVO Theory for Spheres and Parallel Face-to-Face Cubes

The dispersion stability and the zeta potentials of nonspherical crystalline (beta-form) copper phthalocyanine (CuPc) particles of hydrodynamic diameter d(h) approximately = 90 nm were investigated at 25 degrees C in water and in aqueous solutions of NaNO(3). The electrolyte concentrations c ranged from 1 to 500 mM and the particle concentrations ranged from 50 to 10,000 ppm (0.005 to 1 wt %). In each case, the Fuchs-Smoluchowski stability ratio W was determined from dynamic light scattering (DLS) data and the Rayleigh-Debye-Gans (RDG) scattering theory. The data suggest that electrostatic effects play a major role in the stability of CuPc-based dispersions. The calculated particle charge z per CuPc particle based on the zeta potential data and the area of the particles (assumed to be cubical) suggests that there is preferential adsorption of NO(3)(-) ions on the uncharged CuPc surface, and the surface charge increases with increasing electrolyte concentration. Furthermore, two new models of the DLVO theory, for spheres and for parallel face-to-face cubes, were reformulated in dimensionless form. The Hamaker constant of CuPc particles was calculated by the same authors on the basis of theoretical models in J. Chem. Theory Comput. (2010, in press). The key dimensionless group is the ratio N of the electrostatic double layer energy to the Hamaker constant. The two DLVO models were used to predict the value of a dimensionless maximum potential energy Phi(max), the conditions when it may exist, and then the value of W. In water, the DLVO model for spheres overpredicted the stability, while the model for cubes underpredicted the stability. At c = 1 mM, both models overpredicted the stability. At c = 10 mM, the model for spheres underpredicted the stability, whereas the model for cubes overpredicted the stability. Hence, there seems to be some significant shape effects on the electrostatic stabilization of CuPc particle dispersions. At c = 100 and 500 mM, both models underpredicted the stability substantially, suggesting the existence of additional short-range repulsive forces, which may primarily control the stability. Simple sensitivity analysis on the calculations supported these conclusions.

Enhanced dielectric response in P(VDF-TrFE) based all-organic nanocomposites

A nanocomposite with enhanced dielectric response is developed using poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] as matrix and Chemically modified high dielectric constant organic semiconductor—copper phthalocyanine oligomer (CuPc)—as filler. Transmission electron microscope (TEM)-observed morphologies reveal that in the nanocomposite the average size of CuPc particles is about 25 nm [1/24 of that of CuPc in physical blend of P(VDF-TrFE) and CuPc]. The hot-press nanocomposite film with 15 wt % CuPc can realize a dielectric constant of 540 at 100 Hz. The enhanced dielectric response in the nanocomposite demonstrates the significance of the interface effect in raising the material responses far beyond that expected by simple mixing rules when there is a large dielectric contrast between the polymer matrix and the dielectric filler in the composite. It is also interesting to note that at high frequencies (such as 100 MHz) the nanocomposite has a dielectric constant of ∼100 and this value is comparable to those of current materials used in microwave applications. At 105 °C that is near the ferroelectric-to-paraelectric phase transition temperature of the P(VDF-TrFE) ferroelectric, a much higher dielectric constant (about 1200 at 100 Hz) is obtained. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 490–495, 2010

Exchange coupling in P(VDF-TrFE) copolymer based all-organic composites with giant electrostriction.

In this Letter, we discuss the dramatically enhanced electrostriction and dielectric constant in an all-organic composite consisting of polyvinylidene fluoride trifluoroethylene [P(VDF-TrFE)] copolymer matrix and copper-phthalocyanine (CuPc) particles, which could not be explained by traditional composite theory. Using a Landau-type potential energy combined with energy minimization, we demonstrate that the dramatic property enhancement is due to the exchange coupling between the dielectrically hard P(VDF-TrFE) and dielectrically soft CuPc, which becomes dominant when the heterogeneity size of the composite is comparable to the exchange length. The exchange coupling is a very effective mechanism for the enhancement of functional properties in ferroelectric and dielectric systems, and its variation with various material parameters is demonstrated and discussed.

Liquid Toner Charging Mechanisms: Electrophoretic Mobilities of Copper Phthalocyanine Pigment Dispersions

Electrophoretic mobilities of copper phthalocyanine (CuPc) particles dispersed in Isopar G™ are reported. The mobilities were measured as a function of particle charging agent (PCA) concentration using Phase Analysis Light Scattering (PALS). The role of Particle Stabilizing Agents (PSAs) at the particle surface was also investigated. An equilibrium site binding model can describe the experimental data adequately. Conductivity measurements and adsorption isotherms facilitate an overall description of particle charging in these systems.

Nature of the improved Raman scattering from α-copper phthalocyanine particles on a compacted electrode

Electrodes consisting of a compacted mixture of powders of silver metal and α-copper phthalocyanine (CuPc) have been used to study small pigment particles bonded to the metal surface using resonance Raman spectroscopy as a probe of in situ changes. This system provides a different starting point for the study of the nature of the terms which give rise to improved Raman scattering at metal surfaces. An understanding of these processes is vital if Raman spectroscopy is to achieve its potential as an in situ method for the detection of reactions at metal/organic interfaces in aqueous solution. Resonance excitation profiles (REPs) indicate that the improved scattering is in the region of the phthalocyanine absorption (Q band) and resembles a CuPc multilayer. There is a significant electronic interaction between the particles and the metal surface with a downward shift in the 0–0 transition energy of the Q band of ca. 30 nm. The REPs from the electrode surface are more clearly resolved than for CuPc itself. There are fewer effective vibronic contributions especially at negative potentials and scattering is greater from higher vibronic levels. New bands not present in the spectrum of CuPc appear at negative potentials and the appearance coincides with changes in intensity of bands observed at all potentials. Two different mechanisms of enhancement are indicated: a resonance mechanism where increased scattering efficiency is achieved both by good sample presentation and by an electronic interaction between the particles and the metal, and a surface-enhanced resonance effect which competes with the resonance mechanism at negative potentials. Both the resonance effect and the surface-enhanced effect give rise to REPs attributable to phthalocyanine Q-band interactions. Both processes arise from a long-range ‘charge-transfer’ mechanisms between the CuPc particles and the metal rather than from short-range metal–monolayer interactions.

Formation of Copper Phthalocyanine Thin Films by Electrolysis of Surfactants with Ferrocenyl Moiety

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Particle–metal interactions. A raman and electrochemical study of a compacted electrode of copper phthalocyanine and silver metal

Electrodes consisting of a compacted mixture of powders of silver metal and α copper phthalocyanine (CuPc) have been used to study the interaction between small pigment particles and a metal surface using resonance Raman spectroscopy as a probe of in situ changes. The purpose of this present paper is to explore the condition required to produce optimum enhancement.Cycling in acid sulphate or nitrate electrolytes with a sufficiently positive voltage to release silver(I) ions resulted in the formation of a thin layer of CuPc particles spread out on the metal surface. The layer formed produced an improvement in Raman scattering from CuPc. From the resonance profile it was clear that there was a significant charge transfer interaction with the metal surface. The relative intensities of the peaks in the Raman spectra are dependent on potential. As well as the possible use of such electrodes in chemistry, particle metal layers of this type provide a different starting point for studies of the surface enhanced resonance Raman effect emphasising the electromagnetic contribution rather than the chemical one.