Polymerizable Cationic Surfactant Research Articles

A high temperature retarded acid based on self-assembly of hydrophobically associating polymer and surfactant

Development of the novel retarded acid using in high temperature acidizing and acid fracturing remains an important challenge. Terpolymer-hydrophobically associating polyacrylamide (HA-PAM) with more content of hydrophobic monomer than conventional water-soluble association polymers designed to use as acid thickener was synthesized through aqueous solution polymerization with polymerizable cationic surfactant. The polymer structure was characterized by FT-IR and 1H NMR. The viscous performances in 20 % hydrochloric acid aqueous solution of HA-PAMs synthesized with different amounts of cationic hydrophobic monomer were investigated. The effects of different concentrations of HA-PAM on the viscous performance were also investigated. To further increase the viscosity, a selected surfactant was added to the thickened acid formed by synthesized HA-PAM to form a physically associating acid through micelle and HA-PAM associating interaction. Thickening performance, viscoelasticity, shearing resistance and temperature resistance for physically associating acid was evaluated by Rheometer. The viscosity of physically associating acids formed by the synergy of designed acid thickening polymers and surfactant exceeded 50 mPa·s under 123 °C, which demonstrated the self-assembly acids meet the requirements for high temperature acid fracturing. The designed acid thickening polymers and novel self-assembly acids by physical association have potential applications in high temperature acidizing and acid fracturing.

Individually isolated single wall carbon nanotubes with controlled surface charge density

Individually isolated single wall carbon nanotubes (SWNTs) with controlled surface charge density in water have been developed. First, the polymerizable cationic surfactant, cetyltrimethylammonium 4-vinylbenzoate (CTVB), is self-assembled on the hydrophobic surface of SWNTs in the presence of different amount of polymerizable co-monomer, sodium 4-styrenesulfonate (NaSS). Second, the self-assembled CTVB/NaSS monolayer is permanently fixed by in situ polymerization, making individually isolated SWNT dispersion in water. The surface charge density of functionalized SWNTs is controlled by the amount of NaSS relative to that of CTVB. The zeta potential of the functionalized SWNTs is systematically varied from positive to negative (+12.3 ∼ −47.8 mV) as the concentration of NaSS is increased from 0 to 60 mol % relative to the CTVB concentration. The charge variation is understood in terms of an overcharging effect in the charged colloidal system. The small angle neutron scattering (SANS) measurements show that electrostatic interaction between the functionalized SWNTs is strongly dependent on the NaSS concentration, which is consistent with the zeta potential measurements. The SANS measurements also show that the thickness of polymerized CTVB/NaSS monolayer adsorbed on SWNTs is almost constant at 1.89 nm regardless of the NaSS concentration, and the microstructure and surface charge are well maintained at high temperature (60 °C) as well as even after harsh condition such as freeze-drying.

Facile fabrication of Sudan red particle microcapsules by a polymerizable gemini surfactant and molecular assembly mechanisms.

An efficient method was developed to encapsulate water insoluble organic particles of Sudan red III (SR) in aqueous suspensions by using a polymerizable cationic gemini surfactant, 1,3-bis(N,N-dimethyl-N-cetylammonium)-2-(propylacrylate dibromide) (AGC16). The AGC16 coated SR microcapsules (AGC16@SR) were prepared by absorption of AGC16 on the surface of SR, followed by in situ homopolymerization (PAGC16). Several measurements, including transmission and scanning electron microscopy, isothermal titration calorimetry, zeta potential, electron paramagnetic resonance and small angle X-ray scattering, were performed to determine the adsorption amount of AGC16, and the layer structures and the molecular assembly mechanism in the AGC16@SR and PAGC16@SR systems, respectively. For comparison purposes, the polymerizable cationic surfactant with one head group and a single alkyl chain, acryloyloxyethyl-N,N-dimethyl-N-cetylammonium bromide (referred to as ASC16), as well as the systems of ASC16@SR and PASC16@SR were also investigated in parallel. It was found that AGC16 molecules and their aggregates were simultaneously assembled into a shell layer, in which the saturated adsorption amount of AGC16 on SR is less than 1/2 that of ASC16, but the assembly layer of AGC16 is more hydrophobic with greater packing tightness compared with that of ASC16. It was also revealed that after in situ homopolymerization, the microcapsule shell becomes more compact. In the case of PAGC16@SR, the layers show higher surface roughness and irregularity compared with that of PASC16@SR. Moreover, the sustained release behavior of SR was also evaluated. The results revealed that PAGC16@SR performed well for SR controlled release, which was sorted by release performance as the following sequence: PAGC16@SR > AGC16@SR > PASC16@SR > ASC16@SR. Thus, the polymerizable cationic gemini surfactant holds substantial potential to be developed as an ideal candidate of soft matter to construct efficient controllable release systems.

Photorheologically reversible micelle composed of polymerizable cationic surfactant and 4-phenylazo benzoic acid

A photorheologically reversible micelle composed of polymerizable cationic surfactant n-cetyl dimethylallyl ammonium chloride (CDAAC) and trans-4-phenylazo benzoic acid (trans-ACA) was prepared. The effects of molar ratio of CDAAC/trans-ACA, time of UV and visible light irradiation and temperature on the rheological properties of micellar system were investigated. The results show that before UV irradiation the system with an optimum CDAAC/trans-ACA molar ratio of 1.4 forms viscoelastic micelles at 45°C. After 365nm UV irradiation, the viscosities of micelle systems with different concentrations at fixed molar ratio of 1.4 are decreased by 85%–95%. The CDAAC/trans-ACA (14mmol·L−1/10mmol·L−1) micelle system exhibits shear thinning property and its viscosity is decreased obviously with the increases of UV irradiation time less than 1h. The rheological process during UV irradiation for CDAAC/trans-ACA (14mmol·L−1/10mmol·L−1) micelle proves that viscosity, elastic modulus G′ and viscous modulus G″ will reduce quickly with the UV light. Furthermore, the micelle system after 1h UV-irradiation is able to revert to its initial high viscosity with 460nm visible light irradiation for 4h, and the micelle can be cycled between low and high viscosity states by repetitive UV and visible light irradiations. The UV–Vis spectra of CDAAC/trans-ACA micelle indicate that its photosensitive rheological properties are related closely to photoisomerization of trans-ACA to cis-ACA.

Interfacial Rheological Property and Rheokinetics of a Novel Photoreversible Micellar System

A new photorheologically reversible micelle composed of a polymerizable cationic surfactant N-cetyl dimethylallyl ammonium chloride (CDAAC) and trans-4-phenylazo benzoic acid (trans-ACA) was prepared. Exposing the CDAAC/trans-ACA (14 mM/10 mM) micellar system to the UV light (365 nm) resulted in a decrease in the relative viscosity, and in turn, the relative viscosity increases to its initial value when the micellar system was exposed to visible light (460 nm), which is caused by the photoisomerization of ACA. The interfacial tension and modulus of the micellar system change significantly after UV irradiation and show the reversible interfacial rheological properties when irradiated by visible light. Furthermore, for the first time the dynamic changing of the rheological properties, i.e., the decreasing of viscosity and viscoelasticity during the UV irradiation, has been studied and well described by a rheokinetics model.

The self-assembly properties of a series of polymerizable cationic gemini surfactants: Effect of the acryloxyl group

A new series of polymerizable cationic gemini surfactants bearing acryloxyl group in spacer and a variable alkyl chain length were synthesized and their surface active properties alongside with their self-assembly properties were investigated by surface tension measurement, electrical conductivity, fluorescence and dynamic light scattering (DLS) measurements. As compared to single-chain surfmer, this study shows that the gemini surfmers possess low critical micellar concentration (cmc) value and the surface tension value at cmc (γcmc). While compared to corresponding gemini surfactant without acryloxyl group, the introduction of the acryloxyl group into spacer results in a lower cmc value, higher degree of ionization and micropolarity of aggregate. The aggregates with large hydrodynamicradius (Rh) of 70–110nm as the main component were observed in the surfmer solution, while the size of aggregate constructed by corresponding gemini surfactant without acryloxyl group is far smaller than the former. All the results can be attributed to the existence of intramolecular dipolar interaction between the carbonyl of acryloxyl group and the cationic nitrogen atom. This increases the hydrophobicity and the regularity of the molecule, which induces the formation of tighter and larger size aggregate in comparison with corresponding gemini without the acryloxyl group on the spacer.

Investigation of structure–surface properties relationship of semi-fluorinated polymerizable cationic surfactants

Novel hybrid hydrocarbon/fluorocarbon ammonium type surfactant monomers (surfmers) of the general formula RF (CH2)l N(CH3)2(CH2)mOCOCH=CH2 with (RF=C4F9, C6F13, C8F17, l=4, 6, 11, and m=2–11) were synthesized and characterized. They exhibit very low surface tension as well as low critical micellar concentrations down to 1.39×10−5mol/L. Special attention was focused on theeffect of the polymerizable moiety, the length of the hydrocarbon spacers, and the fluorinated chains on surface activities of the reactive surfactants as compared to hydrocarbon surfmer analogs. Results indicate that the acrylic function has a pronounced effect on increasing the hydrophobic micelle character. This was confirmed by surface tensions and average surfaces occupied by these molecules at the water–gas interface. The micellar sizes were investigated by dynamic light scattering.

Mechanical properties, morphology, and crystal structure of polypropylene/chemically modified attapulgite nanocomposites

AbstractAtactic polypropylene (aPP) was chemically grafted onto attapulgite (ATP) via the bridge linking of a polymerizable cationic surfactant and poly(octadecyl acrylate) in the presence of ultrasonic oscillation and dicumyl peroxide, and then, the modified ATP was added to a polypropylene (PP) matrix to obtain PP nanocomposites by melt blending. The results of Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy confirmed that aPP and poly(octadecyl acrylate) were chemically grafted onto ATP through a graft polymerization reaction. The results of the mechanical properties testing showed that the addition of modified ATP improved the toughness and strength of PP remarkably. The dynamic mechanical analysis indicated that the modified ATP significantly increased the storage modulus and decreased the glass‐transition temperature of PP. The results of scanning electron microscopy and transmission electron microscopy showed that the modified ATP was uniformly dispersed into the PP matrix as crystal needles; this proved the presence of strong interactions between modified ATP and PP. The crystal structure analysis revealed that the β‐form crystalline of PP was formed within the modified ATP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Effect of Ionic Head Group on Admicelle Formation by Polymerizable Surfactants

AbstractOne of the problems of using surfactant‐modified adsorbents in a surfactant‐based adsorption process is loss of surfactant because of desorption. Recently, polymerizable surfactants have been used to minimize surfactant losses by polymerization of the surfactant admicellar structure to help secure it to the solid oxide surface. In this study, adsorption of polymerizable cationic gemini surfactant was used to form polymerized bilayers on silica. UV light was used to irradiate and initiate the polymerization process. Surfactant adsorption and desorption were evaluated to compare the efficiency of polymerized and non‐polymerized surfactants using gemini and conventional surfactants, respectively. Results demonstrate that the increased stability of the polymerized surfactant‐modified surface can reduce the desorption of surfactant from the surface, thereby improving operating characteristics of the surfactant‐modified media (e.g., maintaining adsolubilization potential, dispersion stability, etc.).

Synthesis and Characterization of Styrene-Butadiene Rubber-Clay Nanocomposites with Enhanced Mechanical and Gas Barrier Properties

Abstract Five styrene-butadiene rubber (SBR)/clay nanocomposite or hybrid systems were synthesized via mechanical mixing of SBR using a Brabender mixer and a 2-roll mill in the presence of unmodified sodium montmorillonite (Na-MMT) clay, MMT modified with octadecylamine (C18amine), MMT modified with a zwitterionic surfactant, octadecyldimethyl betaine (C18DMB), and MMT modified with a polymerizable cationic surfactant, vinylbenzyl octadecyldimethyl ammonium chloride (VODAC) or vinylbenzyl dodecyldimethyl ammonium chloride (VDAC). The surfactant chain length and functional groups affected the dispersion of clay nanolayers in the matrix and the overall properties of the nanocomposites. X-ray diffraction (XRD) revealed peaks corresponding to intercalated structures; transmission electron microscopy (TEM) observations agreed well with XRD assessment of the composites. SBR/VODAC-MMT system exhibited the best dispersion among the nanocomposites studied. VODAC-MMT was partially exfoliated in SBR matrix and the average aspect ratio of the nanolayer stacks or aggregates was high (20). Depending on the amount of clay, considerable mechanical reinforcement and gas barrier enhancement were achieved in nanocomposites over pure rubber. Tensile strength in excess of 18MPa was observed in SBR nanocomposites with 30 phr C18 organoclays. The storage modulus at 25C increased by a factor of four by incorporating 10 phr VODAC-MMT in SBR. The most pronounced oxygen barrier enhancement was again observed in SBR/VODAC-MMT nanocomposite with the reduction of permeability by 60% at silicate volume fraction of 0.06. The superior performance of nanocomposites containing VODAC-MMT is attributed to the presence of the vinyl-benzyl group and 18 carbon-atom tail in the surfactant leading to high compatibility with SBR and nano-scale dispersion in the SBR matrix.

Charged Rod‐Like Nanoparticles Assisting Single‐Walled Carbon Nanotube Dispersion in Water

AbstractA new dispersant for stabilization of single wall carbon nanotubes (SWNTs) in water that simultaneously utilizes three different dispersion or stabilization mechanisms: surfactant adsorption, polymeric wrapping, and Coulomb repulsive interaction, has been demonstrated. The new dispersant, a charged rod‐like nanoparticle (cROD), is a cylindrical micelle wrapped by negatively charged polymers which is fabricated by the aqueous free radical polymerization of a polymerizable cationic surfactant, cetyltrimethylammonium 4‐vinylbenzoate (CTVB), in the presence of sodium 4‐styrenesulfonate (NaSS). The surface charge density of the cRODs is controlled by varying the concentration of NaSS. Dispersions of SWNTs are obtained by sonicating a mixture of SWNTs and cROD in water, followed by ultra‐centrifugation and decanting. While the cRODs with neutral or low surface change densities (0 and 5 mol % NaSS) result in very low dispersion power and poor stability, the cRODs with high surface charge densities (15, 25, and 40 mol % NaSS) produce excellent dispersions with SWNT concentration as high as 437 mg L−1 and long term stability. The sharp van Hove transition peaks of the cROD assisted SWNT dispersions indicate the presence of individually isolated SWNTs. Atomic force microscopy and small angle neutron scattering analysis show that the dominant encapsulation structure of the cROD assisted SWNTs is surfactant assisted polymeric wrapping. SWNTs dispersed by the cRODs can be fully dried and easily re‐dispersed in water, providing enhanced processibility of SWNTs.

Gas barrier of polystyrene montmorillonite clay nanocomposites: Effect of mineral layer aggregation

AbstractThree polystyrene (PS)/clay hybrid systems have been prepared via in situ polymerization of styrene in the presence of unmodified sodium montmorillonite (Na‐MMT) clay, MMT modified with zwitterionic cationic surfactant octadecyldimethyl betaine (C18DMB) and MMT modified with polymerizable cationic surfactant vinylbenzyldimethyldodecylammonium chloride (VDAC). X‐ray diffraction and TEM were used to probe mineral layer organization and to expose the morphology of these systems. The PS/Na‐MMT composite was found to exhibit a conventional composite structure consisting of unintercalated micro and nanoclay particles homogeneously dispersed in the PS matrix. The PS/C18DMB‐MMT system exhibited an intercalated layered silicate nanocomposite structure consisting of intercalated tactoids dispersed in the PS matrix. Finally, the PS/VDAC‐MMT system exhibited features of both intercalated and exfoliated nanocomposites. Systematic statistical analysis of aggregate orientation, characteristic width, length, aspect ratio, and number of layers using multiple TEM micrographs enabled the development of representative morphological models for each of the nanocomposite structures. Oxygen barrier properties of all three PS/clay hybrid systems were measured as a function of mineral composition and analyzed in terms of traditional Nielsen and Cussler approaches. A modification of the Nielsen model has been proposed, which considers the effect of layer aggregation (layer stacking) on gas barrier. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1733–1753, 2007

Use of acrylic based surfmers for the preparation of exfoliated polystyrene–clay nanocomposites

Two polymerizable cationic surfactants, (11-acryloyloxyundecyl)dimethyl(2-hydroxyethyl)ammonium bromide (hydroxyethyl surfmer) and (11-acryloyloxyundecyl)dimethylethylammonium bromide (ethyl surfmer), were used for the modification of montmorillonite (MMT) clay. The modification of MMT dispersions was carried out by ion exchange of the sodium ions in Na +-MMT by surfactants in aqueous media. Modified MMT clays were then dispersed in styrene and subsequently polymerized in bulk by a free-radical polymerization reaction to yield polystyrene–clay nanocomposites. An exfoliated structure was obtained using the ethyl surfmer-modified clay, whereas a mixed exfoliated/intercalated structure was obtained using the hydroxyethyl surfmer-modified clay. Nanocomposite structures were confirmed by small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The nanocomposites exhibited enhanced thermal stability and an increase in glass transition temperature, relative to neat polystyrene. The nanocomposites also exhibited enhanced mechanical properties, which were dependent on the clay loading. Intercalated polystyrene–clay nanocomposites were obtained using the non-polymerizable surfactant-modified clay (cetyltrimethylammonium bromide). Nanocomposites made from mixtures of surfmer-modified and CTAB-modified clays were also prepared, showing intermediate properties. However, when the nanocomposites were prepared in solution only intercalated morphologies were obtained. This was attributed to the competition between the solvent molecules and monomer in penetrating into clay galleries. These nanocomposites also exhibited enhanced thermal stability relative to the virgin polystyrene prepared by the same method. Similar temperatures of degradation (at 50% decomposition) were found for these nanocomposites relative to those prepared by bulk polymerization.

Polymerizable Cationic Gemini Surfactant

A polymerizable cationic gemini surfactant, [CH(2)=C(CH(3))COO(CH(2))(11)N(+)CH(3))(2)CH(2)](2).2Br(-), 1 has been synthesized and its basic interfacial properties were investigated (in water and in the presence of 0.05 M NaBr). For comparison, the properties of monomeric surfactant corresponding to 1, CH(2)=C(CH(3))COO(CH(2))(11)N(+)(CH(3))(3).Br(-), 2, were also investigated. Parameters studied include cmc (critical micelle concentration), C(20) (required to reduce the surface tension of the solvent by 20 mN/m), gamma(cmc) (the surface tension at the cmc), Gamma(cmc) (the maximum surface excess concentration at the air/water interface), A(min) (the minimum area per surfactant molecule at the air/water interface), and cmc/C(20) ratio (a measure of the tendency to form micelles relative to adsorb at the air/water interface). For the polymerizable gemini surfactant, 1, the methacryloxy groups at the terminal of each hydrophobic group in a molecule have no contact with the air/water interface in the monolayer, whereas for the corresponding monomeric surfactant, 2, the methacryloxy group contacts at the interface forming a looped configuration like a bolaamphiphile. Polymerized micelles of the gemini surfactant are fairly small monodisperse and spherical particles with a mean diameter of 3 nm.

Stabilization of Catanionic Vesicles via Polymerization

Polymerizable cationic surfactant methacryloyloxyoctyl trimethylammonium bromide (MOTB) and anionic surfactant sodium 4-(omega-methacryloyloxyoctyl)oxy benzene sulfonate (MOBS) were synthesized. Stable catanionic vesicles can spontaneously form upon mixing the two oppositely charged surfactants in aqueous solution, which was further permanently fixed by polymerization. Surface tensiometry, nuclear magnetic resonance (NMR), static and dynamic laser light scattering (LLS), and cryogenic transmission electron microscopy (cryo-TEM) were used in combination to characterize the catanionic vesicles before and after polymerization. The kinetics of formation and breakdown of unpolymerized catanionic vesicles were studied in detail employing stopped-flow light scattering. In contrast to unpolymerized vesicles, the polymerized ones exhibit permanent stability under external perturbations such as dilution or adding excess MOTB. A tentative explanation is proposed about why free radical polymerization can successfully fix the catanionic vesicles, the structure of which is well-known to be in dynamic equilibrium exchange with unimers.

SANS studies of polymerized nano-particles using nonionic/cationic surfactant mixture

Mixtures of polymerizable cationic surfactant, cetyltrimethylammonium 4-vinylbenzoate (CTVB), nonionic surfactant, Triton X-100 (TX-100), and polymerizable hydrotropic salt, sodium 4-styrenesulfonate (NaSS) in aqueous solution were free radically polymerized to produce stable rod-like nano-particles with varying aspect ratio. A series of 1 wt% of the mixed surfactant (CTVB+TX-100) solutions were prepared with varying surfactant molar mixing ratio α (=TX-100/(TX-100+CTVB)) from 0.07 to 0.41. In all the samples, an appropriate amount of NaSS was added to keep the molar amount of CTVB plus NaSS constant at 0.0257 M; this maintained the amount of polymerizable counterions constant in all the samples. SANS measurements showed that the polymerized aggregates were cylindrical nano-particles which were stable against temperature variation between 30 and 60 °C. While the radius of the particles was constant at 2 nm, the aspect ratio was decreased from 27.5 to 2.7 as the mixing ratio α was increased from 0.07 to 0.23.

Polymerized Rodlike Nanoparticles with Controlled Surface Charge Density

Stable rodlike nanoparticles with highly controlled surface charge density have been developed by the free radical polymerization of the mixture of polymerizable cationic surfactant, cetyltrimethylammonium 4-vinylbenzoate (CTVB), and hydrotropic salt sodium 4-styrenesulfonate (NaSS) in aqueous solution. The surface charge of the polymerized CTVB/NaSS rodlike nanoparticles was controlled by varying the NaSS concentration during the polymerization process, and the charge variation was interpreted in terms of the overcharging effect in colloidal systems. The SANS measurements show that the diameter of the polymerized CTVB/NaSS rodlike nanoparticles is constant at 4 nm and the particle length ranges from 24 to 85 nm, depending on the NaSS concentration. The polymerized particles are longest when the NaSS concentration is 5 mol % which corresponds to the charge inversion or neutral point. The SANS and zeta potential measurements show that the Coulomb interactions between the particles are strongly dependent on the NaSS concentration and the zeta potential of the polymerized CTVB/NaSS nanoparticles changes from positive to negative (+12.8 approximately -44.2 mV) as the concentration of NaSS increases from 0 to 40 mol %. As the NaSS concentration is further increased, the zeta potential is saturated at approximately -50 mV.

Polymerization of Wormlike Micelles Induced by Hydrotropic Salt

Addition of the hydrotropic salt sodium tosylate (TSNa) to solutions of a polymerizable cationic surfactant, methacryloyloxyundecyltrimethylammonium bromide (MUTB), leads to a transition from spherical to wormlike micelles about 40 nm in length. The wormlike micelles were successfully polymerized to yield stable, single-phase solutions of polymerized micelles. The polymerized wormlike micelles were several hundred nanometers long, although their cross-sectional radius remained unchanged (∼2 nm). The spherical to wormlike micelle transition, and the wormlike micelles polymerized at different molar ratios of TSNa to MUTB, were characterized using quasi-elastic and static light scattering, small-angle neutron scattering, NMR, and cryogenic transmission electron microscopy.

Synthesis of unsaturated polyester‐clay nanocomposites using reactive organoclays

AbstractTwo polymerizable cationic surfactants, vinylbenzyl n‐alkyldimethyl (n = 12 or 18) ammonium chlorides, were used for functionalization of montmorillonite (MMT) and preparation of unsaturated polyester (UP)‐clay nanocomposites. Polymerizable organophilic clays were prepared by exchanging the sodium ions of MMT with vinylbenzyldodecyldimethyl ammonium chloride (VDAC) or vinylbenzyloctadecyldimethyl ammonium chloride (VOAC) in an aqueous medium. The dispersion of organoclays in UP led to gel formation. UP/VDAC‐MMT resulted in intercalated nanocomposites while UP/VOAC‐MMT formed partially exfoliated nanocomposites. The nanocomposites exhibited higher dynamic modulus than pristine UP.

Synthesis and dielectric properties of polystyrene‐clay nanocomposite materials

AbstractPolystyrene‐clay nanocomposite (PsCN) materials were synthesized and their properties of crystallinity, thermal behavior, and dielectric characteristics were investigated. A polymerizable cationic surfactant, [2‐(dimethylamino)ethyl]triphenylphonium bromide, was used for the intercalation of montmorillonite (MMT). The organophilic MMT was prepared by Na+‐exchanged MMT and ammonium cations of a cationic surfactant in an aqueous medium. Organophilic styrene monomers were intercalated into the interlayer regions of organophilic clay hosts followed by a free‐radical polymerization. Exfoliation to 2 wt % MMT in the polystyrene (PS) matrix was achieved as revealed by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Thermal properties by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were also studied. The dielectric properties of PsCNs in the form of film with clay loading from 1.0 to 5.0 wt % were measured under frequencies of 100 Hz–1 MHz at 25–70°C. A decreased dielectric constant and low dielectric loss were observed for PsCN materials. The dielectric response at low frequency that originated from dipole orientation was suppressed due to the intercalation of clay materials. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1368–1373, 2004