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     

Synthesis of Polystyrene/Hydrophobic SiO2 Composite Particles via Oil‐in‐Water Pickering Emulsion Polymerization

The aim of this work is to present a facile Pickering emulsion polymerization method for the synthesis of submicron polystyrene/SiO₂ core/shell composite particles. The commercial hydrophobic SiO₂ nanoparticles were used as stabilizing agent for creating a stable oil‐in‐water emulsion. Although the adsorption of hydrophobic SiO₂ nanoparticles in the emulsion system was unfavorable in terms of thermodynamics, by ultrasound treatment, self‐assembly of hydrophobic SiO₂ nanoparticles effectively stabilized oil‐in‐water Pickering emulsions during polymerization. Using 3 wt.% SiO₂ nanoparticles (based on styrene monomer) and 1:10 volume ratio of styrene monomer:water, the composite particles having average size of 790 nm and relatively narrow particles distribution were produced. With decreasing the volume ratio, smaller composite particles were created. Results from scanning electron microscope revealed that SiO₂ nanoparticles were located exclusively at the surface of the polystyrene latex particles. The SiO₂ content, determined by thermogravimetric analysis, was 12.6 wt.% in the composite particles. The route reported here may be used for the preparation of other composite nanostructures. POLYM. ENG. SCI., 59:E195–E199, 2019. © 2018 Society of Plastics Engineers     

Fabrication and properties of polysilsesquioxane-based trilayer core–shell structure latex coatings with fluorinated polyacrylate and silica nanocomposite as the shell layer

Polysilsesquioxanes (PSQ)-based core–shell fluorinated polyacrylate/silica hybrid latex coatings were synthesized with PSQ latex particles as the seeds, and methyl methacrylate, butyl acrylate, 3-(trimethoxysilyl) propyl methacrylate (MPS)-modified SiO₂ nanoparticles (NPs), 1H,1H,2H,2H-perfluorooctyl methacrylate (PFOMA) as the shell monomers by emulsifier-free miniemulsion polymerization. The results of Fourier transform IR spectroscopy, transmission electron microscopy, and dynamic light scattering suggested the obtained hybrid particles emerged with trilayer core–shell pattern. Contact angle analysis, x-ray photoelectron spectroscopy, and atom force microscopy results indicated that the hybrid film containing SiO₂ NPs showed higher hydrophobicity, lower surface free energy and water absorption, in comparison with the control system (without SiO₂ NPs). Compared with the control system, the hybrid latex film containing SiO₂ NPs in the fluorinated polyacrylate shell layer showed the higher content of fluorine atoms and a rougher morphology on the film surface. Additionally, thermogravimetric analysis demonstrated the enhanced thermostability of PSQ-based nanosilica composite fluorinated polyacrylate latex film.     

Architecture of colloidal crystals constructed by silica hybrid nanoparticles

Silica (SiO₂)‐crosslinked polystyrene (PS) particles possessing photofunctional N,N‐diethyldithiocarbamate (DC) groups on their surface were prepared by the free‐radical emulsion copolymerization of a mixture of SiO₂ (diameter D_n = 192 nm), styrene, divinyl benzene, 4‐vinylbenzyl N,N‐diethyldithiocarbamate (VBDC), and 2‐hydroxyethyl methacrylate with a radical initiator under UV irradiation. In this copolymerization, the inimer VBDC had the formation of a hyperbranched structure by a living radical mechanism. These particles had DC groups on their surface. Subsequently, poly(methyl methacrylate) brushes encapsulated SiO₂ particles were synthesized by the grafting from a photoinduced atom transfer radical polymerization (ATRP) approach of methyl methacrylate initiated by SiO₂‐crosslinked PS particles as a macroinitiator. We constructed the colloidal crystals using these photofunctional particles. Moreover, the SiO₂ particle array of colloidal crystals was locked by radical photopolymerization with vinyl monomer as a matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of nano‐SiO2 on granule characteristic and fusion process of Poly(vinyl chloride‐co‐vinyl acetate)/nano‐SiO2 composite resin

Poly(vinyl chloride‐co‐vinyl acetate) (PVVA)/nano‐SiO₂ composite resin was prepared by radical suspension polymerization of the monomers in the presence of fumed nano‐SiO₂ particles premodified with γ‐methylacryloxypropyl trimethoxysilane. The cool dioctyl phthalate absorption percentage, granule porosity, and specific surface area of the composite resin were enhanced through incorporation of nano‐SiO₂ into the PVVA. Scanning electron microscope pictures showed the resin had higher porosity. PVVA/nano‐SiO₂ composite resin was mixed with pure PVC resin to form a mixture sample (polymer‐composite blend [PCB]) and the mixture was fused in the torque rheometer. The rheological test results indicated that, at a certain nano‐SiO₂ content, the fusion speed of PCB was accelerated and the fusion temperature of PCB was decreased, owing to nano‐SiO₂ dispersed evenly in the polymer matrix. When excessive nano‐SiO₂ was loaded, the fusion torque, the fusion time, and the fusion temperature of PCB were all increased. These properties are correlative to the dispersive density of nano‐SiO₂ in the polymer matrix. This study also demonstrated that the introduction of small amounts of nano‐SiO₂ into the resin increased the impact strength and tensile strength of PCB simultaneously. J. VINYL ADDIT. TECHNOL., 20:230–236, 2014. © 2014 Society of Plastics Engineers     

Synthesis and characterization of PT/PS/SiO2 nanocomposite in nonaqueous medium by chemical method

The PT/PS/SiO₂ nanocomposite of polythiophene (PT), polystyrene (PS), and SiO₂ with a grain size of 100–150 nm was synthesized by chemical polymerization using FeCl₃ oxidant in nanoqueous medium (CHCl₃). The properties of PT/PS/SiO₂ synthesized were compared to those of PT, PT/PS, and PT/SiO₂ synthesized in the same conditions. The synthesized materials were subsequently characterized by FTIR spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The incorporation of PT in the composite was endorsed by FTIR studies. TGA revealed enhanced thermal stability of the PT/PS/SiO₂ nanocomposite compared to that of PT. SEMs showed globular particles and the presence of clusters of composite particles. The conductivity of the PT/PS/SiO₂ nanocomposite was measured as 1.30×10^?7 Scm^?1 and the conductivity value of PT (1.02×10^?4 Scm^?1) decreased with entiring PS and SiO₂ to PT structure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 746–752, 2005     

Preparation of core–shell poly(acrylic acid)/polystyrene/SiO2 hybrid microspheres

Core–shell poly(acrylic acid)/polystyrene/SiO₂ (PAA/PS/SiO₂) hybrid microspheres were prepared by dispersion polymerization with three stages in ethanol and ethyl acetate mixture medium. Using vinyltriethoxysilane (VTEOS) as silane agent, functional silica particles structured vinyl groups on surfaces were prepared by hydrolysis and polycondensation of tetraethoxysilane and VTEOS in core stage. Then, the silica particles were used as seeds to copolymerize with styrene and acrylic acid sequentially in shell stage I and stage II to form PAA/PS/SiO₂ hybrid microspheres. Transmission electron microscope results show that most PAA/PS/SiO₂ hybrid microspheres are about 40 nm in diameter, and the silica cores are about 15 nm in diameter, which covered with a layer of PS about 7.5‐nm thick and a layer of PAA about 5‐nm thick. This core–shell structure is also conformed by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and differential scanning calorimetry. FTIR results show that silica core, PS shell, and PAA outermost shell are bonded by covalents. In the core–shell PAA/PS/SiO₂ hybrid microsphere, the silica core is rigidity, and the PAA outermost shell is polarity, while the PS layer may work as lubricant owning to its superior processing rheological property in polymer blending. These core–shell PAA/PS/SiO₂ hybrid microspheres have potential as new materials for polar polymer modification. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1729–1733, 2006     

Syntheses of an azo‐group‐bound silica initiator and silica–polystyrene composites

In this article, we present a facile method for the synthesis of an azo‐group‐bound silica (SiO₂–azo) initiator. The azo groups were introduced onto the surface of silica (SiO₂) nanoparticles via facile condensation between 4,4′‐azobis‐4‐cyanopentanoic acid and the alkyl–hydroxyl groups ‐ immobilized on the SiO₂ nanoparticle surface under ambient conditions. The polystyrene (PS) chains were grafted onto the SiO₂ nanoparticle surface by in situ polymerization with the resulting SiO₂–azo as an initiator, and then, the SiO₂–PS composite was prepared. The syntheses and properties of the SiO₂–azo initiator and the composite were characterized by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, thermogravimetric analysis, gel permeation chromatography, and differential scanning calorimetry techniques. The results confirm that the SiO₂–azo initiator and the composite were synthesized successfully. Styrene was polymerized with the initiation of SiO₂–azo, and the resulting PS domain accounted for 48.6% of the total amount of composite. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation of hydrophobic SiO<Subscript>2</Subscript>@(TiO<Subscript>2</Subscript>/MoS<Subscript>2</Subscript>) composite film and its self-cleaning properties

TiO₂/MoS₂ composite was encapsulated by hydrophobic SiO₂ nanoparticles using a sol–gel hydrothermal method with methyltriethoxysilane (MTES), titanium tetrachloride (TiCl₄), and molybdenum disulfide (MoS₂) as raw materials. Then, a novel dual functional composite film with hydrophobicity and photocatalytic activity was fabricated on a glass substrates via the combination of polydimethylsiloxane adhesives and hydrophobic SiO₂@(TiO₂/MoS₂) composite particles. The influence of the mole ratios of MTES to TiO₂/MoS₂ (M:T) on the wettability and photocatalytic activity of the composite film was discussed. The surface morphology, chemical compositions, and hydrophobicity of the composite film on the glass substrate were investigated by scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and water contact angle (water CA) measurements. The results indicated that the composite film exhibited stable superhydrophobicity and excellent photocatalytic activity for degradation of methyl orange (MO) even after five continuous cycles of photocatalytic reaction when M/T was 7:1. The water CA and degradation efficiency for MO remained at 154° and 94%, respectively. Further, the composite film showed a good non-sticking characteristic with the water sliding angle (SA) at about 4°. The SiO₂@(TiO₂/MoS₂) composite consisting of hydrophobic SiO₂ nanoparticles and TiO₂/MoS₂ heterostructure could provide synergistic effects for maintaining long-term self-cleaning performance.     

Thermal and morphological studies on γ‐Fe2O3 polystyrene composites and the affect of additives

γ‐Fe₂O₃polystyrene (PS) composite films were prepared by a gel‐casting technique to obtain monodisperse composite films. To understand the effect of additives on the prepared composite films, additives such as rice husk ash and thiourea were made to disperse into the PS matrix. The as‐prepared γ‐Fe₂O₃ PS composite films, along with their additives, were subjected to characterization and study by X‐ray diffraction, scanning electron microscopy, thermal, IR, and dielectric measurement techniques. These studies showed monodisperse and chemically homogenous composite films with an increase in thermal behavior. An interesting self‐assembly of rod‐like nanoparticles of γ‐Fe₂O₃ particles into the polymer matrix, which formed spherical packets, was observed for the γ‐Fe₂O₃PS composite film. The electrical behavior of these films was interesting, as some showed conduction whereas others showed an increase in dielectric behavior. This nature was explained by the dielectric measurements. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 778–788, 2004     

Facile preparation of superhydrophobic polyester surfaces with fluoropolymer/SiO2 nanocomposites based on vinyl nanosilica hydrosols

A facile method to prepare superhydrophobic fluoropolymer/SiO₂ nanocomposites coating on polyester (PET) fabrics was presented. The vinyl nanosilica (V? SiO₂) hydrosols were prepared via one‐step water‐based sol‐gel reaction with vinyl trimethoxy silane as the precursors in the presence of the base catalyst and composite surfactant. Based on the V? SiO₂ hydrosol, a fluorinated acrylic polymer/silica (FAP/SiO₂) nanocomposite was prepared by emulsion polymerization. The FAP/SiO₂ nanocomposites were coated onto the polyester fabrics by one‐step process to achieve superhydrophobic surfaces. The results showed that silica nanoparticles were successfully incorporated into the FAP/SiO₂ nanocomposites, and a specific surface topography and a low surface free energy were simultaneously introduced onto PET fibers. The prepared PET fabric showed excellent superhydrophobicity with a water contact angle of 151.5° for a 5 μL water droplet and a water shedding angle of 12° for a 15 μL. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40340.     

Silica/polystyrene and silica/polystyrene‐b‐polymethacryloxypropyltrimethoxysilane hybrid nanoparticles via surface‐initiated ATRP and comparison of their wettabilities

Both silica/polystyrene (SiO₂/PS) and silica/polystyrene‐b‐polymethacryloxypropyltrimethoxysilane (SiO₂/PS‐b‐PMPTS) hybrid nanoparticles were synthesized via surface‐initiated atom transfer radical polymerization (SI‐ATRP) from SiO₂ nanoparticles. The growths of all polymers via ATRP from the SiO₂ surfaces were well controlled as demonstrated by the macromolecular characteristics of the grafted chains. Their wettabilities were measured and compared by water contact angle (WCA) and surface roughness. The results show that the nanoparticles possess hydrophobic surface properties. The static WCA of SiO₂/PS‐b‐PMPTS hybrid nanoparticles is smaller than that of SiO₂/PS hybrid nanoparticles, meanwhile, the surface roughness of SiO₂/PS‐b‐PMPTS hybrid nanoparticles is yet slightly rougher than that of SiO₂/PS hybrid nanoparticles, which shows that the combination and competition of surface chemistry and roughness of a solid material can finally determine its wettability. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers     

Preparation and characterization of polysiloxane–polyacrylates composite latices and their film properties

Gamma‐ray induced seeded emulsion polymerization of methyl methacrylate and butyl acrylate was carried out in the presence of a polymerizable polysiloxane seed latex, obtained by ring‐opening copolymerization of octamethyl cyclotetrasiloxane (D₄) and tetramethyl tetravinyl cyclotetrasiloxane (VD₄), catalyzed by dodecylbenzene sulfonic acid (DBSA). A series of polysiloxane seed latices with different molecular weights, vinyl contents and particle sizes was used. The conversion–time curve showed that the polymerization rate was accelerated significantly by the seed latex. The obtained composite latices also showed good storage stability, mechanical stability and high electrolyte resistance ability. By using transmission electron microscopy (TEM), the morphology of the composite latex particles was found to display a quite uniform fine structure. The graft polymerization reactions between the polymerizable polysiloxane and the acrylates were confirmed by Fourier‐transform infrared spectroscopy (FT‐IR) and the graft efficiencies were also studied. The influence of seed content, molecular weight, vinyl content of the polysiloxane and seed latex particles size on the mechanical performance, water absorption ratio, surface properties and transparency of the latex films was also investigated. It was found that the seed content and particles size greatly affect the mechanical performance, water absorption ratio and transparency of the latex films. Copyright © 2005 Society of Chemical Industry     

Synthesis of polystyrene/poly(butyl acrylate) core–shell latex and its surface morphology

A polystyrene (PS)/poly(butyl acrylate) (PBA) composite emulsion was produced by seeded emulsion polymerization of butyl acrylate (BA) with PS seed particles which were prepared by emulsifier‐free polymerization of styrene with potassium persulfate (KPS) under a nitrogen atmosphere at 70°C for 24 h with stirring at 60 rpm and swelled with the BA monomer in an ethanol/water medium. The structure of the PS/PBA composite particles was confirmed by the presence of the characteristic absorption band attributed to PS and PBA from FTIR spectra. The particles for pure PS and PS/PBA with a low content of the BA monomer were almost spherical and regular. As the BA monomer content was increased, the particle size of the PS/PBA composite particles became larger, and more golf ball‐like particles were produced. The surface morphology of the PS/PBA composite particles was investigated by AFM and SEM. The T_g's attributed to PS and PBA in the PS/PBA composite particles were found at 110 and ?49°C, respectively. The thermal degradation of the pure PS and PS/PBA composite particles occurred in one and two steps, respectively. With an increasing amount of PBA, the initial thermal decomposition temperature increased. On the contrary the residual weight at 450°C decreased with an increasing amount of PBA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 595–601, 2003     

Fabrication of covalently-bonded polystyrene/SiO<Subscript>2</Subscript> composites by Pickering emulsion polymerization

Pickering emulsion polymerization has attracted considerable attention in material fabrication due to its unique surfactant-free character and versatile association of oil, water and particles for a large set of materials. In this study, SiO₂ modified with Methacryloxypropyltrimethoxysilane (MPTMS) was employed to prepare Pickering emulsion, and subsequently covalently-bonded polystyrene/SiO₂(PS/SiO₂) composites were synthesized by Oil-in-water Pickering emulsion polymerization. Optical micrograph, contact angle, thermogravimetric analysis (TGA), Fourier transform infrared spectra (FT-IR), scanning electron microscope (SEM) and dynamic laser scattering (DLS) were employed to characterize the modified SiO₂, Pickering emulsion and prepared composites. It was found that prepared composites possess ragged surface morphology and SiO₂ concentration has an important effect on the morphology of as-prepared composites. In addition, covalent bond between PS core and SiO₂ shell was evidenced by FT-IR.     

Structure,morphology, and properties of HNBR filled with N550, SiO2, ZDMA,and two of three kinds of fillers

The vulcanization properties, mechanical properties of hydrogenated nitrile rubber (HNBR) filled with carbon black (N550), zinc dimethacrylate (ZDMA), SiO₂ independently and two of three kinds of fillers together were investigated, respectively. The filler‐dispersion was characterized by the transmission electron microscopy (TEM) and dynamic mechanical properties. The results showed that HNBR composite filled with SiO₂ or ZDMA displayed high tensile strength, elongation at break and compression set. The HNBR composite filled with N550 displayed low compression set, tensile strength and elongation at break. The dispersion of SiO₂ in HNBR compound was better than that in HNBR vulcanizates because of SiO₂ particles self‐aggregation in vulcanizing processing. ZDMA particles with micron rod‐like and silky shape in HNBR compounds changed into near‐spherical poly‐ZDMA particles with nano size in HNBR vulcanizates by in situ polymerization reaction. The N550 particles morphology exhibited no much change between HNBR compounds and vulcanizates. N550/ZDMA have the most effective reinforcement to HNBR and the appropriate amount of ZDMA is about 25% of total filler amount by weights. The theory prediction for Payne effect (dispersion of the filler) shown by the dynamic properties is identical with actual state observed by TEM. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Ionic liquid mediated synthesis of silica/polystyrene core–shell composite nanospheres by radical dispersion polymerization

This report describes the novel preparation of silica/polystyrene (SiO₂/PS) core–shell composite nanospheres by in situ radical dispersion polymerization in an ionic liquid (IL). Silica nanoparticles were first surface modified by the silane coupling agent methacryloxypropyltrimethoxysilane (MPTMS), which is capable of copolymerizing with styrene and provided a reactive CC bond. Transmission electron microscopy (TEM) revealed core–shell morphology with smooth surfaces. X-ray photoelectron spectroscopy (XPS) analysis demonstrated that almost all of the SiO₂ nanoparticles were encapsulated by the polymer. The composite particles were also analyzed by FT-IR spectroscopy and thermogravimetric analysis (TGA). In principle, this simple and environmentally-friendly synthetic procedure can be employed to prepare other inorganic oxide-containing polymer composites.     

Preparation and performance of nano‐SiO2 stabilized Pickering emulsion type sizing agent for glass fiber

The nano‐SiO₂ particles modified by silane coupling agent A‐1100 were used for preparing the vinyl ester resin (VE) Pickering emulsion. The stable emulsion could be served as the film former of sizing agent for glass fiber (GF). The influence of the wettability and the addition amount of nano‐SiO₂ on the stability of film former emulsion was explored. The effect of nano‐SiO₂ Pickering emulsion type sizing agent on the properties of GF was investigated. SEM images show that there existed a layer of sizing agent film with nano‐SiO₂ particles evenly on the GF surface. The abrasion resistance of the sized GF reached 3,579 times and the stiffness was 69 mm. The strand integrity also performed well. The fracture strength of GF bundles treated by Pickering emulsion type sizing agent increased by 28.6% to 0.504 N/Tex compared with that of the unsized GF bundles. The interlaminar shear strength (ILSS) of GF/VE composites sized by self‐made sizing agent which contained nano‐SiO₂ has improved, compared to the unsized GF reinforced VE composite. POLYM. COMPOS., 37:334–341, 2016. © 2014 Society of Plastics Engineers     

Synthesis,characterization, and properties of polystyrene/SiO2 hybrid materials via sol–gel process

Isocyanate‐functionalized polystyrene (P(St‐co‐TMI)) was successfully synthesized by solution free radical polymerization, which was then used to react with (3‐aminopropyl) triethoxysilane (APTES) to prepare a precursor of polystyrene/inorganic composites (PS/SiO₂). To obtain PS/SiO₂ composites with chemical bond, the precursor was mixed with triethoxysilane (TEOS) under the sol–gel reaction condition. The chemical bond between the PS and SiO₂ particles made the crosslink network more stable and avoided aggregation compared with the physical connection and barely mechanical mixing. The Fourier transform infrared (FT‐IR) results indicate that the isocyanate group ( NCO) was completely reacted with APTES. The field‐emission scanning electron microscopy results show that the morphology of composites and the distribution of the particles, which exhibit good compatibility between organic and inorganic phases, and the inorganic particles show good spatial uniformity. The differential scanning calorimetry shows that the glass transition temperature (T_g) of the PS/SiO₂ composites was shifted to high temperature when the amount of APTES increased. The thermal degradation temperature of the PS/SiO₂ composites increases with the increasing of APTES content. Master curves at 200°C are constructed for the storage and loss modulus as well as complex viscosity. POLYM. COMPOS. 36:482–488, 2015. © 2014 Society of Plastics Engineers     

Improving the hydrophobic,water barrier and crystallization properties of poly(ethylene terephthalate) by incorporating monodisperse SiO2 particles

This paper details an improvement in the properties of poly(ethylene terephthalate) (PET) with respect to its use in petroleum engineering by incorporating uniform (monodisperse; 35 to 380 nm) silica (SiO₂) particles and polystyrene? SiO₂ core–shell particles by melt mixing. The resulting high‐performance nanocomposite (SNPET) films are presented. The results of contact angle and water absorption tests showed that the contact angle of the amorphous SNPET films increased from 72° to 118.5° as the core–shell particle load increased from 0 to 6.0 wt%. The contact angle reached 128.0° when the films were annealed. Decreasing the SiO₂ particle size demonstrably improved the SNPET film hydrophobicity and lowered the water diffusion coefficient, i.e. SiO₂ particles of 35 nm in size gave the greatest enhancement of water barrier properties. Results of transmission electron microscopy, scanning electron microscopy, atomic force microscopy and optical measurements showed the homogeneous particle dispersion and nanostructure in the SNPET films. Their transparency and haziness increased as the particle size decreased. Use of such core–shell structures meant that the uniform (monodisperse) SiO₂ particles could be dispersed homogeneously in PET, and effectively improved the surface, thermal and crystallization behavior of SNPET films to produce materials with high barrier stability against water. Copyright © 2010 Society of Chemical Industry