Surface Of Silica Microspheres Research Articles

Dispersive hierarchically porous composites based on defective MOFs as mixed-mode stationary phases for chromatographic separation.

Defective metal-organic frameworks-based composites with excellent separation properties were obtained. The mesoporous metal-organic frameworks were selected and deliberately designed to be deficient, and they were then combined with polyacrylamide to be modified on the surface of silica microspheres. The prepared composites were employed as mixed-mode stationary phase in chromatographic separation, and they were compared to both conventional microporous metal-organic framework-based columns and commercial columns. It showed improved selectivity and retention toward both hydrophilic and hydrophobic analytes, allowing for the effective separation of nine nucleosides and nucleobases, eight alkaloids, six antibiotics, and five alkylbenzenes. Additionally, the column was used to effectively separate the active ingredients in the daring substance of honeysuckle, revealing a wide range of possible applications. For the same batch of analytes, three batches of distinct materials demonstrated consistent separation effects. It also demonstrated excellent chromatographic repeatability and stability, with relative standard deviations of the retention time and/or column efficiency being found to be less than 0.8% and 0.9%, respectively. The dispersive hierarchically porous composites were demonstrated to be effective in chromatographic separation, and the results expanded the potential uses of defective MOFs with dispersed multi-level pores.

Utilization of composite particles with customizable cross-linked lignin patches for dental cleansing

Lignin, a natural polyphenol polymer, is a biocompatible, cost-effective and accessible material. To fully utilize the benefits of lignin, it is crucial to transform its complex macromolecules into nanoscale particles in a single solvent. In this research, an assembly-mediated internal cross-linking method in single solvent was proposed to manufacture cross-linked lignin colloidal particles with nanoscale particle size controlled to be around 50 nm. Then, cross-linked lignin composite particles with a unique “patchy” structure for dental cleansing were obtained by rapidly grafting the cross-linked lignin colloidal particles onto the surface of silica microspheres through the bridging effect of silane coupling agent. The resulting composite particles have rivets with adjustable hardness, significantly lower than traditional abrasives like silica in both hardness and modulus. Through the group cleansing behavior of soft interlocking, a breakthrough has been achieved in the high solid content agglomeration friction mode of traditional abrasives, which effectively reduces tooth wear and exhibits an excellent plaque removal effect.

Preparation, characterization, and separation mechanism of a dehydroabietic-acid-based shape-selective chromatographic stationary phase1

Chromatographic stationary phases with molecular-shape selectivity are advantageous for the separation and analysis of geometric isomers. Herein, dehydroabietic acid is bonded on the surface of silica microspheres via 3-glycidoxypropyltrimethoxysilane to form a monolayer dehydroabietic-acid stationary phase (Si-DOMM) with a racket-shaped structure. Various characterization techniques indicate that Si-DOMM is successfully prepared, and the separation performance of a Si-DOMM column is evaluated. The stationary phase has a low silanol activity and metal contamination and a high hydrophobicity and shape selectivity. The resolutions of lycopene, lutein, and capsaicin on the Si-DOMM column confirm that the stationary phase exhibits high shape selectivity. The elution order of n-alkyl benzene on the Si-DOMM column indicates its high hydrophobic selectivity and suggests that the separation is an enthalpy-driven process. Repeatability experiments reveal highly stable preparation processes of the stationary phase and column and indicate that the relative standard deviations of retention time, peak height, and peak area are less than 0.26%, 3.54%, and 3.48%, respectively. Density functional theory calculations using n-alkylbenzenes, polycyclic aromatic hydrocarbons, amines, and phenols as model solutes provide an intuitive and quantitative description of the multiple retention mechanisms. The Si-DOMM stationary phase exhibits superior retention and high selectivity for these compounds via multiple interactions. The bonding phase of the monolayer dehydroabietic acid stationary phase with a racket-shaped structure has a unique affinity for benzene, strong shape selectivity, and good separation performance for geometrical isomers with different molecular shapes.

Synthesis of core-shell material rich in carboxyl groups and its application in the selective adsorption of cationic peptides.

The ability to extract peptides and proteins from biological samples with excellent reusability, high adsorption capacity, and great selectivity is essential in scientific research and medical applications. Inspired by the advantages of core-shell materials, we fabricated a core-shell material using amino-functionalized silica as the core. Benzene-1,3,5-tricarbaldehyde and 3,5-diaminobenzoic acid were used as model organic ligands to construct a shell coating by alternately reacting the two monomers on the surface of silica microspheres. The resultant material featured an outstanding capability for the adsorption of cationic peptides, most likely owing to its porous structure, a large number of carboxylic functional groups, and low mass-transfer resistance. The maximum saturated adsorption capacity reached 833.3mg/g and the adsorption process took only 20min. Under optimized adsorption conditions, the core-shell material was used to selectively adsorb cationic peptides from the tryptic digestive solution of lysozyme and bovine serum albumin, Specifically, the analysis results showed seven cationic peptides in the eluate and twenty anionic peptides in the supernatant, which indicates the efficient trap of most cationic peptides in the digestive solution.

Extraction of benzoylurea insecticides from tea leaves based on thermoplastic polyethyleneimine embedded magnetic nanoparticle carbon materials

A novel mosaic structured core-shell composite, Silica@C/Ni (Sil@C/Ni), has been prepared by embedding Ni nanoparticles on the surface of silica microspheres via coordination and carbonization reduction, and was used as magnetic solid-phase extraction sorbents in combination with high performance liquid chromatography (HPLC) for the extraction and determination of four benzoylurea insecticides (BUs) in tea leaves. Based on the fact that hydrogen bonding and hydrophobic interactions exist between the material and BUs, allowing BUs on the surface of the material can achieve rapid mass transfer and improved sorption performance, satisfactory extraction recoveries have been achieved in practical sample applications. Under the optimized experimental conditions, the linear ranges were 0.5–200 µg L−1 for diflubenzuron and triflumuron, 1.0–200 µg L−1 for teflubenzuron and 0.8–200 µg L−1 for flufenoxuron with the correlation coefficients R2 ≥ 0.9991. The method has limits of detection and limits of quantification of 0.2–0.4 µg L−1 and 0.5–1.0 µg L−1, respectively. The intra-day and inter-day relative standard deviations were less than 5%. The actual sample recoveries were 76.63–95.26%. In addition, Sil@C/Ni was used repeatedly for 15 times and still showed a relatively satisfactory recovery of the four BUs. Therefore, Sil@C/Ni has a high stability and can be used as an ideal magnetic solid phase extraction sorbent for the trace enrichment of BUs in tea-leaf samples.

Facile and ultrasensitive electrochemical impedance sensing for formaldehyde based on silver ions doped in controllable and homogeneous silica microspheres

Formaldehyde is a highly reactive and toxic compound in air pollutants, exposure to even a low concentration of formaldehyde will do harm to human health. Herein, a novel electrochemical impedance sensor for formaldehyde has been developed based on Ag+-SiO2 microspheres prepared by the exchange of silver ions with trapped ammonium ions. The probe of silver ion is easily and selectively reduced by formaldehyde, then the silver nanoparticles would be generated. Exposure to more concentration of formaldehyde, more proportionate silver nanoparticles would be loaded on the surface of silica microspheres, and then the decrement of interface charge transfer resistance (Rct) would be obtained accordingly. The decrement of Rct was linear with the concentration of formaldehyde in the range from 2 to 6000 pmol L−1 with a detection limit of 0.5 pmol L−1. Enabled by such a unique sensing mechanism, the fabricated sensor has been successfully applied for the detection of formaldehyde in real samples with high performance in selectivity, low power consumption, sensitivity, cost-effectiveness, facility, and portability.

Preparation of CdTe nanocrystals doped fluorescent silica spheres by sol-gel method and their surface modification via thiol-ene chemistry

A facile one-step sol-gel method was used to prepare CdTe nanocrystals(NCs) doped silica microspheres with luxuriant thiol group on their surface using 3-mercaptopropyl trimethoxysilane(MPTMS) as organosilane in the aqueous solution. As the ligand and organosilane, MPTMS ensured the doping efficiency of CdTe NCs by ligand exchange and a large thiol group exposed to the solution to activate the surface of silica microspheres. The remodeled sol-gel process was performed at a lower temperature, which protected the thiol groups from degradation. Meanwhile, the particle size and size distribution can be controlled by varying synthesis conditions, such as the stirring rate and the reaction temperature. This user-friendly method provides a platform for immobilization of chemical groups such as carboxyl for combination of bioactive and diagnostic molecules at the surface of CdTe NCs doped silica microspheres through thiol-ene chemistry for high-throughput microarrays.

Tailoring bifunctional hybrid organic-inorganic nanoadsorbents by the choice of functional layer composition probed by adsorption of Cu2+ ions.

Spherical silica particles with bifunctional (≡Si(CH2)3NH2/≡SiCH3, ≡Si(CH2)3NH2/≡Si(CH2)2(CF2)5CF3) surface layers were produced by a one-step approach using a modified Stöber method in three-component alkoxysilane systems, resulting in greatly increased contents of functional components. The content of functional groups and thermal stability of the surface layers were analyzed by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, and 13C and 29Si solid-state NMR spectroscopy revealing their composition and organization. The fine chemical structure of the surface in the produced hybrid adsorbent particles and the ligand distribution were further investigated by electron paramagnetic resonance (EPR) and electron spectroscopy of diffuse reflectance (ESDR) spectroscopy using Cu2+ ion coordination as a probe. The composition and structure of the emerging surface complexes were determined and used to provide an insight into the molecular structure of the surfaces. It was demonstrated that the introduction of short hydrophobic (methyl) groups improves the kinetic characteristics of the samples during the sorption of copper(II) ions and promotes fixation of aminopropyl groups on the surface of silica microspheres. The introduction of long hydrophobic (perfluoroctyl) groups changes the nature of the surface, where they are arranged in alternately hydrophobic/hydrophilic patches. This makes the aminopropyl groups huddled and less active in the sorption of metal cations. The size and aggregation/morphology of obtained particles was optimized controlling the synthesis conditions, such as concentrations of reactants, basicity of the medium, and the process temperature.

Electrochemiluminescence Microscopy Imaging Using Ru(bpy)3 2+ Doped in Silica Microspheres

Electrochemiluminescence (ECL) is a controllable form of chemiluminescence where emission intensity is affected by a voltage imposed at an electrode surface. ECL microscopy imaging is a imaging technique aimed at light-emitting close to electrode surface with highly temporal and spatial resolution. Because ECL emitters are generated in situ at electrode surfaces, ECL imaging reflects the local surface reactivity and has a near-zero background. These features make ECL very useful in imaging applications, such as multiplexed ECL sandwich immunoassays, parallel single-cell analysis and latent fingerprints ECL imaging. Here we synthesized Ru(2,2’-bipyridine)3Cl2-doped silica (RuDS) microspheres via Stober method for single microsphere ECL imaging. The RuDS microsphere consisted of a silica core and a Ru(2,2’-bipyridine)3Cl2-doped silica shell via sol−gel process to immobilize Ru(bpy)3Cl2 into silica shell. Rougher sufaces and some defects indicated imperfect growth of Ru(2,2’-bipyridine)3Cl2-doped silica shell. We also noticed that RuDS microspheres tended to aggregate in the growth of Ru(2,2’-bipyridine)3Cl2-doped silica shell, since electrostatic interaction between Ru(bpy)3Cl2 and silica matrices decreased negatice charges on the surfaces of silica microspheres. Then an electrode modified with RuDS microspheres was placed in a cell under the microscope. The bright field image showed the positions of the RuDS microspheres. The bright ECL image of RuDS microspheres suggested that intermediates generated by electrooxidation of tripropylamine (TPA) can move up to several micron to cause the excitation of Ru(bpy)3Cl2. Interestingly, the ECL intensity from different single microspheres exhibited obvious distinctions, which may derive from local heterogeneity of electrode surface and RuDS microspheres. Moreover, the image sequences showed the areas without any microspheres also produced a weak ECL background signal, as a result of the electrooxidation of TPA itself. Simultaneously, the oxidation current of TPA in cyclic voltammetry and the ECL emission intensity of RuDS microspheres dramatically decreased along with increase of scan times, indicating the passivating of the surface of electrode was occured when the potential was applied. These results demonstrated that ECL microscopy imaging of single RuDS microsphere appearing high temporal and spatial resolution, is a powerful tool in terms of further understanding of detailed ECL mechanisms, both emiters and coreactants, and potential application in single molecule detection, etc.

Assembly of functional gold nanoparticle on silica microsphere

We demonstrate a controlled synthesis of silica microsphere with the surface-decorated functional gold nanoparticles. Surface of silica microsphere was modified by 3-aminopropypltriethoxysilane and 3-aminopropyldimethylethoxysilane to generate a positive electric field, by which the gold nanoparticles with the negative charges (unconjugated, thiolated polyethylene glycol functionalized with the traceable packing density and conformation) were able to be attracted to the silica microsphere. Results show that both the molecular conjugation on gold nanoparticle and the uniformity in the amino-silanization of silica microsphere influenced the loading and the homogeneity of gold nanoparticles on silica microsphere. The 3-aminopropyldimethylethoxysilane-functionalized silica microsphere provided an uniform field to attract gold nanoparticles. Increasing the ethanol content in aminosilane solution significantly improved the homogeneity and the loading of gold nanoparticles on the surface of silica microsphere. For the gold nanoparticle, increasing the molecular mass of polyethylene glycol yielded a greater homogeneity but a lower loading on silica microsphere. Bovine serum albumin induced the desorption of gold nanoparticles from silica microsphere, where the extent of desorption was suppressed by the presence of high-molecular mass polyethylene glycol on gold nanoparticles. This work provides the fundamental understanding for the synthesis of gold nanoparticle-silica microsphere constructs useful to the applications in chemo-radioactive therapeutics.

Preparation and evaluation of surface molecularly imprinted polymers as stationary phase columns for high performance liquid chromatography

Herein, highly selective surface molecularly imprinted polymers (SMIPs) were prepared at the surface of silica microspheres and employed as a new stationary phase for high performance liquid chromatography (HPLC).

Control over the distribution of luminescent impurities inside opal photonic crystals

The work is focused on the problem of control over the distribution of emitting centers inside photonic crystals. Two ways of luminescent impurity incorporation into synthetic silica opals are considered. First is based on the infiltration of the opal with a water solution of organic complexes (HEuEDTA) and leads to a formation of a uniform luminescent layer on the surface of silica microspheres. The other involves the infiltration of the structure with a heptane solution of CdSe quantum dots leading to the localization of the luminescent component around contact points between microspheres. Thus two different types of strongly ordered distribution of luminescent component inside opal can be obtained. Corresponding samples were prepared and their optical properties are discussed.

Efficient enrichment of glycopeptides using phenylboronic acid polymer brush modified silica microspheres.

For the development of rapid glycopeptide enrichment materials, conventional monolayer phenylboronic acid (PBA) based materials inevitably encounter many problems, such as low loading efficiency, long incubation time, and unsatisfactory selectivity. Extending the materials from a 1D monolayer to a 3D polymeric matrix will be one of the best candidates tackling these problems. In this work, a PBA-based polymer material (denoted as polyPBA@SiO2) was developed, in which flexible PBA polymer brushes were immobilized on the surface of silica microspheres, constructing an ideal platform for the efficient enrichment of glycopeptides. This material exhibits stronger interaction with glycopeptides in a higher concentration of organic solvent than in aqueous solution, resulting in the high binding capacity of 60 mg g-1. Moreover, higher selectivity for glycopeptides can be achieved with polyPBA@SiO2 than with both monolayer PBA modified silica and commercial PBA-agarose. These unique features of polyPBA@SiO2 could be attributed to the synergistic effect of polyvalent interactions provided by the polymer brush, specific interaction between PBA and glycopeptides and suppression of the non-specific binding of non-glycopeptides under high ACN concentration.

Grafting of poly[styrene‐co‐N‐(4‐vinylbenzyl)‐N,N‐diethylamine] polymer film onto the surface of silica microspheres and their application as an effective sorbent for lead ions

ABSTRACTAmino containing polymer of poly[styrene‐co‐N‐(4‐vinylbenzyl)‐N,N‐diethylamine] (PS‐co‐PVEA) was successfully grafted onto the surface of silica microspheres via the seed dispersion polymerization of styrene and N‐(4‐vinylbenzyl)‐N,N‐diethylamine in the presence of divinylbenzene employing the 3‐(methacryloxy)propyltrimethoxysilane activated silica microspheres as the seed. The polymerization led to thin chelating polymer films (30 nm) coated silica microspheres (silica@polymer) as determined by transmission electron microscopy. The synthesized silica@polymer composites were used as sorbents for lead ions (Pb2+). The adsorption properties, such as the pH effect, the adsorption kinetic, adsorption isotherm as well as the reuse of the silica@polymer sorbent were evaluated. The results demonstrated that the optimized adsorption condition was under neutral and the silica@polymer sorbent was efficient since it showed higher adsorption amounts (8.0 mg/g) and shorter adsorption equilibrium time (8 h) than that of the PS‐co‐PVEA microspheres and the pristine silica microspheres. Moreover, the silica@polymer sorbent was reusable even after four cycles of adsorption. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014, 131, 39973.

Transfer of electronic excitation energy from naphthalene to fluorophore indicator on the surface of silica microspheres with covalently or physically bound cyclodextrins

In order to use electronic excitation energy transfer (TE) for the detection of aromatic hydrocarbons (AHs) in a gas phase, TE from naphthalene (N) to a fluorophore indicator on the surface of silica microspheres (SMs) modified by covalently or physically adsorbed cyclodextrins (CDs) has been studied. It is found that dansylglycine (DG) is an appropriate acceptor of energy, because its absorption spectrum is shifted to the red region of the spectrum and overlaps well with the fluorescent spectra of AHs, while upon excitation at 290 nm its fluorescence is low. It has been demonstrated that, upon the introduction of SMs into the vapors of N and the excitation of N at 290 nm, the fluorescence of DG grows 500 nm more intensively than that of N. A method of quantitative variation of the N vapors pressure and, correspondingly, of the concentration of adsorbed N, based on the measurement of weight loss of the N solution in a nonvolatile solvent (DOS), has been developed. Using this method, the dependencies of intensity of fluorescence was determined for N and DG, as well as the efficiency of TE on the concentration of the adsorbed N. Under the assumption of the Forster mechanism of TE, the Forster radius (23.4 A) and the average distances between N and DG were estimated. It has been demonstrated that, upon excitation at the absorption band of N, the intensity of DG fluorescence linearly increases with the DG concentration, which makes it possible to use TE for the detection of low concentrations of N. The kinetics of fluorescence at the rapid introduction of the N vapors was studied: first the sorption of N on the surface and fast growth of monomeric F occurs; further, in ∼200 s, excimer fluorescence and TE arise. For SMs with adsorbed polymeric CDs, the efficiency of TE from N to DG is several times lower than for SMs with covalently bound CDs.

Study on the Preparation of Streptomycin Imprinted Polymers on the Surface of Silica Micro and Nano Spheres

The integration of molecular imprinting technique and solid-phase extraction (SPE) implements an effective alternative for sample pre-concentration in the determination and analysis of veterinary drug/pesticide residues. Herein, we reports a preliminary study on the preparation of streptomycin imprinted polymers on the surface of silica micro-spheres (with an average size of 50μm) and nano-spheres (with an average size of 500nm) via sol gel method. A mixed solution of tetrahydrofuran, ethanol and water (volume ratio is 7:1:1) was choose as dispersion agent, 3-aminopropyltriethoxysilane and phenyltriethoxysilane as functional monomers, and tetraethyl orthosilicate as cross-linker, while ammonia solution served as catalyst in the polymerization process. Scanning electron microscopic characterization was employed, suggesting that activating time exerts important influences on the morphology of activated silica micro-spheres, and also resultant molecular imprinted polymers (MIPs). The absorption capacity and selectivity of the obtained two MIPs were also evaluated for streptomycin and its analogue compounds in water samples. The results illustrate that the streptomycin-imprinted silica micro-spheres (MMIP) exhibited both larger absorption capacity and higher selectivity than those of silica nano-spheres (NMIP). The variant analytical performance might result from inadequate polymerization on the surface of silica nano-spheres.

Molecularly imprinted polymers on the surface of silica microspheres via sol‐gel method for the selective extraction of streptomycin in aqueous samples

Streptomycin-imprinted silica microspheres were prepared by combining a surface molecular-imprinting technique with the sol-gel method. A mixture of tetrahydrofuran, ethanol, and water (6:1:1, v/v/v) was selected as dispersing solvent while 3-aminopropyltriethoxysilane and triethoxyphenylsilane acted as functional monomers, and tetraethyl orthosilicate as a cross-linker. Characterization of the molecularly imprinted polymers was conducted using scanning electron microscope and dynamic binding experiments. As compared to the nonimprinted polymers, the imprinted polymers exhibited a higher degree of saturated adsorption volume up to 26.3 mg/g, and better selectivity even in an aqueous solution with interfering compounds, including dihydrostreptomycin, neomycin, and tetracycline. The adsorption ability and selectivity were observed to be influenced by the mole ratio of 3-aminopropyltriethoxysilane and triethoxyphenylsilane. Feasibility of the polymers to be used for actual application was also evaluated with spiked samples, indicating great potential for large-scale applications. Moreover, the streptomycin-imprinted polymers can be repeatedly used for 12 cycles without losing original performance, which is beneficial for commercial use.

Core–Shell–Shell Microsphere Catalysts Containing Au Nanoparticles for Styrene Epoxidation

An efficient heterogeneous nanocatalyst consisting of silica microsphere core decorated with Au nanoparticles shell encapsulated with a porous silica shell was successfully synthesized. The resulting core–shell–shell nanocatalyst catalyzed styrene epoxidation in toluene in the presence of a radical initiator and an oxidant tert-butyl hydroperoxide (TBHP) under inert atmosphere, giving ~100 % reactant conversion and 61 % selectivity towards the corresponding epoxide product at 80 °C. The maximum turnover frequency (TOF) of the catalyst was found to be 10400 h−1 at 80 °C under nitrogen atmosphere. The material also catalyzed trans-stilbene under similar condition, affording 52 % reactant conversion and 55 % selectivity towards trans-stilbene oxide product in 6 h. The catalyst was shown to be recycled and reused multiple times without losing its catalytic activity. Moreover, the Au nanoparticles in the catalyst did not undergo any significant leaching during the catalytic reactions. Porous SiO2–AuNPs–SiO2 core–shell–shell microsphere catalyst for epoxidation reaction was successfully synthesized. The catalyst was synthesized by anchoring Au nanoparticles (AuNPs) on the surface of silica microspheres, then encapsulating the AuNPs with silica shells and finally etching the outer silica shells into nanoporous silica shells. The catalyst exhibited heterogeneous catalytic activity for epoxidation of styrene and trans-stilbene and was proven to be easily recyclable and reusable in multiple cycles without significant loss of catalytic activity.

YVO4:Eu3+functionalized porous silica submicrospheres as delivery carriers of doxorubicin

Porous silica microspheres were fabricated by a facile surface-protected etching strategy. Polyvinylpyrrolidone (PVP) was used as a protecting polymer absorbed on the surface of silica microspheres and NaOH was employed as an etching agent. Owing to the protective action of PVP and inhomogeneous etching, mesopores were created in the silica microspheres. Then, based on the Pechini-type sol-gel and impregnating process, YVO(4):Eu(3+) nanocrystals were integrated into the channels to form highly luminescent YVO(4):Eu(3+)@SiO(2) composite microspheres. The biocompatibility tests on L929 fibroblast cells using MTT assay reveal low cytotoxicity of the system. Owing to the large interior space and electrostatic interaction, the porous microspheres show a relatively high loading capacity (438 mg DOX/YVO(4):Eu(3+)@SiO(2) g) and encapsulation efficiency (87.6%) for the anti-cancer drug doxorubicin hydrochloride (DOX). The drug release behavior and cytotoxic effect against human cervical carcinoma cells (HeLa cells) of the DOX-loaded YVO(4):Eu(3+)@SiO(2) carriers were investigated in vitro. It was found that the carriers present a highly pH-dependent drug release behavior due to electrostatic interaction between the silica surface and DOX molecules. The drug release rate became greater at low pH owing to the increased electrostatic repulsion. The DOX-loaded carriers demonstrate a similar or even greater anti-cancer activity with respect to the free DOX against HeLa cells. Furthermore, the PL intensity of the microspheres shows correlation with the cumulative release of DOX. These results suggest that the composite can potentially act as a multifunctional drug carrier system with luminescent tagging and pH-controlled release properties.

Preparation, characterization, and infrared emissivity property of optically active polyurethane/TiO 2/SiO 2 multilayered microspheres

Optically active polyurethane/titania/silica (LPU/TiO 2/SiO 2) multilayered core–shell composite microspheres were prepared by the combination of titania deposition on the surface of silica spheres and subsequent polymer grafting. LPU/TiO 2/SiO 2 was characterized by FT-IR, UV–vis spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), SEM and TEM, and the infrared emissivity value (8–14 μm) was investigated in addition. The results indicated that titania and polyurethane had been successfully coated onto the surfaces of silica microspheres. LPU/TiO 2/SiO 2 exhibited clearly multilayered core–shell construction. The infrared emissivity values reduced along with the increase of covering layers thus proved that the interfacial interactions had direct influence on the infrared emissivity. Besides, LPU/TiO 2/SiO 2 multilayered microspheres based on the optically active polyurethane took advantages of the orderly secondary structure and strengthened interfacial synergistic actions. Consequently, it possessed the lowest infrared emissivity value.