Sol-gel Reaction Of Tetraethyl Orthosilicate Research Articles

Silica 3D printed scaffolds as pH stimuli-responsive drug release platform

Silica-based scaffolds are promising in Tissue Engineering by enabling personalized scaffolds, boosting exceptional bioactivity and osteogenic characteristics. Moreover, silica materials are highly tunable, allowing for controlled drug release to enhance tissue regeneration. In this study, we developed a 3D printable silica material with controlled mesoporosity, achieved through the sol-gel reaction of tetraethyl orthosilicate (TEOS) at mild temperatures with the addition of different calcium concentrations. The resultant silica inks exhibited high printability and shape fidelity, while maintaining bioactivity and biocompatibility. Notably, the increased mesopore size enhanced the incorporation and release of large molecules, using cytochrome C as a drug model. Due to the varying surface charge of silica depending on the pH, a pH-dependent control release was obtained between pH 2.5 and 7.5, with maximum release in acidic conditions. Therefore, silica with controlled mesoporosity could be 3D printed, acting as a pH stimuli responsive platform with therapeutic potential.

Preparation of Sulfonated Poly(arylene ether)/SiO2 Composite Membranes with Enhanced Proton Selectivity for Vanadium Redox Flow Batteries

Proton exchange membranes (PEMs) are an important type of vanadium redox flow battery (VRFB) separator that play the key role of separating positive and negative electrolytes while transporting protons. In order to lower the vanadium ion permeability and improve the proton selectivity of PEMs for enhancing the Coulombic efficiency of VRFBs, herein, various amounts of nano-sized SiO2 particles were introduced into a previously optimized sulfonated poly(arylene ether) (SPAE) PEMs through the acid-catalyzed sol-gel reaction of tetraethyl orthosilicate (TEOS). The successful incorporation of SiO2 was confirmed by FT-IR spectra. The scanning electron microscopy (SEM) images revealed that the SiO2 particles were well distributed in the SPAE membrane. The ion exchange capacity, water uptake, and swelling ratio of the PEMs were decreased with the increasing amount of SiO2, while the mechanical properties and thermal stability were improved significantly. The proton conductivity was reduced gradually from 93.4 to 76.9 mS cm-1 at room temperature as the loading amount of SiO2 was increased from 0 to 16 wt.%; however, the VO2+ permeability was decreased dramatically after the incorporation of SiO2 and reached a minimum value of 2.57 × 10-12 m2 s-1 at 12 wt.% of SiO2. As a result, the H+/VO2+ selectivity achieved a maximum value of 51.82 S min cm-3 for the composite PEM containing 12 wt.% of SiO2. This study demonstrates that the properties of PEMs can be largely tuned by the introduction of SiO2 with low cost for VRFB applications.

Polyzwitterion-SiO2 Double-Network Polymer Electrolyte with High Strength and High Ionic Conductivity.

The key to developing high-performance polymer electrolytes (PEs) is to achieve their high strength and high ionic conductivity, but this is still challenging. Herein, we designed a new double-network PE based on the nonhydrolytic sol-gel reaction of tetraethyl orthosilicate and in situ polymerization of zwitterions. The as-prepared PE possesses high strength (0.75 Mpa) and high stretchability (560%) due to the efficient dissipation energy of the inorganic network and elastic characteristics of the polymer network. In addition, the highest ionic conductivity of the PE reaches 0.44 mS cm-1 at 30 °C owning to the construction of dynamic ion channels between the polyzwitterion segments and between the polyzwitterion segments and ionic liquids. Furthermore, the inorganic network can act as Lewis acid to adsorb trace impurities, resulting in a prepared electrolyte with a high electrochemical window over 5 V. The excellent interface compatibility of the as-prepared PE with a Li metal electrode is also confirmed. Our work provides new insights into the design and preparation of high-performance polymer-based electrolytes for solid-state energy storage devices.

Surface modification of recycled coir fibers with hybrid coating and its effect on the properties of ABS composites

In this work, a hybrid coating (TSMA) was produced using tetraethyl orthosilicate (TEOS)/KH550/Styrene maleic anhydride copolymer (SMA) as raw materials. The coating was afterwards applied to modify recycled coir (r-coir) fibers via dip-coating. R-coir fibers reinforced ABS composites were then prepared and the reinforcing effect of fibers on the composite structure was investigated, as well. The r-coir fibers coated with TSMA were hydrolyzed in air for 3 days. The SiO2 particles produced by sol-gel reaction of TEOS were used to connect KH550 and SMA to the surface of the fibers and form an organic-inorganic ‘armor’ structure. The successful surface modification of the r-coir fibers was proved via FTIR spectroscopic study and the improvement of their decomposition temperature was evidenced by TGA. Furthermore, the homogeneous dispersion of TSMA on the surface of r-coir fibers was observed via SEM. In addition, the tensile strength of single fibers was found to increase by 36.1%. According to the results, TSMA can be successfully homogenized on the fiber surface, enabling one to repair the damaged areas and improve the tensile strength of single fibers. Besides, good compatibility between r-coir fibers and ABS was revealed by contact angle measurements. Furthermore, the bending strength and elastic modulus of TSMA-modified r-coir fibers/ABS composites were improved by 6% and 27%, respectively. Therefore, the method of plant fiber modification proposed in present work provides a reliable way for effective reuse of r-coir fibers.

Hierarchical silica monolith prepared using cellulose monolith as template

Silica monoliths with a continuous porous structure have received much attention in biomedical and environmental applications owing to their high-performance separation/adsorption behaviors. However, it is difficult to maintain a porous structure in silica monoliths because their synthesis often involves complicated phase separation in sol-gel reactions. Herein, for the first time, we used an ecofriendly cellulose material as a template to prepare a hydrophilic and hierarchically porous silica monolith. The cellulose monolith template was prepared from cellulose acetate by a thermally induced phase separation method. The silica was then prepared in the presence of the cellulose monolith by a typical sol-gel reaction of tetraethyl orthosilicate (TEOS) to form the composite monolith, which was converted to the silica monolith by burning in air to remove the cellulose monolith. Owing to the hierarchically porous structure of the cellulose monolith template, the obtained silica monolith showed a similar hierarchically porous structure, as confirmed by scanning electron microscopy and nitrogen adsorption-desorption analyses. The pore structure could be controlled by changing the fabrication parameters, such as the kind of cellulose monolith and TEOS concentration. The surface-modified silica monolith was developed for further applications.

Continuous synthesis of plate-like silica microparticles using microfluidics

The synthesis of plate-like silica particles, which are of importance for a variety of applications, are mainly based on the widely adopted method of the sol-gel reaction of silicon alkoxides in traditional batch-wise instrumentation. In this study, continuous-flow synthesis of amorphous plate-like silica particles is reported through combining droplet-based microfluidics and the sol-gel reaction of tetraethyl orthosilicate. The reaction was conducted at the surface of oil droplets, comprising tetraethyl orthosilicate (TEOS), suspended in acidic (HCl) water, resulting in silica particles on the surface of the droplets, leaving the device with outlet flow. The synthesized particles had plate-like structure with thickness less than 1 μm and microscale in two other dimensions. The influences of experimental parameters (TEOS and HCl concentrations and the flow rate of aqueous phase) on the silica production rate were examined. With increase in the TEOS and HCl concentrations, the production rate increases monotonically. With increase in the flow rate of aqueous phase, the production rate increases up to a specific flow rate. Beyond the flow rate, the production rate decreases with increase in the flow rate. A phenomenological model is proposed to address the production rate using the droplet-based microfluidic system. In addition, response surface methodology (RSM) was used to statistically model and optimize the production rate. At optimum values for the experimental parameters, the experimentally measured production rate was considerably comparable to that predicted by RSM.

Surface modification of Kevlar fiber by nanoSiO2 deposition in supercritical fluid

ABSTRACTIn this work, we modified Kevlar fiber first by depositing nano SiO2 on its surface from sol-gel reaction of tetraethylorthosilicate (TEOS) and formic acid using supercritical carbon dioxide (scCO2) as the solvent. The results showed that the Kevlar fiber surface can be successfully deposited with nano SiO2 in this manner while its properties were hardly affected by the supercritical carbon dioxide environment. However, special attention needs to be given to an optimal scCO2 pressure for the purpose of enhancing the interfacial adhesion and shear strength between Kevlar fiber and epoxy resin as too low or too high pressures result in certain morphologies of deposited nano SiO2 particles that give rise to insufficient penetration of the resin into the fiber surface. Plasma treatment was found to provide a significant surface etching effect that is more effective than nano SiO2 deposition alone. Moreover, it has such a synergistic effect with nano SiO2 deposition that when they were employed sequentially, the interface between the Kevlar fiber and the epoxy resin has the strongest adhesion and shear strength, which are 83.6% higher than those in the original composite with no surface treatment.

Synthesis of polystyrene@silica particles through soap-free emulsion polymerization and sol-gel reaction on polymer surfaces

Polystyrene@silica particles were produced through soap-free emulsion polymerization (SFEP) of styrene and N-vinylacetamide (NVA) via the sol-gel reactions of tetraethyl orthosilicate (TEOS) on polymer particle surfaces. Different amounts of NVA were used to prepare polystyrene particles using the SFEP process. The particles covered with poly-NVA then underwent the Stöber process to form an outer silica shell. NVA was found to stabilize the polymer colloids and improve their stability by steric effects, even after the positive charge on the polymer surface was partially neutralized by the electrostatically adsorbed TEOS, which tends to induce particle aggregation. Further, the –NH functional groups on NVA catalyzed the hydrolysis of TEOS in the sol-gel reaction to form silica. Consequently, small, monodisperse, and stable core-shell particles were formed despite having a low zeta potential.

Synthesis and characterization of poly(N-isopropylacrylamide-co-acrylamide) mesoglobule core–silica shell nanoparticles

HypothesisHow to encapsulate poly(N-isopropylacrylamide) (PNIPAM) mesoglobule cores by silica shells greatly affects the resultant nanoparticle structures. Incorporation of acrylamide (AM) unit into PNIPAM in combination with 3-glycidyloxypropyltrimethoxysilane (GLYMO, as a coupling agent) effectively induces nucleation and growth of silica on PNIPAM core surfaces, where the –NH2 of acrylamide reacts with the epoxide of GLYMO while GLYMO further participates in subsequent sol-gel reaction of tetraethyl orthosilicate (TEOS), thereby leading to desirable particle morphology. ExperimentsPNIPAM-based core–silica shell nanoparticles were prepared by sol-gel reaction of TEOS and GLYMO in the presence of polymeric core particles. The major parameters investigated in a systematic fashion include acrylamide concentration and weight ratio of polymer:GLYMO:TEOS. GPC, DLS, DSC, FE-SEM, TEM, FTIR and TGA were then used to characterize polymeric cores and hybrid nanoparticles. FindingsThe particle morphology was governed primarily by the acrylamide content and the weight ratio of PNIPAM/AM:GLYMO:TEOS, and desirable hybrid nanoparticles with narrow particle size distribution were achieved. The LCST of PNIPAM-based mesoglobules increases with increasing acrylamide content. Encapsulation of PNIPAM-based mesoglobules with silica also reduces their thermo-sensitivity. This is the first report of developing a novel approach to prepare PNIPAM-based mesoglobule core–silica shell nanoparticles with controllable particle morphologies.

Inorganic/Organic Double-Network Ion Gels with Partially Developed Silica-Particle Network.

Tough inorganic/organic composite network gels consisting of a partially developed silica-particle network and a large amount of an ionic liquid, named micro-double-network (μ-DN) ion gel, are fabricated via two methods. One is a one-pot/one-step process conducted using a simultaneous network formation via sol-gel reaction of tetraethyl orthosilicate and free radical polymerization of N, N-dimethylacrylamide in an ionic liquid. When the network formation rates of the inorganic and organic networks are almost the same, the μ-DN structure is formed. The second method is simpler and involved the use of silica nanoparticles as the starting material. By controlling the dispersion state of the silica nanoparticles in an ionic liquid, the μ-DN structure is formed. In both μ-DN ion gels, silica nanoparticles partially aggregate and form network-like clusters. When a large deformation is induced in the μ-DN ion gels, the silica-particle clusters rupture and dissipate the loaded energy. The fracture stress and Young's modulus of the μ-DN ion gel increase as the size of the silica nanoparticles decreases. The increment in the mechanical strength would have been caused by the increase in the total van der Waals attraction forces and the total number of hydrogen bonding in the silica-particle networks.

High reflective efficiency and durability of multilayered core-shell composite particles with controlled shell thickness

Multilayered core-shell composite particles with a high reflective efficiency and durability were prepared by a subsequent formation of multilayered shells on silver-coated iron (Fe/Ag) microspheres. The SiO2 and TiO2 multilayered shells were formed onto the Fe/Ag microspheres by the sol-gel reaction of tetraethylorthosilicate (TEOS) and titanium n-butoxide (TBOT), respectively. The thickness uniformity of SiO2 and TiO2 shells was improved by ultrasonication during the sol-gel reaction process. The mechanical durability of the composite particles was also investigated by an ink grinder. The SiO2 and TiO2 multilayered shells showed high efficiency for preserving the reflectivity and increasing the durability of the Fe/Ag microspheres.

Synthesis of Polyurethane/Silica Modified Epoxy Polymer Based on 1,3-Propanediol for Coating Application

Studies on the synthesis of polyurethane/silica modified epoxy polymer using 1,3-propanediol has been conducted. Synthesis of polymers made by reaction of tolonate and 1,3-propanediol (ratio NCO/OH=2.5) as the building blocks of polyurethane with diglycidyl ether bisphenol A (DGEBA) epoxy and catalyst dibutyltin dilaurate (DBTL).The total weight of the polyurethane used was 20% (w/w) of the total epoxy. Based on Fourier Transform Infrared (FTIR) and 1H-Nuclear Magnetic Resonance (1H-NMR) spectra indicated the existence of a new bond that is formed from the reaction of isocyanate group and hydroxyl group, where the hydroxyl groups derived from epoxy and 1,3-propanediol. The addition of silica (5, 10, and 15% w/w to epoxy) into the epoxy-modified polyurethane has been carried out through sol-gel reaction of tetraethyl orthosilicate (TEOS). The isocyanate conversion rate for the addition of silica 5, 10, and 15% are 95.69; 100, and 100%, respectively. The morphology and element identification by Scanning Electron Microscopy/Energy Dispersive X-Ray Analysis (SEM/EDX), showed that Si element has been successfully added in the polymer. From the tensile strength and elongation analysis, also thermal stability analysis using Thermal Gravimetric Analyzer (TGA), the increase of silica amount into the polyurethane modified epoxy did not significantly affect to thermal properties, but decrease the tensile strength of the polymer.

Stretchable dual nanocomposite hydrogels strengthened by physical interaction between inorganic hybrid crosslinker and polymers

Stretchable hydrogels have been developed by fabricating a dual nanocomposite structure by polymerization of hydrophilic monomers and sol-gel reaction of tetraethyl orthosilicate (TEOS) in the presence of Laponite. The mechanical enhancement of the hydrogels was markedly influenced by monomer structure and contents of TEOS and Laponite. The strong interaction between N-isopropylacrylamide (NIPAM) and inorganic hybrid crosslinker was examined by dyeing experiment, transparency and fluorescence measurement of Laponite/SiO2/monomer dispersions. This accounted for the excellent mechanical properties of Laponite/SiO2/PNIPAM dual nanocomposite hydrogel. Uniaxial tensile tests showed improved tensile property (elongation at break: 1845±3.46%; fracture stress: 271.41±6.26kPa), and elastic modulus of the hydrogel significantly increased with TEOS contents and reached 26.69±6.13kPa at 10:1.0 of mLaponite:mTEOS. Fracture compression strength could reach 7.06±1.25MPa (fracture energy: 1185.53±5.57Jm−2), meanwhile it showed remarkable fatigue resistance. The embedded nano-SiO2 accounted for the significantly improved stiffness of the hydrogels. Moreover, the dual nanocomposite mechanism (the covalent bonding of SiO2 with Laponite and strong physical interaction of polymer chains with inorganic hybrid crosslinker) made a big contribution to the toughness of the gels. The noncovalent entanglements between SiO2 and polymer chains could promote both strength and elongation of the hydrogel, but the effect is not as notable as the covalent one.

Vapor-liquid interfacial reaction to fabricate superhydrophilic and underwater superoleophobic thiol-ene/silica hybrid decorated fabric for oil/water separation

With oil spill accidents and oil industrial wastewater increasing, oil/water separation has attracted much attention in recent years. Herein, we report the fabrication of superhydrophilic and underwater superoleophobic thiol-ene/silica hybrid decorated fabrics for oil/water separation via vapor-liquid interfacial reaction. It is based on sol-gel reaction of tetraethyl orthosilicate (TEOS) to generate silica and thiol-ene reaction between poly(ethylene glycol) dimethacrylate (PEGDMA) and trimethylolpropane tris(3-mercaptopropionate) (TTMP) to form crosslinked hydrophilic polymer on polyester fabric under the catalysis of butylamine/ammonia vapor. The chemical structure of the surfaces on thiol-ene/silica hybrid decorated fabric was confirmed by FTIR and XPS, and obvious micro-nano morphology and roughness were observed with SEM and AFM. The water contact angle of the fabric attained 0° in 0.36s, and the underwater oil contact angle reached up to 160°. Importantly, the fabric exhibited high separation efficiency at 99.5%, fast water flux above 71600Lm−2h−1 and excellent recyclability in oil/water separation. Our findings open a new strategy to fabricate organic-inorganic hybrid superhydrophobic and underwater superoleophobic materials for oil/water separation.

Preliminary Study on Tensile Properties of Electrospun Silica Fibers/Polypropylene Composites

Composites based on silica and glass fibers conventionally contain fibers with dimension in the range of a few micrometers to millimeters. Electrospinning technique allows fabrication of fibers in the submicron length scale. With smaller dimension, these fibers when applied as reinforcement in composites may yield interesting composite properties. In this paper, silica fibers fabricated via electrospinning were utilized as reinforcement in polypropylene-matrixed composites. The silica precursor was prepared by sol-gel reaction of tetraethyl orthosilicate, ethyl alcohol, de-ionized water and hydrochloric acid. Viscous silica precursor was made into fibers by electrospinning with electric field of 1 kV/cm. Electrospun non-woven fiber mats were stabilized at 200°C and calcined at 800°C to remove remaining organic residues. The fiber diameter average was 279±40 nm. In the process of making composites, the silica fiber mats were sandwiched between polypropylene sheets, and the layers were compression-molded together. The composite samples with varied silica fiber contents up to 2 wt% were mechanically tested. Tensile tests demonstrate slight increases in tensile modulus, tensile strength with increasing silica fiber content. However, silica fiber content within the experimental range does not have prominent effects on yield strength and strain at break.

One-step coating of silica onto multi-walled carbon nanotubes using polyethyleneimine for high electrical resistivity

Multi-walled carbon nanotubes (MWCNTs) were uniformly coated with silica using polyethyleneimine (PEI) as a coupling agent without subjecting the surfaces of the MWCNTs to chemical modification, such as an amine treatment or chemical oxidation. PEI was physically adsorbed onto the MWCNTs, and the silica coating process was performed through a sol-gel reaction of tetraethyl orthosilicate (TEOS) in ethanol under base catalytic conditions at room temperature. PEI was the best coupling agent for coating silica on MWCNTs among the various amphiphilic polymers and surfactant tested, which included Triton X-100, polyvinylpyrrolidone, polyethylene glycol, and sodium dodecyl sulfate. During the sol-gel process using PEI as a coupling agent, silica could be uniformly formed on MWCNTs without any structural defects. As the amount of TEOS used was increased, the thickness of coated silica layer and electrical resistivity of MWCNTs also increased (up to 5.3×1010 Ω sq−1) owing to the high surface coverage of silica on the MWCNTs.

Synthesis of Silica Nanotube Using Myelin Figure as Template and their Formation Mechanism.

Silica nanotubes are synthesized through a sol-gel reaction of tetraethyl orthosilicate (TEOS) using myelin figures of Pluronic P123 as the structure-directing agent. The simultaneous progression of the formation of molecular assemblies that act as templates and the formation of silica frameworks though a sol-gel reaction of the silica precursor is a characteristic of this reaction system. The synthesized silica nanotubes were characterized using transmission electron microscopy (TEM), nitrogen adsorption/desorption measurements, and Fourier-transform infrared spectroscopy (FT-IR). The silica nanotubes were unilamellar with diameters of approximately 30 nm, membrane thicknesses of approximately 10 nm, and lengths exceeding a few hundred nanometers. The Brunauer-Emmett-Teller (BET) specific surface area was 589.46 m(2)/g. Silica nanotubes can also be obtained using other Pluronic surfactants that can form myelin figures. In this work, we also investigated the formation mechanism of the silica nanotubes. The typical diameter of a myelin figure is a few tens of micrometers. However, myelin figures with diameters of approximately 10 µm can form in systems with TEOS because bifurcation is induced by minute silica nuclei that form during the initial reaction between TEOS and water. Freeze fracture TEM (FF-TEM) observations revealed the existence of myelin figures with diameters of 20 to 30 nm, which are the same size and shape as the synthesized silica nanotubes. These results indicate that bifurcation of the myelin figures is induced by the silica nuclei that form via the initial reaction of TEOS, which result in the formation of bifurcated myelin figures with diameters of ~10 µm. Myelin figures with diameters of 20 to 30 nm form on the surface, and they become templates where the reaction of TEOS progresses to form silica nanotubes with diameters of approximately 30 nm.

Preparation and comparative properties of membranes based on PANI and three inorganic fillers

In this study, we compare the effects of aniline-modified mesoporous silica (AMS), raw silica (ARS) and non- modified raw silica (NRS) particles on the physical properties of as-prepared polyaniline (PANI)-silica mesocomposites (PSM) and nanocomposites (PSN) and PANI-raw silica (PRSN) membranes. First, aniline-modified silica particles were synthesized by a conventional base-catalyzed sol-gel reaction of tetraethyl orthosilicate (TEOS) in the presence or absence of N-(3-(Trimethoxysilyl) propyl)aniline (PAPTMS). Subsequently, PSM, PSN and PRSN materials were prepared through in situ oxidation polymerization reaction of aniline monomer in the presence of AMS, ARS and NRS particles. It should be noted that all the properties of PSM membranes improved substantially from those of PSN and PRSN. For example, upon 3 wt% loading of AMS particles, 10, 25, 10, and 85% increases in thermal stability, mechanical strength, surface hydro - philicity and gas permeability were observed for PSM membranes, respectively, as well as more than 45% reduction in the thermal conductivity.

Sunlight-Induced Self-Healing of a Microcapsule-Type Protective Coating

Photopolymerization behavior of a methacryloxypropyl-terminated polydimethylsiloxane (MAT-PDMS) healing agent was investigated in the presence of benzoin isobutyl ether (BIE) photoinitiator by Fourier transform infrared (FT-IR) spectroscopy. MAT-PDMS and BIE were microencapsulated with urea-formaldehyde polymer. The surface and shell morphology of the microcapsules was investigated by scanning electron microscopy (SEM). Mean diameter and size distribution of the microcapsules could be controlled by agitation rate. A coating matrix formulation was prepared by sol-gel reaction of tetraethyl orthosilicate (TEOS) in the presence of a polysiloxane and by subsequent addition of an adhesion promoter. The formulation and microcapsules were mixed to give a self-healing coating formulation, which was then sprayed to surface of cellulose-fiber-reinforced-cement (CRC) board or mortar. Contact angle measurements showed that both the polymerized MAT-PDMS and the prepared coating matrix are hydrophobic, and the coating matrix has good wettability with MAT-PDMS. It was confirmed by optical microscopy and SEM that, when the self-healing coating is damaged, the healing agent is released from ruptured microcapsules and fills the damaged region. The self-healing coating was evaluated as protective coating for mortar, and it was demonstrated by water permeability and chloride ion penetration tests that our system has sunlight-induced self-healing capability. Our self-healing coating is the first example of capsule-type photoinduced self-healing system, and offers the advantages of catalyst-free, environmentally friendly, inexpensive, practical healing.

FABRICATION OF HOLLOW SILICA NANORODS USING NANOCRYSTALLINE CELLULOSE AS TEMPLATES

A simple approach to fabricate hollow silica nanorods is reported, using nanocrystalline cellulose (NCC) as templates. Uniform NCC with the length of ca. 100 nm and a diameter of ca. 10 nm were prepared by hydrolysis of microcrystalline cellulose (MCC) in strong sulfuric acid condition. NCC was used as a template to prepare a core-shell composite of silica and NCC. The sol-gel reaction of tetraethyl orthosilicate (TEOS) was employed to coat NCC with a nano thickness of silica in the presence of ammonia. Finally, hollow silica nanorods were obtained by calcination of the composite at 600°C to remove the organic cellulose template completely. The obtained hollow silica nanorods were found to have uniform size and shape: with a length of ca. 100 nm, an inner diameter close to the original diameter of NCC, and a thickness of around 10 to 15 nm. These results suggest that NCC is an excellent template for manufacturing nano hollow materials with uniform shape and size.