Groups Of PAA Research Articles

Preparation and properties of polyimide/graphene oxide nanocomposite films with Mg ion crosslinker

Polyimide(PI)/graphene oxide(GO) nanocomposite films were prepared by chemical cross-linking using small amounts of divalent Mg ions. The PI/GO nanocomposites showed enhanced tensile properties compared to pristine PI due to the presence of exfoliated GO in the PI matrix as well as crosslinking between poly(amic acid) (PAA), which is a precursor of PI, and GO by Mg ions. The hydrogen bonds between PAA and GO suppressed the phase separation between PI and GO, and small amounts of Mg ions can bond between the oxygen functional groups and carboxylate groups of GO and PAA.

Effects of addition of anionic and cationic surfactants to poly(N-isopropylacrylamide) microgels with and without acrylic acid groups

The interaction of the anionic surfactant sodium dodecyl sulfate (SDS) and the cationic surfactant hexadecyl trimethyl ammonium bromide with poly(N-isopropylacrylamide) (PNIPAAM) microgels with and without poly(acrylic acid) (PAA) was investigated by means of dynamic light scattering (DLS), zeta potential, and turbidimetry measurements. The DLS results show that the PNIPAAM microgels with PAA will contract when an anionic or cationic surfactant is added to the suspension, while the PNIPAAM microgels without PAA expand in the presence of an ionic surfactant. A collapse of the PNIPAAM microgels is observed when the temperature is increased. From the zeta potential measurements, it is observed that the charge density of PNIPAAM microgels in the presence of an ionic surfactant is significantly affected by temperature and the attachment of the negatively charged PAA groups. The turbidity measurements clearly indicate that the interaction between PNIPAAM and SDS is more pronounced than that of the cationic surfactant.

Poly(amic acid)‐Supported Heterogeneous Titanium‐Based Ziegler‐Natta Catalyst for Ethylene Polymerization in a Slurry Process

AbstractThe synthesis of a poly(amic acid) (PAA)‐supported Ziegler–Natta catalyst (PAA‐TiCl4) by the reaction of PAA and titanium tetrachloride (TiCl4) is reported. For ethylene polymerization, three catalysts were synthesized by varying the TiCl4/PAA weight ratio in a hexane medium. The resulting catalysts were characterized by Fourier‐transformed infrared (FT‐IR), ultraviolet (UV), scanning electron microscopy and energy dispersive x‐ray detector (SEM‐EDX), and x‐ray diffraction analysis (XRD). The acidity of the catalysts in an acetone/water solution was measured by a pH meter. Thermogravimetric analysis reveals that catalysts are stable up to 110–125°C. Because of their higher degree of thermal stability, these catalysts may potentially be used as a support in a conventional Ziegler–Natta catalyst for ethylene polymerization. Furthermore, because of the extensive reaction between the functional groups of PAA and TiCl4, the chain structure of the PAA was destroyed. The newly synthesized catalysts showed good storability, and the overall catalytic productivity is 4921 g PE/g Ti/h. A catalyst with titanium incorporation corresponding to 2.8 wt% showed the maximum activity. The productivity of the catalysts also depended on the titanium concentration in the polymer matrix. These catalysts are found to retain their catalytic activity for a long time (∼90 days), and a mild reaction condition is required for catalysis. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 32: E119–E130, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20276

Effects of Concentration and Temperature on the Dynamic Behavior of PAA-g-PEO Aqueous Solutions with Different Counterion Species: A Dielectric Spectroscopy Study

Dielectric properties of PAA-g-PEO-7% solutions with different counterions were measured as a function of concentration and temperature over a frequency range of 40 Hz to 110 MHz. After the contribution of electrode polarization effects was subtracted, the dielectric spectra of PAA-g-PEO-7% solutions showed three relaxation processes in the experimental frequency range, named low-, mid-, and high-frequency relaxation. The observed three relaxations were strictly analyzed by using the Cole-Cole relaxation function, and the dielectric parameters (dielectric increment Δε and the relaxation time τ) were obtained. The scaling relation of dielectric increment and relaxation time of high frequency with concentration C(p) were obtained and compared with the predictions of scaling theories. The information on the dynamics and microstructure of PAA-g-PEO-7% was obtained. Using different counterion species, the mid- and high-frequency relaxation mechanisms were attributed to the fluctuation of condensed counterions and free counterions, respectively, and the low-frequency relaxation was considered to be caused by the interface polarization of a complex formed by the hydrogen bonding between carboxylic group of PAA and ether oxygen on the side-chain PEO. In addition, by means of Eyring equation, the thermodynamic parameters, enthalpy change ΔH and entropy change ΔS, of the three relaxations were calculated from the relaxation time and discussed from the microscopic thermodynamical view.

Structural analysis of microbial poly(ɛ-L-lysine)/poly(acrylic acid) complex by FT-IR, DSC, and solid-state 13C and 15N NMR

Interpolymer complexes of microbial poly(ɛ-L-lysine) (ɛ-PL) and poly(acrylic acid) (PAA) were studied by Fourier transform infrared spectroscopy, differential scanning calorimetry and solid-state 13C and 15N nuclear magnetic resonance (NMR) experiments. These measurements suggested the poly-ionic complex formation between ɛ-PL and PAA, ɛ-PL-H3N+···−OOC-PAA. By analyzing 13C NMR spectra of the complex, we concluded that there exist three forms of the carboxyl group of PAA, namely: (1) the ionized form, interpolymer ion-complex between ɛ-PL and PAA, (2) the dimeric form, intrapolymer hydrogen bonding among PAA molecules and (3) the free form, no particular form of hydrogen bonding.

Fabrication of TiO 2-coated magnetic nanoparticles on functionalized multi-walled carbon nanotubes and their photocatalytic activity

A novel magnetic photocatalyst with a hybrid nanostructure consisting of multi-walled carbon nanotubes (MWCNTs), Fe 3O 4 nanoparticles and a TiO 2 layer was prepared. First of all, poly(acrylic acid) (PAA) was grafted onto the surface of MWCNTs by in situ polymerization. Fe 3O 4 nanoparticles were then anchored on PAA chains through amidation reaction between the amino groups on the surface of the Fe 3O 4 nanoparticles and the carboxyl groups of PAA. Finally, a TiO 2 layer was coated onto the surface of the modified MWCNTs through hydrogen bonding interactions between the hydroxyl groups on the surface of titanium dioxide and the carboxyl groups of PAA or the amino groups of Fe 3O 4. The morphology and structure of the intermediate and final hybrids were investigated by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The magnetism of the product was characterized using a vibrating sample magnetometer. It was shown that the TiO 2 decoration shifts the absorbance spectrum of the hybrid to the entire UV–vis region. The photo-catalytic function of the MWCNT/Fe 3O 4/TiO 2 hybrids was validated for phenol degradation under irradiation of UV–vis light.

Systematic comparison of the size, surface characteristics and colloidal stability of zero valent iron nanoparticles pre- and post-grafted with common polymers

This study systematically examines the effect of four common polymers on the size, surface chemistry, colloidal stability, and sedimentation behaviour of nanoparticles of zero valent iron (NZVI). The mean diameters of NZVI ranged from 5 to 189 nm, depending on the synthesis conditions. The influence of the pre- or post-grafting of the polymers on the above parameters was also investigated. The four polymers are carboxymethyl cellulose (CMC), poly(styrenesulfonate) (PSS), poly(acrylic acid) (PAA) and polyacrylamide (PAM). The molecular weight of these polymers range over three orders of magnitude, from 1.8 × 103 to 5000 × 103 g mol −1 and they are all negatively charged with the exception of the non-ionic PAM. All NZVI samples were synthesized by sodium borohydride reduction of ferrous sulfate solutions. For pre-grafting, the NZVI was synthesized in the presence of the different polymers and identical synthesis conditions were maintained which allowed for an unbiased and direct comparison of the characteristics of the different particles. ATR-FTIR analyses revealed that both pre- and post-grafted polymers were bound to the iron nanoparticle surface with polar bonds between carboxylate groups of CMC and PAA, sulfonate groups of PSS, and with hydrogen bonds with the amine groups of the non-ionic PAM. TEM images and nanoparticle tracking analysis revealed that iron nanoparticles synthesised in the presence of the polymers were larger in diameter, with TEM mean diameters ranging from 84.5 to 189 nm, than the bare-NZVI (59.1 nm), when synthesized with the same initial Fe 2+ concentration. Altering the CMC or Fe 2+ concentration during synthesis allowed synthesis of relatively monodisperse, colloidally stabilized CMC-NZVI with defined average diameters ranging from 5 nm to 129 nm. XPS studies indicated that all pre-grafted polymer-stabilized NZVI had a polymer coating covering a core–shell structure with a shell of iron oxide–hydroxides and a core of Fe 0. Pre-grafted CMC was found to be the most efficient in colloidally stabilizing NZVI. Sedimentation tests demonstrated that after 60 min pre-grafted CMC-NZVI were slightly more stable than pre-grafted PAA-NZVI, but at least two-times more stable than pre-grafted PSS- or PAM-NZVI and 13 times more stable than bare-NZVI. The colloidal stability of all post-grafted NZVI was lower than the corresponding pre-grafted particles by 1.3 to 6 times, with the exception of PSS. The nature of polymer–Fe interactions were further explored by ATR-FTIR spectra of pre- and post-grafted particles. These results highlight the relevance of the extent and the nature of the polymer–Fe interactions during synthesis of polymer-stabilized NZVI.

Thermal and microbial degradation of alginate-based superabsorbent polymer

In this study, an alginate-based superabsorbent polymer (SAP), alginate- graft-poly[acrylamide- co-(itaconic acid)- g-(acrylic acid)] or Alg- g-P(AM- co-IA- g-AA), was prepared to examine its thermal and microbial degradation properties through Thermogravimetric Analysis (TGA), and soil supernatant test (with and without added nutrient) and soil burial test, respectively. The TGA thermogram of the SAP showed three degradation steps. The first degradation step was due to the thermal degradation of alginate and decomposition of the functional groups of PAM, PIA and PAA; whereas the second degradation step occurred as a result of the decomposition of PAM, PAA and PIA chains. Further decomposition of PIA contributed to the third degradation step. Among all the soil samples [tropical forest soil (TF), former tin mine lake soil (TM), peanut farm soil (PF), indigenous microorganism soil from an organic vegetable farm (OF), and oil palm plantation soil (OP)] tested, OF soil degraded the polymer sample most effectively, with the highest weight loss of 82.6% (with added nutrient) and 82.8% (without added nutrient) in soil supernatant tests, and 63.5% in soil burial test. Morphological observation under an Illuminated Stereo Microscope showed some holes and weak topographical spots on the surface of the polymer material after it had been incubated in OF solution for 40 days. Meanwhile, the intrinsic viscosities, [ η], of NaAlg and the Alg-based SAP solutions were 2.62 and 2.75 respectively.

Bioinspired Crystallization of CaCO3 Coatings on Electrospun Cellulose Acetate Fiber Scaffolds and Corresponding CaCO3 Microtube Networks

This article describes the mineralization behavior of CaCO(3) crystals on electrospun cellulose acetate (CA) fibers by using poly(acrylic acid) (PAA) as a crystal growth modifier and further templating synthesis of CaCO(3) microtubes. Calcite film coatings composed of nanoneedles can form on the surfaces of CA fibers while maintaining the fibrous and macroporous structures if the concentration of PAA is in a suitable range. In the presence of a suitable concentration of PAA, the acidic PAA molecules will first adsorb onto the surface of CA fibers by the interaction between the OH moieties of CA and the carboxylic groups of PAA, and then the redundant carboxylic groups of PAA can ionically bind Ca(2+) ions on the surfaces of CA fibers, resulting in the local supersaturation of Ca(2+) ions on and near the fiber surface, which can induce the nucleation of CaCO(3) on the CA fibers instead of in bulk solution. Calcite microtube networks on the macroscale can be prepared by the removal of CA fibers after the CA@CaCO(3) composite is treated with acetone. When the CA fiber scaffold is immersed in CaCl(2) solution with an extended incubation time, the first deposited calcite coatings can act as secondary substrate, leading to the formation of smaller calcite mesocrystal fibers. The present work proves that inorganic crystal growth can occur even at an organic interface without the need for commensurability between the lattices of the organic and inorganic counterparts.

Introducing surface-tethered poly(acrylic acid) brushes as 3D functional thin film for biosensing applications

Carboxyl groups of surface-tethered poly(acrylic acid) (PAA) brushes should be able to serve as versatile moieties for a wide range of chemical modifications, including an attachment of bioactive species that can act as sensing probes for biosensors. In this research, poly(tert-butyl acrylate) (Pt-BA) brushes were prepared by surface-initiated atom transfer radical polymerization of tert-butyl acrylate. PAA brushes were then obtained after removal of the tert-butyl groups from the Pt-BA brushes by acid hydrolysis. The carboxyl group density of the PAA brushes can be varied as a function of chain length or molecular weight. The reactivity of the carboxyl groups of PAA brushes towards the immobilization of biotin, a frequently used model bioactive probe in biosensing applications, was evaluated. Qualitative determination of streptavidin (SA) binding to the biotin-attached PAA brushes was verified by fluorescence microscopy. The efficiency of the PAA brushes to act as a three dimensional (3D) precursor layer for biosensing applications was further demonstrated using surface plasmon resonance (SPR), where the biotin-attached PAA brushes showed an enhanced signal for the biospecific binding of SA in comparison with a self-assembled monolayer (SAM) of a carboxyl-terminated alkanethiol, used as a model two-dimensional (2D) conventional precursor layer. The PAA brushes showed very low non-specific interactions with two other tested proteins of a similar pI but different sizes. This desirable feature should be highly beneficial for the development of biosensors.

Effective PEGylation of Iron Oxide Nanoparticles for High Performance In Vivo Cancer Imaging

AbstractA practical and effective strategy for synthesizing PEGylated superparamagnetic iron oxide nanoparticles (SPIONs) is established. In this strategy, poly(acrylic acid) (PAA) is combined with SPIONs via multiple coordination between the carboxylic groups of PAA and SPIONs, which introduces abundant carboxylic groups, then, α,ω‐diamino PEG is linked to SPIONs via the amidation of the carboxylic groups. The synthesized PEGylated SPIONs exhibit no cytotoxicity and high resistance to phagocytosis by macrophages in vitro as well as low uptake by the liver and spleen in vivo, which makes the SPIONs highly efficient in tumor imaging by magnetic resonance imaging (MRI) at a relatively low dose of SPIONs. These outstanding properties are largely due to the significant shielding effect of the dense PEG coating as well as the net neutral surface of the PEGylated SPIONs in physiological conditions. In summary, the PEGylated SPIONs prepared by this strategy exhibit great application potential in tumor imaging as MRI contrast agents targeting through enhanced permeability and retention (EPR) effect.

Controllable disintegration of temperature-responsive self-assembled multilayer film based on polybetaine

A layer-by-layer (LbL) self-assembly technique was used to construct temperature-responsive multilayer films of polybetaine poly-3-dimethyl(methacryloyloxyethyl) ammonium propane sulfonate (PDMAPS) and poly(acrylic acid) (PAA). The assembly and disintegration behaviors of PDMAPS/PAA multilayer films were investigated by quartz crystal microbalance (QCM) and atomic force microscopy (AFM). The results indicated that the assembly behaviors of PDMAPS/PAA multilayer films could be well regulated by the pH and temperature of dipping solutions. The disintegration of PDMAPS/PAA multilayer films could be well controlled by varying the disintegration temperature ( T d) and the pH of buffer solution. The critical disintegration temperature ( T cd) decreased with increasing pH of buffer solution used. The ionization of carboxylic acid groups (COOH) of PAA and the breakage of intra-chain associations of PDMAPS in multilayer films are two main reasons for the film disintegration. Based on the controllable disintegration of the PDMAPS/PAA multilayer, free-standing multilayer films were successfully prepared by LbL self-assembly of poly(4-vinylpyridiniomethanecarboxylate) (PVPMC) and PAA using PDMAPS/PAA as a sacrificial sublayer.

Environmentally Responsive Particles: From Superhydrophobic Particle Films to Water-Dispersible Microspheres

We describe the preparation, by precipitation copolymerization, of multifunctional divinylbenzene-co-pentafluorostyrene microspheres able to produce superhydrophobic surfaces or disperse in aqueous media upon annealing either in air or water, respectively. For that purpose, an amphiphilic block copolymer, polystyrene-b-poly(acrylic acid), was introduced in the initial feed composed of divinylbenzene and 2,3,4,5,6-pentafluorostyrene. As a result, fluorinated particles were obtained in which the diblock copolymer was encapsulated during the polymerization step. Upon annealing in dry air, the particles are completely hydrophobic and form superhydrophobic surfaces. On the contrary, annealing in water induces the reorientation of the PAA groups toward the particle interface, thus the particles can be dispersed in aqueous media. In addition, the presence of carboxylic acid groups at the particle interface permits us to switch the surface charge between negative and neutral depending on the environmental pH.

Hot Melt Reactive Extrusion of Chitosan with Poly(acrylic acid)

The hot melt reactive extrusion of blends of chitosan and poly(acrylic acid) (PAA) was carried out without any process additives such as organic solvent or plasticizer. The maximum amount of chitosan in the blend during the extrusion process was kept at 40 wt%, since the melt viscosity of a system containing 50 wt% of chitosan exceeded the torque limitation of the equipment. The carboxylic groups of PAA interacted with the amine groups of chitosan during the melt process, and the system exhibited good melt flow. The interactions between these two polymers were explained by investigating the results obtained by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The thermal transition behavior of PAA was altered with a decrease of more than 10°C in the peak melting point after extrusion. The infrared (IR) spectroscopic data confirmed the existence of a complex formation and possible hydrogen bonding between chitosan and PAA during the melt process. Scanning electron microscopy (SEM) micrographs indicated that chitosan was well-dispersed in the PAA blends up to 30 wt% chitosan, with no indication of loose particles or other disruptions on the upper and lower fractured faces. This smooth interface might have been caused by the interaction between amide bonds of chitosan and carboxylic groups of PAA.

Decoration of Fe3O4 nanoparticles on the surface of poly(acrylic acid) functionalized multi‐walled carbon nanotubes by covalent bonding

AbstractFe3O4 nanoparticles were indirectly implanted onto functionalized multi‐walled carbon nanotubes (MWCNTs) leading to a nanocomposite with stronger magnetic performance. Poly(acrylic acid) (PAA) oligomer was first reacted with hydroxyl‐functionalized MWCNTs (MWCNTs‐OH) forming PAA‐grafted MWCNTs (PAA‐g‐MWCNTs). Subsequently, Fe3O4 nanoparticles were attached onto the surface of PAA‐g‐MWCNTs through an amidation reaction between the amino groups on the surface of Fe3O4 nanoparticles and the carboxyl groups of PAA. Fourier transform infrared spectra confirmed that the Fe3O4 nanoparticles and PAA‐g‐MWCNTs were indeed chemically linked. The morphology of the nanocomposites was characterized using transmission electron microscope (TEM). The surface and bulk structure of the nanocomposites were examined using X‐ray diffraction, X‐ray photoelectron spectrometer (XPS), and thermogravimetric analysis (TGA). The magnetic performance was characterized by vibrating sample magnetometer (VSM) and the magnetic saturation value of the magnetic nanocomposites was 47 emu g−1. The resulting products could be separated from deionized water under an external magnetic field within about 15 s. Finally, the magnetorheological (MR) performances of the synthesized magnetic nanocomposites and pure Fe3O4 nanoparticles were examined using a rotational rheometer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

Lipophilic carbon nanotubes and their phase-separation in SBS

Highly lipophilic multi-walled carbon nanotubes (MWNTs) were successfully prepared by grafting PAA onto the surface of MWNT, followed by replacing carboxyl groups of PAA with octadecylamine through amidation. The improved dispersion of functionalized MWNTs and enhanced mechanical properties of nanotube/SBS composites were observed. The composite thin films with different MWNT loading prepared via spin-coating were investigated by means of atomic force microscopy (AFM) in order to study the dispersion of MWNTs in the polymer matrix. The evolution of MWNT/SBS composite thin film surface morphology with the variation of MWNT concentration is presented. When the MWNT concentration is lower than 1 wt%, the composite thin film is homogeneous. With increase of MWNT concentration, phase separation can be clearly observed. It is found that the state of aggregation of MWNTs in the polymer matrix determine the mechanical properties of the composites.

Unusual Phase Behavior of the Mixture of Poly(acrylic acid) and Poly(diallyldimethylammonium chloride) in Acidic Media

A new type of temperature-sensitive polymer systems based on mixtures of poly(acrylic acid) (PAA) and poly(diallyldimethylammonium chloride) (PDADMAC) in strongly acidic aqueous medium is described. The mixtures exhibit reversible separation into two liquid phases upon a decrease in temperature. The phase separation is induced by the intermolecular binding between PAA and PDADMAC due to ion−dipole interactions between protonated carboxylic groups of PAA and quaternary nitrogen atoms of PDADMAC. Molecular and hydrodynamic characteristics of the interpolymer complexes are probed by static and dynamic light scattering.

Interaction between Poly(acrylic acid) and Phospholipid Vesicles: Effect of pH, Concentration, and Molecular Weight

Interactions between phospholipid vesicles and poly(acrylic acid) (PAA) are of fundamental importance for pH-sensitive delivery systems in pharmaceutical applications. In this study, we investigated the behavior of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) at varied concentrations of PAA with low and high molecular weights. Differential scanning calorimetry and fluorescence microscopy experiments suggested that hydrogen bonding between the carboxyl group of PAA and the phosphodiester group of the lipid is the main driving force for association under acidic conditions. Complexation between DPPC and PAA depends on the PAA molecular weight and concentration. At high enough concentrations of the large molecular weight PAA, the polymer can completely disrupt the bilayers of DPPC. For the small molecular weight PAA, in contrast, the complexation leads to vesicle aggregation without destroying the bilayers. The difference in complex structure was detected by SEM and a UV-visible spectrophotometer. At alkaline pH, complexation did not occur because of strong dissociation of PAA.

Iron-Functionalized Membranes for Nanoparticle Synthesis and Reactions

Membrane-based separation processes have been used extensively for drinking water purification, wastewater treatment, and numerous other applications. More recent developments in membrane functionalization have made the use of membrane science important in diverse fields, from tunable separations to catalysis. The focus of this work is to create a common membrane platform for the incorporation of technologies capable of degrading target pollutants. Functionalized membranes capable of metal capture were created using water-based and solvent-based acrylic acid polymerization to synthesize poly(acrylic acid) (PAA) within poly(vinylidene fluoride) (PVDF) membrane pores. The COO− groups of PAA were used to capture Fe(II), which was then either reduced and doped with Pd to form Fe/Pd nanoparticles or used as-is for free radical generation with hydrogen peroxide. Fe/Pd nanoparticles were synthesized within the pores of a PAA/PVDF membrane functionalized via aqueous (green) chemistry and used to dechlorinate trichloroethylene (TCE) and 2,2′-dichlorobiphenyl (DiCB). A PAA/PVDF membrane containing immobilized Fe(III) was used to obtain controlled free radical generation and target organic (pentachlorophenol) degradation within the membrane pore under convective flow conditions.

Polyelectrolyte multilayer film-assisted formation of zero-valent iron nanoparticles onto polymer nanofibrous mats

A facile approach that combines the electrospinning technique and layer-by-layer (LbL) assembly method has been developed to synthesize and immobilize zero-valent iron nanoparticles (ZVI NPs) onto the surface of nanofibers for potential environmental applications. In this approach, negatively charged cellulose acetate (CA) nanofibers fabricated by electrospinning CA solution were modified with bilayers composed of positively charged poly(diallyl-dimethyl-ammoniumchloride) (PDADMAC) and negatively charged poly(acrylic acid) (PAA) through electrostatic LbL assembly approach to form composite nanofibrous mats. The composite nanofibrous mats were immersed into the ferrous iron solution to allow Fe(II) ions to complex with the free carboxyl groups of PAA, and then ZVI NPs were immobilized onto the composite nanofibrous mats instantly by reducing the ferrous cations. Combined scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and thermogravimetry analysis demonstrated that the ZVI NPs are successfully synthesized and uniformly distributed into the polyelectrolyte (PE) multilayer films assembled onto the CA nanofibers. The present approach to synthesis ZVI NPs opens a new avenue to fabricating various materials with high surface area for environmental, catalytic, and sensing applications.