Structural Characterization of Mesoporous Silica Nanofibers Synthesized Within Porous Alumina Membranes

Abstract

Mesoporous silica nanofibers were synthesized within the pores of the anodic aluminum oxide template using a simple sol–gel method. Transmission electron microscopy investigation indicated that the concentration of the structure-directing agent (EO20PO70EO20) had a significant impact on the mesostructure of mesoporous silica nanofibers. Samples with alignment of nanochannels along the axis of mesoporous silica nanofibers could be formed under the P123 concentration of 0.15 mg/mL. When the P123 concentration increased to 0.3 mg/mL, samples with a circular lamellar mesostructure could be obtained. The mechanism for the effect of the P123 concentration on the mesostructure of mesoporous silica nanofibres was proposed and discussed.

Engineering and optimization of nano- and mesoporous silica fibers using sol–gel and electrospinning techniques for sorption of heavy metal ions

“…Traditional approaches for preparation of MSFs mainly include acid hydrolyzation [11,12], mechanical drawing [13,14], and template self-assembly [15]. The acidic hydrolyzing method has advantages of size and morphology control of the products; however, it is time consuming and technically demanding.…”

“…In the template self-assembly process, pores in templates act as a microreaction vessel, whose shapes and sizes decide the morphology, scale, and to a certain degree influence the mesostructure of the MSFs [15][16][17], and long fibers are hard to be obtained due to restriction of the template thickness. Besides, sacrifice of the template will further increase the cost.…”

Size-selective separations of biological macromolecules on mesocylinder silica arrays

“…To improve nanoporous membranes synthesized using AAM as hard templates [19][20][21][22][23][24][25][26][27][28], the following problems on chemical and mechanical stability must be addressed: (1) synthesis of robust, tubular structures into the entire AAM nanochannels, (2) formation of unconnected pores and irregular shapes due to the detachment of mesoporous silica NTs from AAM walls, (3) creation of air gaps within the shrinkage of the mesoporous silica upon high-temperature calcination of soft templates (see Supporting Information S1), and (4) low-term chemical stability of AAM within the separation reuse-cycles. Such manufacturing defects in mesoporous silica NT arrays hybrid AAM limit the long-term storage stability of NTs inside AAM (even for a month) and reduce the potential of NT filtration systems to control the filtration rates and diffusivity of biological macromolecules.…”

“…Since the discovery by Martin [17] of 1D nanochannels inside anodic alumina membrane (AAM), engineered control over regularly spaced pores and uniformly shaped dimensions of nanochannels has led to widespread advancements in materials science [14,18,19]. In particular, substantial efforts have been devoted to the fabrication of 1D or 2D hexagonally ordered or stacked doughnut (circular) silica mesostructures inside the columnar pores of AAM nanochannels by template-guided syntheses; these have been done using amphiphiles that differ in character and structure over a wide range of synthesis conditions [20][21][22][23][24][25][26][27][28]. These reliable methods have been widely used to fabricate a range of 1 and 2D mesostructured silica [20][21][22][23][24][25][26][27][28].…”

“…In particular, substantial efforts have been devoted to the fabrication of 1D or 2D hexagonally ordered or stacked doughnut (circular) silica mesostructures inside the columnar pores of AAM nanochannels by template-guided syntheses; these have been done using amphiphiles that differ in character and structure over a wide range of synthesis conditions [20][21][22][23][24][25][26][27][28]. These reliable methods have been widely used to fabricate a range of 1 and 2D mesostructured silica [20][21][22][23][24][25][26][27][28]. Silica mesostructures feature uniform pores with diameters ranging from a few nanometers to tens of nanometers; they are thermally (i.e., under high-temperature ≥800 • C) and chemically (i.e., in organic and inorganic solutions) stable.…”