Periodic Mesoporous Organosilica Materials: Self‐Assembly of Carbamothioic Acid‐Bridged Organosilane Precursors

Abstract

A new series of carbamothioic acid-containing periodic mesoporous organosilica (PMO) materials has been synthesized by a direct cocondensation method, in which an organosilica precursor N,S-bis[3-(triethoxysilyl)propyl]carbamothioic acid (MI) is treated with tetraethyl orthosilicate (TEOS), and the nonionic surfactant Pluronic 123 (P123) is used as a template under acidic conditions in the presence of inorganic additives. Moreover, the synthesis of the PMO material consisting of the MI precursor without TEOS has been realized. These novel PMO materials have large surface areas, well-ordered mesoporous structures, hollow fiberlike morphologies, and thick walls. They are also structurally well-ordered with a high organosilica precursor content, and the carbamothioic acid groups are thermally stable up to 250 degrees C. Furthermore, the organosilica materials exhibit hydrothermal stability in basic solution.

Elevating enzyme activity through the immobilization of horseradish peroxidase onto periodic mesoporous organosilicas

“…In particular the content of N enhanced from 1.45% to 5.06% in the PMO sample MI10 to MI100. As reported previously, 23 the bridging carbamothioic acid groups were incorporated into the mesoporous framework; meanwhile the unhydrolyzed and uncondensed MI was dangling in the pore voids. Thus, the carbamothioic acid groups were not only bridged in the pore wall but also anchored in the pore void, 23 which is beneficial for enzyme immobilization by means of hydrogen bonding, hydrophobic interaction and so on.…”

“…The samples of the carbamothioic acid-bridged mesoporous organosilica MIn series had been characterized with low angle XRD, nitrogen adsorption-desorption and transmission electron microscopy methods previously in detail. 23 Table 2 illustrates the physicochemical properties of MIn, and a similar trend was also seen in these composites: when the percentage of MI precursor used in the mixture rose, the N contents of resulting sample increased accordingly. In particular the content of N enhanced from 1.45% to 5.06% in the PMO sample MI10 to MI100.…”

“…The PMO materials were synthesized according to literature, 23,24 for which the urea-bridged triethoxysilyl (abbreviated as A-I, its structure is shown in Scheme 1) and carbamothioic acid group bridged triethoxysilyl (abbreviated as M-I, its structure is also shown in Scheme 1) were prepared first. To synthesize the PMO, 2.0 g Pluronic P123 was dissolved in the solution of 80.0 g of 1 mol L À1 HCl and stirred for 24 h at room temperature, and then 9.36 g sodium chloride was added, followed by continual stirring for another 6 h. Afterward, the mixture of pre-mixed A-I or M-I and TEOS was added to the solution under vigorous stirring.…”

“…22 To date, however, the immobilization of HRP on PMO materials has not been examined yet, which spurs us to investigate systemically the immobilization and stability of this important enzyme on various functionalized mesoporous silica materials. Recently our group reported two long and flexible organic groups-carbamothioic acid group bridged triethoxysilyl and urea-bridged triethoxysilyl to synthesize the PMO samples named as MIn and AIn, 23,24 and here we try to immobilize HRP on them, assessing its activity and operational stability. The urea-bridged triethoxysilyl (abbreviated as A-I, Scheme 1) and carbamothioic acid group-bridged triethoxysilyl (abbreviated as M-I, Scheme 1) have similar molecular formulae but only one difference: N in A-I while S in M-I.…”

Multifunctional nanopatterned porous bismuth ferrite thin films

“…2 Beyond these attractive ferroic properties, BiFeO 3 also presents interesting optical properties and, consequently a great potential for applications in solid state devices that utilize heterojunction effects, and in photovoltaic and photocatalytic devices due to its small bandgap. [4][5][6][7][8][9][10] Among the most common processing methods to prepare ferroic thin films and nanostructures, chemical solution deposition as sol-gel is a low cost method that offers high versatility for the synthesis and development of a wide range of compositions, nanostructures and properties. 11 To fulfill the constant needs of the microelectronics industry of size and cost reduction, while enhancing performance, films with thickness below 100 nm and a well-patterned surface area are needed.…”