Ordered Mesoporous Silicas and Carbons with Large Accessible Pores Templated from Amphiphilic Diblock Copolymer Poly(ethylene oxide)-b-polystyrene

Abstract

Highly ordered mesoporous carbons and silicas with ultralarge accessible pores have been successfully synthesized by using laboratory-made poly(ethylene oxide)-b-polystyrene (PEO-b-PS) diblock copolymers as templates via the evaporation-induced self-assembly (EISA) approach. Resols and tetraethyl orthosilicate (TEOS) serve as carbon and silica precursors, respectively. Small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) measurements show that the mesoporous carbons (denoted as C-FDU-18) possess face centered cubic closed-packing (fcc) mesostructure (Fm3m) with large-domain ordering. N2 sorption isotherms reveal a large mesopore at the mean value of 22.6 nm with a narrow pore-size distribution. Mesoporous silicas (Si-FDU-18) also display a highly ordered fcc closed-packing mesostructure with an ultralarge unit cell (a = 54.6 nm). A hydrothermal recrystallization was introduced for the first time to produce micropores in thick silica walls (approximately 7.7 nm) and thus to generate ultralarge accessible mesopores (30.8 nm). Notably, the amphiphilic diblock copolymer with high molecular weight (PEO125-PS230, 29700 g mol-1) in this report was prepared via a simple method of atom transfer radical polymerization (ATRP). It can be easily available for chemists even without any experience in polymer synthesis.

Improved conductivity in dye-sensitised solar cells through block-copolymer confined TiO2crystallisation

“…The for their thickness unusual high efficiencies of the solid-state DSCs also prove that the titania network, though micellar, is well interconnected 37 and allows sufficient pore infiltration with a solid-state hole conductor.…”

Fabrication and Characterization of Inorganic Silver and Palladium Nanostructures within Hexagonal Cylindrical Channels of Mesoporous Carbon

“…The phenolic was synthesized through a condensation reaction with H 2 SO 4 , producing a material with an average molecular weight (M n = 500) similar to those described previously [6], EtOH (95%) and tetrahydrofuran (THF, >99%) were purchased from ECHO (Kaohsiung, Taiwan). Diblock copolymers were prepared through the ring-opening polymerization (ROP) of ε-CL in the presence of PEO 114 and Sn(Oct) 2 . The reaction mixtures were prepared by introducing a desired volume of ε-CL monomer into a silanized flask containing a pre-weighed amount of PEO 114 under a N 2 atmosphere.…”

“…Evaporation-induced self-assembly (EISA) has been developed aggressively as a strategy for the fabrication of mesoporous nanostructures because of its broad applicability to soft templating using various block copolymer templates [1][2][3][4][5][6][7][8][9][10][11][12]. Prior to its development, the pore sizes of mesoporous carbons were limited to approximately 5-10 nm as a result of the need for copolymer templates of low molecular weight [13,14].…”

“…Prior to its development, the pore sizes of mesoporous carbons were limited to approximately 5-10 nm as a result of the need for copolymer templates of low molecular weight [13,14]. The EISA method made it feasible to regulate pore structures and pore sizes and allowed the preparation of various mesoporous materials from water-insoluble systems, including mesoporous silicas [2,7,8,10,[15][16][17][18], mesoporous resins [3,6,9,11], mesoporous TiO 2 [19][20][21], and mesoporous carbons [2,4,12,16,[22][23][24]. The typical procedure used to prepare ordered mesoporous carbons, so-called "template synthesis" [25][26][27][28][29][30], involves the use of mesoporous silicas as hard templates, impregnation of carbon precursors into their mesochannels, carbonization under an inert gas, and finally dissolving the hard template of the "ordered mesoporous silica" through etching in HF (aq) .…”

Mechanochemical synthesis of carbon-based nanocomposites for supercapacitors

“…Activated carbons can be derived from natural materials (plant shells [17], peel [18,19], etc.) or synthetic materials (polymers) by carbonization in inert atmosphere followed by activation with KOH/NaOH, K 2 CO 3 , ZnCl 2 , H 3 PO 4 , CO 2 or steam [20][21][22][23][24][25][26][27][28]. Although the activation after carbonization increases the S s of the carbons, it leads to widening of the pore size distribution and lowering of the product yield.…”