Porous Siloxane–Organic Hybrid with Ultrahigh Surface Area through Simultaneous Polymerization–Destruction of Functionalized Cubic Siloxane Cages

Abstract

A novel hierarchically porous, hyper-cross-linked siloxane-organic hybrid (PSN-5) has been synthesized by Friedel-Crafts self-condensation of benzyl chloride-terminated double-four-ring cubic siloxane cages as a singular molecular precursor. Simultaneous polymerization of the organic functional groups and destruction of the siloxane cages during synthesis yielded PSN-5, which has an ultrahigh BET surface area (∼2500 m(2) g(-1)) and large pore volume (∼3.3 cm(3) g(-1)) that to our knowledge are the highest values reported for siloxane-based materials. PSN-5 also shows a high H(2) uptake of 1.25 wt % at 77 K and 760 Torr.

Hyperbranched Polysiloxanes Based on Polyhedral Oligomeric Silsesquioxane Cages with Ultra-High Molecular Weight and Structural Tuneability

“…The unit cell of crystal 1 belongs to the triclinic group, and there is one POSS molecule for each unit cell (See Table S2 for unit cell parameters). The relative 1 H-and 29 Si-NMR spectra ( Figures S1 and S2) confirmed the structure. As shown in Figure 2, the full preservation of the POSS cage is consistent with the benign nature of the B(C 6 F 5 ) 3 catalyst towards the Si-O bonds, and the Si-O bonds are usually uninterrupted during the Pier-Rubinsztajn reaction as shown by Brook et al [39].…”

“…The POSS cages with two connecting points can be incorporated into linear polymer backbones, and they can be attached sidelong of linear polymers if only one connecting point is present [23][24][25][26][27][28]. POSS cages with multiple connecting points usually lead to cross-linked polymers, and the special geometry of POSSs can make the polymers possess interesting permanent porosity [29][30][31].…”

Microporous inorganic/organic hybrids via oxysilylation of a cubic symmetry nanobuilding block [(HMe₂SiOSiO_1.5)₈] with R<i>_x</i>Si(OEt)_4&minus;<i>_x</i>

“…Silsesquioxane based high SSA materials have been synthesized by FriedelCrafts, 43)45) cross-coupling, 41),46) 48) thiol-ene, 49) radical polymerization, 50) polyesters/polyimides, 51),52) and hydrosilylation. 42)53) The best of these materials made by FriedelCrafts reaction was reported by Chaikittisilp et al, in which they have achieved 2500 m 2 /g.…”

“…42)53) The best of these materials made by FriedelCrafts reaction was reported by Chaikittisilp et al, in which they have achieved 2500 m 2 /g. 43) However most methods are limited due to their multistep reactions, and use of expensive or large amounts of catalyst.…”

Graft polymerization of acrylamide monomers from polysilsesquioxane containing xanthate groups

“…[1][2][3][4][5][6][7][8][9][10][11][12] The graft polymerization from the silsesquioxane backbone is an effective method for transforming the silsesquioxanes into practical and useful materials. [13][14][15][16][17][18][19][20] Grafted silsesquioxanes are expected to show functions based on the incorporated polymeric components without losing the essential properties of the inorganic polysiloxane structure, such as durability against heat and weatherability. With the regard to this expectation, we also tried to develop new multifunctional hybrid materials using acrylamide monomers by the graft polymerizations from polysilsesquioxane (PSQ).…”