Kazuki Nakanishi

Sol-gel processes for fabricating oxides or metalloxane polymers with controlled porous structures have been reviewed. Gel materials having controlled macropores are synthesized by polymerization-induced phase separation and concurrent sol-gel transition in a variety of chemical compositions. Several variations of tailoring mesopore structures within the macroporous materials are introduced, which enable one to design hierarchically porous metal oxide and metalloxane polymer materials. Applicati

Phase separation which occurs in parallel to the hydrolysis and gelation of alkoxysilane solution containing poly(sodium styrenesulfonate) (NaPSS) has been investigated. Depending on the reaction conditions, gel morphologies such as isolated pores, particle aggregates, and interconnected continuous pores from 0.1 to 100 μm long have been observed. Time‐resolved light scattering of gelling solution suggested the occurrence of spinodal phase separation through the polymerization of silica and the

Porous polysilsesquioxane gels derived from sol-gel systems based on trifunctional silanes are reviewed. Although it is well known that trifunctional silanes possess inherent difficulties in forming homogeneous gels, increasing attention is being paid on these precursors and resultant porous polysilsesquioxanes because of hydrophobicity, functionality, and versatile mechanical properties. Much effort has been made to overcome the difficulties for homogeneous gelation, and a number of excellent p

We tested the hypothesis that intracoronary administration of L-arginine (L-Arg), the physiological nitric oxide (NO) precursor, during reperfusion would attenuate postischemic damage by L-Arg NO-pathway mechanisms. Open-chest, anesthetized dogs underwent 60 min of left anterior descending coronary arterial (LAD) occlusion followed by 270 min of reperfusion. Dogs received intracoronary 10 mM L-Arg (n = 9 dogs), intracoronary 10 mM D-arginine (D-Arg, n = 7), or saline vehicle (Veh, n = 10) in the

Monolithic ethane−silica gels with well-defined co-continuous macropores and highly ordered mesopores have been synthesized via a spontaneous route from silicon alkoxide with the aid of a structure-directing agent. While the macropores are formed by the concurrent phase separation and sol−gel transition induced by the polymerization reaction, the mesopores are templated by the self-organization of the structure-directing agent. Starting from a homogeneous mixture of the starting components, all

Abstract Phase separation and gelation behaviors have been studied for the acid-catalyzed, alkoxide-based silica systems containing poly(ethylene oxide) (PEO) with an average molecular weight of 100000. Gels with micrometer range interconnected porous morphology were obtained similarly to the systems containing other water-soluble polymers, in which the structure development by the spinodal decomposition and the gel forming process take place concurrently. In spite of the morphological similarit