TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preparation: (II) and (III) are combined in aqueous or polar solvent and, after polymerization, the solvent is evaporated to form a transparent, mesostructured material with a uniform characteristic order length scale (of at least 50 Angstrom ). This material has the following characteristics: (i) is crack-free; (ii) has large d spacing (in X-ray diffraction; at least 60 Angstrom ) and thick inorganic walls (at least 30 Angstrom ); (iii) is in the form of fibers, thin films or monoliths; (iv) has a two-dimensional hexagonal, cubic or lamellar mesostructure. The pore size and wall thickness may be increased by adding an organic co-solvent to (II), and these effects, also increased thermal stability, can be achieved by heat treatment. Particularly, after polymerization, the polymer is removed (by calcining or solvent extraction) to produce a heat-stable multivalent metal oxide material of high surface area. This material has porosity at least 40% and surface area at least 100 m2 g-1, with pore size at least 30 Angstrom and dielectric constant 2-2.5. Particularly (III) is added as a sol gel to (II) dissolved in aqueous solution of inorganic salt. The product is polymerized and calcined to produce 'coral-like' (B).Preferred materials: (III) is a compound that, after calcination, forms an oxide of titanium, zirconium, niobium, tantalum, silicon (most preferred), wolfram, tin, hafnium or the mixed oxides SiAlOx (x = 3.5 or 5.5), AlTiO5, ZrTiO4 or SiTiO4.    TECHNOLOGY FOCUS - POLYMERS - (II) is a triblock copolymer, especially poly(ethylene oxide)-poly(propylene or butylene oxide)-poly(ethylene oxide); a diblock polymer; a reverse triblock polymer or a (reverse) star diblock polymer. EXAMPLE - A solution of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymer (1 g) in ethanol (10 ml) was treated with zirconium tetrachloride (0.01 moles), with stirring. The sol formed was allowed to gel in an open dish at 40-60degreesC, then calcined at 400degreesC for 5 hours to remove the polymer. The product was a zirconium dioxide material with d spacing 106 Angstrom ; wall thickness 65 Angstrom ; nanocrystal size 15 Angstrom ; pore size 58 Angstrom ; BET surface area 150 m2 g-1 and porosity 0.43. It was a dielectric.