NOVELTY - A mesoporous carbon film comprises a film of carbon defining an open network of interconnected primary pores arrayed in a uniform, random manner throughout the film, the pores having an average pore diameter of 2-3 nm, where the diameters of the pores have a substantially unimodal pore diameter distribution, and not more than 20% of the pores have a diameter of less than about 1 nm.    USE - The invention is used for, e.g. ultrafiltration membrane, gas separation membrane, catalytic membrane, or hydrogen storage medium (claimed).    ADVANTAGE - The invention has low percentage of pores with diameters of less than 1 nm, and having an open, relatively uniform, unimodal pore structure.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method of preparing a mesoporous carbon film, comprising:    (1) depositing a thin film of an aqueous carbohydrate/ silica sol-gel composition onto a substrate, the sol-gel composition being a homogeneous mixture containing 30-40 wt.% water, 35-50 wt.% polysiloxane gel precursor on a silica equivalent weight basis, and 4-30 wt.% water soluble carbohydrate on a carbon equivalent weight basis, the relative amounts of polysiloxane gel precursor and water soluble carbohydrate in the sol-gel composition being selected such that the carbon/silica nanocomposite film has a carbon to silica weight ratio of 1:1-1:11, as determined by thermogravimetric analysis;    (2) heating the thin film at 800-1000degreesC for a time sufficient to carbonize the carbohydrate in the thin film to form a carbon/silica nanocomposite film; and    (3) removing the silica from the carbon/silica nanocomposite film to provide a carbon film defining an open network of interconnected primary pores arrayed in a uniform, random manner throughout the carbon film, the pores having an average pore diameter of 2-3 nm, the diameters of the pores having a substantially unimodal pore diameter distribution, and not greater than 20 percent of the pores having a diameter of less than 1 nm.    DESCRIPTION OF DRAWING(S) - The figure shows the formation of the inventive unimodal mesoporous carbon film.