NOVELTY - An optically transparent super-hydrophobic material comprises an optically transparent polymeric layer having a first surface and an opposing second surface, where a portion of the first surface has been plasma-treated with oxygen and a fluorine containing compound, where the treated surface includes nano-or micro-structures that are etched into the first surface and that are chemically modified with the fluorine containing compound.    USE - The optically transparent super-hydrophobic material is used for protecting a substrate or article of manufacture from soiling; and maintaining or increasing the efficiency of a photovoltaic cell or protecting the outermost surface of a photovoltaic cell from soiling (all claimed).    ADVANTAGE - Due to their optical transparency, chemical and thermal robustness, weatherability, and self-cleaning performance, the super-hydrophobic materials are useful in high performing solar cell units in harsh semi-arid environments.    DETAILED DESCRIPTION - An optically transparent super-hydrophobic material comprises an optically transparent polymeric layer having a first surface and an opposing second surface, where a portion of the first surface has been plasma-treated with oxygen and a fluorine containing compound, where the treated surface includes (i) nano-or micro-structures that are etched into the first surface and that are chemically modified with the fluorine containing compound, where the nano-or micro-structures have a height to width aspect ratio of greater than 1; and (ii) a water contact angle of greater than or equal to 150 degrees ; where the optically transparent polymeric layer retains its optical transparency after the plasma-treatment. INDEPENDENT CLAIMS are:    (1) a method of preparing the optically transparent super-hydrophobic material defined above by (a) obtaining an optically transparent polymeric layer having a first surface and an opposing second surface, where the first surface has a water contact angle of less than 150 degrees ; (b) subjecting a portion of the first surface of the polymeric layer to a first plasma comprising oxygen under reaction conditions sufficient to obtain nano-or micro-structures that are etched into the polymeric layer, where the nano-or micro-structures have a height to width aspect ratio of greater than 1; and (c) subjecting the treated surface from (b) to a second plasma comprising a fluorine containing compound under reaction conditions sufficient to chemically modify the nano-or micro-structures with the fluorine containing compound, where the treated surface from step (c) has a water contact angle of greater than or equal to 150 degrees , and where the optically transparent polymeric layer from (a) retains its optical transparency after steps (b) and (c);    (2) a method of protecting a substrate or article of manufacture from soiling by disposing the optically transparent super-hydrophobic material defined above onto a substrate or article of manufacture, where the super-hydrophobic material protects the substrate or article of manufacture from soiling; and    (3) a method of maintaining or increasing the efficiency of a photovoltaic cell or protecting the outermost surface of a photovoltaic cell from soiling by disposing the optically transparent super-hydrophobic material defined above onto the outermost surface of the photovoltaic cell, where the efficiency of the photovoltaic cell is maintained or increased by protecting the outermost surface of the photovoltaic cell from soiling.