NOVELTY - The method for assembling nano objects onto a freestanding macroscopic structure for electron field emission cathodes, comprises processing nano objects to a desired aspect ratio and chemical functionality, admixing the processed nano objects with a solvent (750) such as water and/or alcohol to form a suspension, submersing a substrate into the suspension, changing the concentration of the suspension to control deposition of the nano objects onto the substrate thus assembling the macroscopic structure onto the substrate, and patterning a surface of the substrate.    USE - The method is useful for assembling nano objects onto a freestanding macroscopic structure (claimed), which is useful for devices including electron field emission cathodes in field emission displays, cold-cathode x-ray tubes, microwave amplifiers, ignition devices, electrodes batteries, fuel cells, capacitors, supercapacitors, optical filters and polarizers, sensors and electronic inter-connects.    ADVANTAGE - The method is capable of self assembling of the nano objects into patterned structures with a controlled thickness, density and a controlled orientation of the nano objects, and allows for higher packing densities at room temperature.    DETAILED DESCRIPTION - The method for assembling nano objects onto a freestanding macroscopic structure for electron field emission cathodes, comprises processing nano objects to a desired aspect ratio and chemical functionality, admixing the processed nano objects with a solvent (750) such as water and/or alcohol to form a suspension, submersing a substrate into the suspension, changing the concentration of the suspension to control deposition of the nano objects onto the substrate thus assembling the macroscopic structure onto the substrate, patterning a surface of the substrate such that the substrate surface (760) comprises a first region and a second region, removing the substrate from the suspension, and depositing a second material onto the nano objects assembled on the substrate to form a multi layer structure. The suspension has a concentration, a temperature and a pH level. The nano objects comprise a mixture of single wall carbon nanotubes (SWNTs) and multi wall carbon nanotubes (MWNTs). The operation of processing the nano objects comprises synthesizing the carbon nanotubes, purifying the carbon nanotubes by reflux in a hydrogen peroxide solution, modifying both a length of the carbon nano tubes and a chemical property of the carbon nano tubes, synthesizing the SWNTs by a laser ablation, arc discharge, chemical vapor deposition and pyrolysis, purifying the SWNTs by oxidation and/or filtration, chemically modifying the SWNTs, and reducing an aspect ratio of the SWNTs by reacting the SWNTs with nitric acid and/or sulfuric acid and with ultrasonication. A length of the processed SWNTs is 0.1-10 microns. The concentration of the suspension of carbon nanotubes in water is 0.01 grams of carbon nanotube per liter of water and 10.0 grams of carbon nanotube per liter of water. The substrate comprises a hydrophilic region and a hydrophobic region such that the SWNTs deposit on the hydrophilic region of the substrate and a hydrophilic glass patterned with a hydrophobic material. The first region has an affinity to the nano objects and the second region has no affinity to the nano objects, where changing the concentration of the suspension deposits the nano objects on the first region of the substrate surface. The substrate has a planar or a curved configuration. The operation of changing the concentration of the suspension comprises changing the concentration of the suspension by gradual evaporation of the solvent such that the nano objects deposit on the substrate along an air/liquid/substrate triple line of the substrate. The submersing operation comprises submerging the substrate into the suspension in a vertical orientation relative to the suspension. Longitudinal axes of the nano objects are aligned in a direction of the air/liquid/substrate triple line. The substrate comprises a hydrophobic coating. The hydrophilic and hydrophobic coatings form a pattern on the substrate. The processed pre-formed nano objects form onto the substrate at the hydrophilic coating thus forming a pattern corresponding to the pattern formed by the hydrophilic and hydrophobic coatings. The nano objects assemble into the macroscopic structure around the seed crystal such that a structure of the macroscopic structure is the same as a structure of the seed crystal. The macroscopic structure has a thickness of 1 nanometer to 10 microns and an area of 1 micronx 1 micron and 10 cmx 10 cm. The nano objects comprise nanowires/nanorods. The coating operation comprises spin coating, spraying, and electrophoresis. The second material is a metal, a semiconductor, a polymer, an inorganic material, an organic material and/or a biological material. The hydrophobic material is a photoresist and/or a mono-layer of hydrophobic functional groups. INDEPENDENT CLAIMS are included for:    (1) a free-standing multilayer structure;    (2) a method for fabricating electron field emission cathodes; and    (3) a field emission cathode.    DESCRIPTION OF DRAWING(S) - The diagram shows a method of assembling elongated nano objects onto a freestanding macroscopic structure.    Body (710)    Tail (720)    Container (740)    Solvent (750)    Substrate surface. (760)