TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The substrate comprises steel strip, sheet, wire, rebar or blank; and comprises a coating selected from zinc, zinc oxide, zinc and aluminum, nickel, magnesium, silane or zirconium.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The water based solution is water.    TECHNOLOGY FOCUS - POLYMERS - Preferred Method: In the method (M1), the water based solution comprises organic solvent and water (preferably water), where the water content is greater than or equal to 50 (preferably greater than or equal to 80, especially greater than or equal to 90)% that is applied on the substrate. The water based solution comprising the polyetherimide intermediate is provided with metal oxide nanoparticle, corrosion inhibitor and/or halloysite. Preferred Components: The polyetherimide intermediate consists of at least one water soluble aliphatic polyetherdiamine; and comprises water soluble polyetherdiamine and water insoluble polyetherdiamine. The polyetherdiamine of the polyetherimide intermediate is polyether compound which contains at least one primary amino group attached to the terminus of polyether backbone, where the polyether backbone is based either on propylene oxide (PO) and/or ethylene oxide (EO). The aliphatic polyetherdiamine contains ether linkages (2-20, preferably 2-13, especially 2-6). The polyetherimide intermediate comprises epoxy based silane. The polyetherimide comprises an aromatic dianhydride or its derivative and aliphatic polyetherdiamine. EXAMPLE - 4,4'-Biphthalic anhydride (10 mmole) and de-ionized water (80 ml) were charged into a flask having nitrogen inlet. To this solution was added O,O'-bis(2-aminopropyl)polypropyleneglycol-block-polyethylene glycol-block polypropylene glycol (J1) (10 mmol) by forming white suspension. The white suspension was stirred under nitrogen at 60 degrees C for 4 hours until the aromatic dianhydride and J1 were solubilized. This solution was then stirred for further 8 hours to form water based solution (100% water) comprising polyetherimide intermediate (TAW1). The water based solution comprising TAW1 was then roll coated on to a degreased steel substrate and dried at 80 degrees C for period of 5 minutes to remove the water based solution. Following this drying step, the TAW1 coated steel substrate was cured at 200 degrees C for 5 minutes to form the corresponding polyetherimide. The polyetherimide has a dry film thickness of 2 mu m.