TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The solvent is selected from toluene, trichloroethylene, carbon tetrachloride, chlorobenzene, chloroform, cyclohexane, benzene, ortho-dichlorobenzene, butyl acetate, methyl isobutyl ketone, methylene dichloride, ethylene dichloride, 1,1-dichloroethane, isopentylacetate, hexane, ethyl acetate, diethyl ether, 1,4-doxane, tetrahydrofuran, acetophenone, isophorone, nitrobenzene, 2-nitropropane, acetone, diacetone alcohol, methyl-2-pyrrolidone ethylene glycol monobutyl ether, cyclohexanol, nitroethane, ethylene glycol monoethyl ether, dimethylformamide, 1-butanol, gamma -butyrolactone, ethylene glycol monomethyl ether, dimethyl sulfoxide, propylene carbonate, nitromethane, dipropylene glycol, ethanol, diethylene glycol, propylene glycol, methanol, ethanolamine, ethylene glycol, formamide, methylcyclohexane, decalin and/or water.    TECHNOLOGY FOCUS - POLYMERS - Preferred Method: In method (M1), exposing takes place for at least 220 seconds (preferably 220 seconds to ten minutes, especially 220-280 seconds); and at least one of the bonding surfaces formed with microstructured features has a magnitude of surface roughness in the region of 50-250 nm prior to the exposing which reduces to less than 25 nm as a result of the exposing. In method (M2), the surface has a magnitude of surface roughness in the region of 50-250 nm prior to the exposing which reduces to less than 25 nm as a result of the exposing. Preferred Components: At least one of the first and second substrates is made of a thermoplastic polymer selected from polyethylenes; polypropylenes; poly(1-butene); poly(methyl pentene); poly(vinyl chloride); poly(acrylonitrile); Teflon (RTM: poly(tetrafluoroethylene) (PTFE)), poly(vinyl acetate); polystyrene; poly(methyl methacrylate) (PMMA); ethylene-vinyl acetate copolymer; ethylene methyl acrylate copolymer; styrene-acrylonitrile copolymers; cycloolefin polymers and copolymers and/or their derivatives (preferably PMMA or cycloolefin polymers and copolymers). The vapor of the solvent is capable of solubilizing, at least one of the first and second substrate, which is made of a material. The solvent vapor can be selected to be capable of solubilizing both the first and the second substrates. At least one of the first and second substrates is made of PMMA and the solvent is chloroform. At least one of the first and second substrates is made of cycloolefin polymers and copolymers and the solvent is cyclohexane. The first substrate is made of a thermoplastic polymer and the second substrate is made of the thermoplastic polymer or a further thermoplastic polymer. EXAMPLE - No suitable example given.