A facile method for generating Michael acceptor thin films via amine substituted poly(vinyl methyl ketone)

Alpha-morpholine substituted poly(vinyl methyl ketone) (PVMK) was determined to undergo rapid self-crosslinking by short-term vacuuming (i.e., 30-60 min) or curing at 70-100 degrees C. The chemical transformations involved were monitored by TGA, DSC, FT-IR, (HNMR)-H-1 and solid-state C-13 NMR techniques. These experiments revealed an "unzipping-like" mechanism yielding multi conjugated enone structure via consecutive deamination by beta-hydrogen elimination and simultaneous Diels-Alder cyclization resulting in crosslinking. This chemistry was exploited for generating Michael acceptor thin film coatings on silica nanoparticles, in which the silica was impregnated with morpholine substituted poly(vinyl methyl ketone) and simply heated at 100 degrees C. The dense polyene functional films so formed were demonstrated to add amines and thiols at room temperature. The resulting silica nanoparticles were employed to form homogenous composite films using poly(butyl acrylate-stat-methylmethacrylate) as carrier matrix. Morpholine substituted poly(vinyl methyl ketone) (MSP) seems to be generally applicable for surface modification of different inorganic surfaces with organics.