Layer-by-Layer (LbL) assembled films offer many interesting applications (e.g., in the field of nanoplasmonics), but are often mechanically feeble. The preparation of nanoprotective films of an oligomeric novolac epoxy resin with poly(ethyleneimine) using covalent LbL-assembly is described. The film growth is linear, and the thickness increment per layer pair is easily controlled by varying the polymer concentration and/or the adsorption times. The abrasion resistance of such cross-linked films was tested using a conventional rubbing machine and found to be greatly enhanced in comparison to that of classic LbL-films that are mostly assembled through electrostatic interactions. These robust LbL-films are then used to mechanically protect LbL-films that would completely be removed by a few rubbing cycles in the absence of a protective coating. A 45 nm thick LbL-film composed of gold nanoparticles and poly(allylamine hydrochloride) was chosen as an especially weak example for a functional multilayer system. The critical thickness for the protective LbL-coatings on top of the weak multilayer was determined to be about 6 layer pairs corresponding to about only 10 nm. At this thickness, the whole film withstands at least 25 abrasion cycles with a reduction of the total thickness of only about 2%.

The organic-inorganic hybrid multilayered composites are prepared using a unique combination of poly[(o-cresyl glycidyl ether)-co-formaldehyde] (CNER), amino modified montmorillonite (NH 2 -MMT), and polyethyleneimine (PEI). This tricomponent composite multilayer PEI(CNER/NH 2 -MMT/PEI) n deposited via layer-by-layer technique is based upon synergistic combination of covalent and hydrogen bonding. The growth of multilayer was monitored using UV-vis spectroscopy and ellipsometry. When subjected to optical analyses, the prepared multilayered composite films revealed profound optical transmittance 83%-87%. The surface morphological analysis by atomic force microscopy and scanning electron microscopy revealed uniform arrangement of organicinorganic components with relative increase in intensity of elements (C, N, O, Si) as confirmed by X-ray photoelectron spectroscopy studies. The multilayered composites possess 1.99 GPa hardness making them potential candidate for a number of applications where mechanical strength is desired. Moreover, significant resistance against alkaline and organic solvents at minimal deterioration of circa 0.12% has also been observed for the prepared films. The epoxy clay based thin films being robust, scratch resistant, hydrophilic, chemically inert, and mechanically strong are potential candidates for advanced environmental applications.

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