Incorporation of nanofillers into the organic coatings might enhance their barrier performance, by decreasing the porosity and zigzagging the diffusion path for deleterious species. Thus, the coatings containing nanofillers are expected to have significant barrier properties for corrosion protection and reduce the trend for the coating to blister or delaminate. On the other hand, high hardness could be obtained for metallic coatings by producing the hard nanocrystalline phases within a metallic matrix. This article presents a review on recent development of nanocomposite coatings, providing an overview of nanocomposite coatings in various aspects dealing with the classification, preparative method, the nanocomposite coating properties, and characterization methods. It covers potential applications in areas such as the anticorrosion, antiwear, superhydrophobic area, self-cleaning, antifouling/antibacterial area, and electronics. Finally, conclusion and future trends will be also reported.

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Atomic force microscopy (AFM) has been extensively used for the nanoscale characterization of polymeric materials. The coupling of AFM with infrared spectroscope (AFM-IR) provides another advantage to the chemical analyses and thus helps to shed light upon the study of polymers. This paper reviews some recent progress in the application of AFM and AFM-IR in polymer science. We describe the principle of AFM-IR and the recent improvements to enhance its resolution. We also discuss the latest progress in the use of AFM-IR as a super-resolution correlated scanned-probe infrared spectroscopy for the chemical characterization of polymer materials dealing with polymer composites, polymer blends, multilayers, and biopolymers. To highlight the advantages of AFM-IR, we report several results in studying the crystallization of both miscible and immiscible blends as well as polymer aging. Finally, we demonstrate how this novel technique can be used to determine phase separation, spherulitic structure, and crystallization mechanisms at nanoscales, which has never been achieved before. The review also discusses future trends in the use of AFM-IR in polymer materials, especially in polymer thin film investigation.

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The mechanisms of the adsorption of stereoregular polymers are only poorly understood. This work is devoted to the study of the influence of PMMA tacticity and conformation on the interfacial behavior of the polymer. 1 H NMR usually used to determine the tacticity of PMMA in solution in CDCl3 can also be applied to systems containing the adsorbed polymer. The strong relative lowering of the peak ascribed to isotactic sequences has provided evidence of a stereospecific adsorption of the isotactic segments. These isotactic segments of i-PMMA show the most significant preference for the adsorption, while the isotactic sequences of the a-and s-PMMA also show this preference. The selective adsorption is more pronounced at room temperature than above the conformational transition temperature, namely, 50 °C. The conformation induced by the PMMA stereoregularity may, therefore, be considered as a significant factor in the adsorption process. The driving forces assumed to induce the stereoselective adsorption are discussed.

In order to prepare cured thin films thicknesses in the range of 90−300 nm, epoxy−amine mixtures of different concentrations in toluene are spin-cast onto oxidized silicon substrates. The glass transition temperature of the cured thin films is measured by microthermal analysis, revealing the existence of two distinct glass transitions temperatures for all the samples due to amine segregation at air/film interface. These transitions are ascribed to two layers. The upper layer properties of the film due to the air/polymer interface are independent of the film thickness. This layer is around 30 nm thick, and its glass transition temperature is about 97 °C and matches to a constant amine/epoxy composition at the air/film interphase. Consecutively, the film thickness reduction induces an increase of the epoxy excess in the sublayer, promoting side epoxy reactions revealed by aliphatic ether bonds formation. Thus, significant increase of the sublayer T g, in comparison to the T g of the bulk sample with an equivalent amine/epoxy ratio at the same amine conversion rate, is mainly due to these new ethers bonds for film thickness less than 160 nm. These bonds, surface catalyzed, are created at low temperature by the consumption of the epoxy excess. Etherification enhancement is finely controlled by the amine−epoxy off stoichiometry in the sublayer tuned by its thickness and mainly results in glass transition temperature increase at lightly amine conversion. At complete epoxy and high amine conversion reached by postcuring, etherification in the sublayer leads to a constant amount whatever the thickness of the sample. The glass transition temperature of the sublayer postcured is around 180 °C, equivalent to the bulk sample and does not bring out confinement effects.

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Thin 200-nm epoxy-amine mixtures were cured on silicon wafers with different surface chemistry to quantify the effect of the chemistry on the glass transition temperature evolution in ultra-thin thermosetting films. Two surface treatments were investigated: the first one only consisted in the activation of the silanols groups at the silicon surface, whereas the second one consisted in the grafting 3-aminopropyltrimethoxysilane (APTMS) monolayer on the silicon wafers. The epoxy films were deposited on these chemistry modified wafers by spin coating a toluene solution of DGEBA-amine mixture at stoichiometric ratio. The same cure processing was used for both samples. Thin films were analysed not only using microthermal and thermomechanical analysis to determine the relaxation transitions temperatures of these films but also using FTIR in infrared reflection absorption spectroscopy mode to determine the curing rate of these networks. It was found that all these thin films showed two different glass transitions, the first one at 96• C and was independent of the surface treatments, whereas the second one increasing from 142• C for the oxidised wafers surface to 167• C for the aminosilane grafted on the silicon wafer. The substrate chemistry extent on the film network structure, the interfacial bonds and interactions are discussed. This work also illustrates the interest in using microthermal analysis to obtain relevant temperature glass transition of thin film at sub-micrometre scale, strongly dependant of local structure and chemistry composition.