Molecular origins of Epoxy-Amine/Iron oxide interphase formation.

Hypothesis: Interphase properties in composites, adhesives and protective coatings can be predicted on the basis of interfacial interactions between polymeric precursor molecules and the inorganic surface during network formation. The strength of molecular interactions is expected to determine local segmental mobility (polymer glass transition temperature, Tg) and cure degree.

Experiments: Conventional analysis techniques and atomic force microscopy coupled with infrared (AFM-IR) are applied to nanocomposite specimens to precisely characterise the epoxy-amine/iron oxide interphase, whilst molecular dynamics simulations are applied to identify the molecular interactions underpinning its formation.

Reflectance in AFM-IR: Implications for Interpretation and Remote Analysis of the Buried Interface.

AFM-IR combines the chemical sensitivity of infrared spectroscopy with the lateral resolution of scanning probe microscopy, allowing nanoscale chemical analysis of almost any organic material under ambient conditions. As a result, this versatile technique is rapidly gaining popularity among materials scientists. Here, we report a previously overlooked source of data and artifacts in AFM-IR analysis; reflection from the buried interface.

Origin of micro-scale heterogeneity in polymerisation of photo-activated resin composites.

Photo-activated resin composites are widely used in industry and medicine. Despite extensive chemical characterisation, the micro-scale pattern of resin matrix reactive group conversion between filler particles is not fully understood. Using an advanced synchrotron-based wide-field IR imaging system and state-of-the-art Mie scattering corrections, we observe how the presence of monodispersed silica filler particles in a methacrylate based resin reduces local conversion and chemical bond strain in the polymer phase.

The Unexpected Role of Carbonate Impurities in Polyphosphate Corrosion Inhibition.

Polyphosphate corrosion inhibitors are increasingly marketed as chromate replacements for coil coated steel. The mechanisms underpinning corrosion prevention by these species is, however, not fully understood; corrosion inhibition is ordinarily assessed using electrochemical techniques, followed by ex-situ surface analysis. As a result, the formation of a clear film over cathodic sites is known to contribute to corrosion prevention, but little is known about its formation.

Investigating the Photocatalytic Degradation of Oil Paint using ATR-IR and AFM-IR.

As linseed oil has a longstanding and continuing history of use as a binder in artistic paints, developing an understanding of its degradation mechanism is critical to conservation efforts. At present, little can be done to detect the early stages of oil paint deterioration due to the complex chemical composition of degrading paints. In this work, we use advanced infrared analysis techniques to investigate the UV-induced deterioration of model linseed oil paints in detail.

Insights into Epoxy Network Nanostructural Heterogeneity Using AFM-IR.

The first direct observation of a chemically heterogeneous nanostructure within an epoxy resin is reported. Epoxy resins comprise the matrix component of many high performance composites, coatings and adhesives, yet the molecular network structure that underpins the performance of these industrially essential materials is not well understood. Internal nodular morphologies have repeatedly been reported for epoxy resins analyzed using SEM or AFM, yet the origin of these features remains a contentious subject, and epoxies are still commonly assumed to be chemically homogeneous.

Mapping water uptake in organic coatings using AFM-IR.

The long-term failure of seemingly intact corrosion resistant organic coatings is thought to occur via the development of ionic transport channels, which spontaneously evolve from hydrophilic regions on immersion, i.e., as a result of localized water uptake.

Tailoring the density of surface-tethered bottlebrushes.

Surface-tethered bottlebrushes have been prepared by ATRP grafting of the macroinitiator brush backbone onto plasmachemical-deposited poly(vinylbenzyl chloride) initiator nanofilms followed by ATRP growth of the side chains (bristles). The surface density of bottlebrushes can be precisely tailored by varying the plasmachemical deposition parameters employed for producing the poly(vinylbenzyl chloride) initiator nanolayers. Lateral force scanning probe microscopy has shown that poly(glycidyl methacrylate)-graft-poly(sodium styrene sulfonate) bottlebrush-decorated surfaces give rise to an enhancement in lubrication.

Surface actuation of smart nanoshutters.

Patterned polymer brush surfaces have been fabricated using the molecular scratchcard lithography technique, where a functional top nanolayer (acting also as a resist) is selectively removed using a scanning probe tip to expose underlying atom-transfer radical polymerization (ATRP) initiator sites. The lateral spreading of grafted polymer brush patterns across the adjacent functional resist surface can be reversibly actuated via solvent exposure. Effectively, this methodology provides a means for hiding/unveiling functional surfaces on the nanoscale.