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In the present research, we evaluated the printability of inks that were formulated using an acrylate-endcapped urethane-based poly(ethylene glycol) hydrogel precursor (AUP) and a silicate-based nanoclay Laponite. Flow characterization of the AUP/ Laponite hydrogel inks revealed both yielding and shear thinning behavior, strongly dependent on the concentrations of the AUP and Laponite. In order to have a better insight into printability, the flow behavior along the cross section inside the printing needle was evaluated from the experimental shear flow data. The maximum stress values estimated inside the needle were applied to investigate the structural recovery of the inks using oscillatory rheology. Close analysis of the shear modulus recovery of the AUP/Laponite inks revealed a biexponential behavior, indicating a two-step recovery mechanism. The recovery mechanism is composed of fast and slow recovery steps and it appears that the shape fidelity after ink deposition is primarily controlled by the fast recovery contribution. Optimal printability was achieved for the ink formulation with the shortest characteristic time as well as a high modulus (>500 Pa) compared to the inks which could not be printed into well-defined structures. In the final part, cell interactivity of the three-dimensional (3D)-printed scaffolds was evaluated via live/dead cell assays.

Implementation of hydrogel precursors in two-photon polymerization (2PP) technology provides promising opportunities in the tissue engineering field thanks to their soft characteristics and similarity to extracellular matrix. Most of the hydrogels, however, are prone to post-fabrication deformations, leading to a mismatch between the computer-aided design and the printed structure. In the present work, we have developed novel synthetic hydrogel precursors to overcome the limitations associated with 2PP processing of conventional hydrogel precursors such as post-processing deformations and a narrow processing window. The precursors are based on a poly(ethylene glycol) backbone containing urethane linkers and are, on average, functionalized with six acrylate terminal groups (three on each terminal group). As a benchmark material, we exploited a precursor with an identical backbone and urethane linkers, albeit functionalized with two acrylate groups, that were reported as state-of-the-art. An in-depth characterization of the hexafunctional precursors revealed a reduced swelling ratio (36 MPa Young's modulus) compared to their difunctional analogs. The superior physical properties of the newly developed hydrogels lead to 2PP-based fabrication of stable microstructures with excellent shape fidelity at laser scanning speeds up to at least 90 mm s-1, in contrast with the distorted structures of conventional difunctional precursors. The hydrogel films and microscaffolds revealed a good cell interactivity after functionalization of their surface with a gelatin methacrylamide-based coating. The proposed synthesis strategy provides a one-pot and scalable synthesis of hydrogel building blocks that can overcome the current limitations associated with 2PP fabrication of hydrogel microstructures

Phenolic-based coating systems incorporating typical binding resins such as epoxies or polyesters were prepared along protocols mimicking relevant application conditions and are investigated using methods which are fairly standard in an industrial environment. Following a pragmatic approach, gravimetric analysis along with spectral analysis by FTIR spectroscopy of the insoluble gel fraction and liquid 1 H NMR spectroscopy for the soluble fraction were used in a quantitative way to investigate proven binder/crosslinker systems over a range of compositions. Furthermore, a close analysis of the soluble fraction data has been conducted following the statistical mean-field model of Miller-Macosko with proper adjustments to account for the investigated systems where the phenolic resin can crosslink with itself and with the binder, whereas the binder mainly links to the crosslinker in conjunction with chain extending end-end couplings. For the linear precursors considered here, end and side functions were treated as chemically distinct in the model.

The recent introduction of semicrystalline acrylated oligomers exhibiting fast photoinitiated free radical polymerization in the solid state calls for a deeper understanding of the mechanisms behin...

Efficient crosslinking of conventional photoreactive hydrogel precursors relies on the mobility of the reactive groups and is typically addressed from the liquid state. However, this represents a major limitation for many processing techniques of hydrogel materials. Herein, a model precursor is introduced that overcomes this challenge using a prepolymer designed to enable successful crosslinking in the solid state. The precursor is synthesized by connecting a flexible, mono-acrylated spacer to a semi-crystalline hydrophilic backbone polymer using a di-isocyanate linker. The resulting prepolymers exhibit excellent solid-state photoreactivity, even in the absence of a photo-initiator. As a proof of concept, the precursor has successfully been processed by: (1) solution electrospinning with subsequent solid-state photopolymerization (SSPP), (2) melt-based additive manufacturing with subsequent SSPP and (3) two-photon polymerization in the solid state. No cell adhesion takes place on bare crosslinked 3D-printed scaffolds whereas excellent cell adhesion is recovered after application of a gelatin methacrylamide coating. With this novel class of UV-reactive precursors unprecedented hydrogel processing avenues are opened.

Recently, a semi-empirical scaling model was introduced to account for the free-radical polymerization kinetics of acrylated urethane precursors in the solid-state. By describing the radical initiation process in more detail, the kinetic model is extended herein towards general free-radical crosslinking irrespective of the initial physical state of the multifunctional precursors. Effects referred to as radical trapping and caging in the literature are clearly specified and a closed-form expression with a limited number of adjustable parameters is obtained which can be compared to experimental kinetics. In particular, the relation between polymerization rate and functional conversion can be reduced to expressions with three and four parameters in the limits of “solid-state” and “steady-state” kinetics, respectively. In the case of photo-induced free-radical polymerization and within the slow decomposition regime of the initiator, the single parameter with an explicit dependence on the incident light intensity is predicted to behave proportionally. The model is validated by comparing the relevant expressions to original calorimetric data for the free-radical photopolymerization kinetics of different acrylate urethane precursors at two temperatures, providing illustrations for solid-to-solid and liquid-to-rubber transformations. Careful monitoring of the effect of light intensity corroborates the expected scaling and additionally offers reliable estimates for the kinetic coefficients of propagation and termination.

In the present work, a photopolymerized urethane-based poly(ethylene glycol) hydrogel is applied as a porous scaffold material using indirect solid freeform fabrication (SFF). This approach combines the benefits of SFF with a large freedom in material selection and applicable concentration ranges. A sacrificial 3D poly(ε-caprolactone) structure is generated using fused deposition modeling and used as template to produce hydrogel scaffolds. By changing the template plotting parameters, the scaffold channel sizes vary from 280 to 360 μm, and the strut diameters from 340 to 400 μm. This enables the production of scaffolds with tunable mechanical properties, characterized by an average hardness ranging from 9 to 43 N and from 1 to 6 N for dry and hydrated scaffolds, respectively. Experiments using mouse calvaria preosteoblasts indicate that a gelatin methacrylamide coating of the scaffolds results in an increased cell adhesion and proliferation with improved cell morphology.

Polymer colloids are usually prepared using thermally activated polymerization. Photo-induced techniques for the preparation of polymerized or crosslinked colloids have seldom been reported in the literature and to our knowledge none has found real application in industry. Here, we introduce a new approach to form insoluble crosslinked colloidal particles by in situ photopolymerization starting from aqueous dispersions of auto-dispersible acrylated oligomers originally developed for water-based UV-coating applications. Of particular interest is the relatively high rate at which particle polymerization takes place even in highly opaque conditions e.g. with particle loadings of more than 20 w/w% and particle sizes ranging from 40 up to 500 nm. In this paper, the preparation process is demonstrated with an immersion-type batch photoreactor and the properties of this new family of organic colloids are highlighted. Furthermore, we report the preparation of submicron sized containers by loading a hydrophobic compound (i.e. n -hexadecane) within a water-dispersible urethane acrylate shell followed by solidification of the container wall using radical photopolymerization with a suitable photoinitiator. The thermal and colloidal characteristics of these novel capsules are discussed in some detail and the potential application as nanoscaled phase-change material is highlighted.

Radiation-cured acrylate-based materials are used in a wealth of applications. For coatings in particular, adhesion is a key property and remains challenging for some substrates such as plastics and metals. Stress build-up during and after resin polymerization is a handicapping issue that may lead to defect formation or debonding which results in bad coating performances. Using the substrate deflection method, stress development has been investigated in ultraviolet(UV)-cured acrylate coatings based on an epoxy acrylate combined with mono-, di- and triacrylate diluents. The coatings were prepared in conditions relevant to industrial practice using high UV intensity and short processing times. Stress measurements were conducted according to the prescriptions of a recent ASTM standard. A new set of data is provided which shows that photo-cured epoxy acrylates develop low stress as compared to other dilution acrylates (monomers). When formulated with most of the reactive diluents, the stress does not exceed 4 MPa as long as the dilution factor stays below 50%. This is fairly low given the high conversion rates. For vitrified coatings, it appears that in addition to polymerization stress, thermally-induced stress represents a non-negligible contribution to the overall stress. In an industrial UV-curing process however, the latter contribution is estimated to be less than 2–3 MPa. Lastly, an estimate of the interfacial fracture toughness between trimethylolpropane triacrylate and carbon steel is inferred from the stress data.

The waterborne nature of radiation curable polyurethane dispersions largely respond to the current environmental concerns and do not require any additional coalescent since the film formation (drying) and hardening (photo-curing) take place in distinct steps. It is possible to design aqueous dispersions with distinct polymer particle populations resulting in micro-structured coatings with optimized properties over a wide range of curing conditions. Mixed dispersions based on hard and soft acrylated polyurethane particles were used as model systems for the present study. The minimum film formation temperature has been investigated as a function of the hard:soft polymer ratio. The elastic modulus of the dry coatings shows a reinforcing effect consistent with the inclusion of hard domains in a soft continuous matrix. However, the level of reinforcement is not properly predicted by the usual mechanical models and it is qualitatively accounted for by assuming a composition gradient (interphase) between the hard domains and the matrix. The multiple-phase structure was clearly established by Atomic Force Microscopy in agreement with thermal analysis data. Furthermore the local nanoscale mechanical properties were mapped using a new imaging mode based on real-time force–distance curve analysis. Finally, the coatings prepared using this multiple-phase pattern present a clear benefit over conventional homogeneous coatings by offering an improved balance of chemical and mechanical resistance in pigmented systems applied on melamine-coated MDF panels.

In this report, we describe the application of standard thermodilatometry (TD) as a tool to evaluate the thermal behavior of laminated glass assemblies where two glass layers are bonded together by a polymer interlayer. The measurement of the displacement perpendicular to the plane of the glass multilayer enables to follow the thermal expansion up to the point where interfacial debonding, thermal degradation, or another thermal event takes place. The effect of heating rate has been investigated and a procedure is eventually proposed to estimate the onset temperature at interfacial failure from the TD data. It is also shown that TD measurements of the interlayer along the side of the glass laminate give a sharp signal at interfacial failure. Finally, following the sandwich seal model where it is assumed that, during heating, the constrained interlayer is in compression due to the mismatch in thermal expansivity between the outer glass and the inner polymer layer, we establish the stress–strain behavior of the interlayer up to the debonding temperature. Viscoelastic and structural relaxation of the interlayer are taken into account empirically from modulus and thermal expansion data collected along similar thermal paths.

The complex modulus E(jw) characterizes the visco-elastic behavior of a material. Using a system identification approach, this modulus can be measured via broadband modal analysis experiments. The technique is applied to determine the equivalent complex modulus E(jw), with its uncertainty bound, of multilayer glass beams from transversal vibration experiments in free-free boundary conditions. This property is related to the effective complex bending stiffness of the laminated glass specimen, and is further used for predicting the sound transmission loss of a multilayer plate. The data are rationalized in the terms of the linear visco-elastic properties of the polymer interlayer.

Model aqueous dispersions of polystyrene, poly(methyl methacrylate), poly(n-butyl acrylate) and a statistical copolymer poly(n-butyl acrylate-co-methyl methacrylate) were studied using xenon NMR spectroscopy. The (129)Xe NMR spectra of these various latexes reveal qualitative and quantitative differences in the number of peaks and in their line widths and chemical shifts. Above the glass transition temperature, exchange between xenon sorbed in the particle core and free xenon outside the particles is fast on the (129)Xe spectral time-scale and a single (129)Xe signal is observed. At temperatures below the glass transition temperature, the exchange between sorbed and free xenon is slow on the (129)Xe spectral time-scale and two (129)Xe NMR signals can be observed. If the signal of sorbed (129)Xe is observed, its chemical shift, line width and integral relative to the integral of free (129)Xe can be used for the characterization of the particle core. The line width of free (129)Xe provides the residence time of xenon outside the particles and can be used to determine the rate constant characterizing the kinetics of penetration of xenon in the particles. This rate constant emerges as promising parameter for the characterization of the polymer particle surface., info:eu-repo/semantics/published

The introduction of new tailor-made (meth)acrylated oligomers has extended the potential use of the radiation curing technology to metal coating applications where adhesion, flexibility and corrosion resistance are of prime importance. In this paper, we discuss the properties of three fairly simple clearcoat systems spanning a range of glass transition temperatures between ≈10 and 70 °C. The systems were obtained by combination of two original urethane acrylate resins and two reactive diluents. Practical performance tests typically used to establish coating profiles in the metal industry (i.e., mechanical testing, adhesion, salt-spray test, etc.) were performed on ultraviolet (UV)-coated galvanised steel. In addition, the barrier properties of coated steel panels were systematically investigated at different coating thicknesses using electrochemical impedance spectroscopy. These results are analysed in terms of relevant physico-chemical characteristics such as conversion, volume contraction, swelling, viscoelastic and tensile behaviour determined on free-standing coating layers of the three formulations.

With the goal of developing new pressure sensitive adhesive systems, the miscibility and the phase morphology of blends between novel symmetric four-arm star “all-acrylate” block copolymers synthesized by atom transfer radical polymerization (ATRP) and a rosin ester resin tackifier was studied with a combined differential scanning calorimetry (DSC) and atomic force microscopy (AFM) approach. Copolymer–resin compositions with increasing resin content in the blend were studied. The DSC results show good miscibility for compositions lower than 60 wt%, with a single glass transition at a temperature between those of the two pure compounds. The AFM results indicate that the initial two-phase morphology typical of the block copolymer matrix is preserved up to 60 wt% of resin. Above that value, a third phase, attributed to aggregates of the pure resin, is observed. Upon ageing, the homogeneous systems (e.g., blends with 40 wt% of resin) undergo a slow migration of the tackifying resin towards the surface of the sample, which can be understood in terms of surface free energy considerations. This eventually leads to the formation of a layer of pure resin at the surface.

The chemistry of radiation curable polyurethane dispersions is outlined with an emphasis on the microstructure of the aqueous polymer dispersion and the possible interactions with associative thickeners. The steady-shear flow was studied for two model dispersions prepared from the same unsaturated polyurethane but showing significantly different particle size distributions. A hydrophobically modified ethoxylated urethane (HEUR) associative thickener with a linear structure was incorporated at different amounts to the dispersions with varying particle volume fractions. The steady-state viscosity at 25 and 10 °C was always reached quickly after instant flow rate changes so that no significant thixotropic effects were reported within the experimental timescale. Without thickener, the flow curves of the two model dispersions exhibited a Newtonian behavior except at the highest volume fractions where shear thinning became apparent. The maximum packing values determined from the Krieger–Dougherty relationship were essentially the same for the two systems. In the presence of thickener, the flow curves were characterized by a Newtonian plateau followed by a marked shear thinning region even at low particle volume fractions. This behavior typically suggests the formation of a physical network between polyurethane particles and thickener molecules partly adsorbed onto the polymer surface. The zero-shear viscosity of the two dispersions was compared with respect to: (i) particle volume fraction and (ii) particle surface area at different HEUR concentrations. At a given volume fraction, the particle size affects the viscosity of thickened models. As a corollary, a relationship is found between the particles size and the level of thickener required to reach a target viscosity. This study offers practically relevant data in terms of application conditions and provides a better insight into the thickening protocol.

Novel “all-acrylate” block copolymers have been synthesized by ATRP with a simple and cost-effective one-pot-two-step process. The (A−B)n copolymers are composed of an elastomer segment (A = P(2EHA-co-MA) = poly(2-ethylhexyl acrylate-co-methyl acrylate)) and a thermoplastic segment (B = PMMA = poly(methyl methacrylate)). To study the relationship between the molecular architecture and the mechanical properties, a four-arm radial block copolymer (A−B)4 is compared to the linear diblock (A−B)1 and symmetric triblock (A−B)2 and compounds of similar composition. Atomic force microscopy (AFM) shows that all block copolymers present a well-defined microphase separation, which is confirmed by the observation of two glass transitions in DSC. Thermomechanical data from viscoelastic, indentation, and tensile measurements are discussed in terms of the structural characteristics of the copolymers. The increase in the complexity of the molecular structure results in an enhanced elastic response, and the stress−strain ...

A novel four-arm radial block co-polymer (A-B)4 obtained by atom transfer radical polymerization (ATRP) and a random (statistical) co-polymer of similar composition have been prepared. In the presence of rosin esters, these materials show pressure-sensitive adhesive (PSA) properties. The aim of this investigation was to study the relationship between the molecular architecture of tackified systems and their typical PSA properties. First, the miscibility of these two co-polymers with a rosin ester resin was investigated. Then, the performance of PSA such as peel strength and shear resistance was studied. In contrast to the random co-polymer, the block co-polymer presents two glass transitions, as evidenced by DSC and TMA. Atomic force microscopy (AFM) further confirmed the well-defined microphase separation. The Gordon–Taylor expression provides an empirical description of the dependence of the T g on the tackifier content for the random co-polymer and the elastomer phase of the block co-polymer. The DSC r...

Radiation-curable polyurethane dispersions (UV-PUDs) are colloidal dispersions whose stability is mainly ensured by the electrostatic repulsion between the negatively charged polymer particles. In this article, particle stabilization is presented in terms of the physico-chemical characteristics of the polymer dispersion and its microstructure. The phenomenon of the colloidal destabilization at higher temperature is studied by multiple light scattering, then correlated with the evolution of the particle size distributions and the measurement of the apparent critical coagulation concentration of a salt as an indication of the energy barrier at the surface of the particles. The investigation of selected chemical parameters of the polymer on the colloidal stability aims to identify the most relevant ones with an understanding of the underlying mechanism. The study underlines that UV-PUDs constitute a waterborne polymer family with its own identity, adding complexity to the traditional radiation curing chemistry. Finally, it highlights the new perspectives offered for novel environmental-friendly products with high-end performance and extended stability and robustness.

The volumetric determination of the surfactant adsorption density at maximum packing (saturation) is studied in binary latex blends. A phenomenological description for latex mixtures that are not free of surfactant prior to titration predicts a quadratic dependence for the saturation adsorption density as a function of the fractional surface area of the latex compounds. The expected behavior was verified experimentally from conductometric titrations of sodium dodecyl sulfate in blends of homopolymer latices cleaned with the serum replacement technique. Accordingly, it is shown that surfactant titration of binary latex blends provides indications about the level of cleaning of the mixed compounds. Furthermore, when latex mixtures are prepared by using a surfactant-free reference latex, this approach may be used for the estimation of the saturation adsorption area of the bare polymer surface for an incompletely cleaned latex. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3226–3230, 2004

The magnetic relaxation dispersion from the water deuteron resonance in aqueous colloidal silica sols has been measured with the field-cycling technique in the frequency range from 1.5 kHz to 7.7 MHz. Dispersion profiles were recorded as a function of pL, L stands for a general hydrogen atom, in the range 2-11 for two sols with different particle size and at two temperatures. The profiles were well described by a Lorentzian dispersion function with an amplitude of ‚ and an apparent correlation time of U. The near invariance of U with particle size, temperature, and pL demonstrates that the usual motional narrowing theory of spin relaxation is not applicable. A more general, nonperturbative theory, however, can quantitatively rationalize the data and yields, through a global fit, physically meaningful values of the microscopic parameters in the model. The analysis shows that the dispersion is partly due to long-lived water molecules and partly to silanol deuterons in rapid exchange with water. The silanol contribution is about 50% at pL 5, increasing to 90% at pL 8-10. Over most of the pL range, U is essentially a measure of the residual quadrupole frequency of water and silanol deuterons and, hence, is not directly related to a motion in the system. The long-lived water molecules contributing to the dispersion have a residence time distribution spanning the microsecond range and are presumably trapped in micropores at the silica surface. The surface density of such trapped water molecules

The proton spin-lattice relaxation rates of amorphous colloidal suspensions are reported over a wide Larmor frequency range for varying degrees of isotopic dilution. At low magnetic fields, the amplitude of the relaxation dispersion reveals a non-linear dependence upon deuteration. This behaviour is primarily attributed to isotopic fractionation effects of slow exchanging hydrogens situated at solvent-shielded sites on the silica surface, but which are involved in dipolar interactions with readily solvent accessible proton species. A theoretical spin relaxation model is proposed which accounts for the isotope dilution effects in a multiple-phase system composed of the abundant slow-relaxing bulk spins and spin environments in mutual dipolar interaction at the oxide interface. The broadness of the observed relaxation dispersions is treated as a superposition of a discrete number of Lorentzian-like power spectra. At least two relaxation components are resolved from the present dispersion data which obviously reflect the heterogeneity of the proton sites at the silica surface. Each component seems to consist of a water and a pH dependent silanol contribution. The exchange of the observed proton classes has been estimated to occur on the microsecond time scale. An overall quantitative analysis of our relaxation dispersion data at different H/D ratios reveals considerable isotope fractionation between some slow exchanging surface hydrogens and the water solvent. Fractionation factor values

The magnetic-field dependence of the water-proton spin–lattice relaxation time (referred to as nuclear-magnetic-relaxation dispersion) has been measured in colloidal silica suspensions after addition of calibrated MnCl2solutions. The NMRD curves always show the diamagnetic dispersion normally observed in a paramagnetic ion-free silica sol but, above pH 7, also reveal a supplementary relaxation peak at high magnetic fields typical for paramagnetic ion complexes adsorbed onto the silica. The paramagnetic contribution increases linearly with ion concentration until a contribution attributed to free Mn2+aquo-ions is observed as well. The ion adsorption density[formula]is temperature and pH sensitive; e.g., no adsorption is observed at pH 2.4. The paramagnetic contribution to the experimental NMRD curves, due to adsorption of Mn2+aquo complexes onto the silica, is satisfactorily described by the Solomon–Bloembergen–Morgan equations. The estimated parameters, resulting from least-squares comparisons, are consistent with the assumption that the primary hydration shell of the adsorbed ion is retained.

The magnetic-field dependence of the water-proton spin-lattice relaxation rate 1/ T 1 is reported for aqueous colloidal silica suspensions as a function of temperature, particle size, silica concentration, and isotopical proton dilution. At low concentrations, it is found that T 1 is essentially determined by a coupling of solvent protons with nonexchangeable protons situated near the colloid surface. Comparison of NMRD and photon correlation spectroscopy measurements indicates that interparticle interactions increase the NMR relaxation rates at low frequencies. Finally, it is also shown that, in contrast to protein solutions, there is no evident link between the NMRD inflection frequency and the correlation time of the rotational Brownian motion of the colloidal particles.

This work revisits the use of surfactant titrations for the characterization of latex particle surfaces. Experiments were performed to study the effect of comonomer composition and the effect of acid comonomers, and the technique is applied to the characterization of particle morphology in composite latices for several different systems. It is confirmed that the packing density of surfactant on a polymer surface is a linear function of copolymer composition. Inclusion of acid comonomers has the expected effect of decreasing the amount of surfactant adsorbed on the polymer surfaces. The usefulness of the technique in the determination of particle morphology is demonstrated, in particular toward the detection of thin layers of either seed or second-stage polymer on the particle surface which are not easily detected by other techniques such as transmission electron microscopy (TEM). Finally, it is shown that the use of acid comonomers in composite particles greatly reduces the usefulness of the surfactant titration technique for morphology characterization. A possible explanation for this effect is proposed.

The reoccurrence of water molecules in crystal structures of RNase T1 was investigated. Five waters were found to be invariant in RNase T1 as well as in six other related fungal RNases. The structural, dynamical, and functional characteristics of one of these conserved hydration sites (WAT1) were analyzed by protein engineering, X-ray crystallography, and (17)O and 2H nuclear magnetic relaxation dispersion (NMRD). The position of WAT1 and its surrounding hydrogen bond network are unaffected by deletions of two neighboring side chains. In the mutant Thr93Gln, the Gln93N epsilon2 nitrogen replaces WAT1 and participates in a similar hydrogen bond network involving Cys6, Asn9, Asp76, and Thr91. The ability of WAT1 to form four hydrogen bonds may explain why evolution has preserved a water molecule, rather than a side-chain atom, at the center of this intricate hydrogen bond network. Comparison of the (17)O NMRD profiles from wild-type and Thr93Gln RNase T1 yield a mean residence time of 7 ns at 27 degrees C and an orientational order parameter of 0.45. The effects of mutations around WAT1 on the kinetic parameters of RNase T1 are small but significant and probably relate to the dynamics of the active site.

Zinc and iron substrates were coated with polyester acrylate films. The samples were cured by an exposure to different doses of ultraviolet (UV) radiation energy at different radiant fluxes of the UV light source. Infrared spectroscopy was used to estimate the resulting degree of macromolecular cross-linking. Its effect on the barrier properties of the coating was investigated by Electro-chemical Impedance Spectroscopy (EIS). A reduced water uptake and a reduced swelling of the coating as well as a decelerated diffusion of water through the polymer bulk were detected on polyester acrylate coated zinc samples that were exposed to increasing UV energy doses at low UV light intensity. With the Scanning Kelvin Probe (SKP), a similar tendency was detected for the resistance of polyester acrylate/iron oxide/iron interfaces against cathodic delamination. In contrast, curing with large energy doses at high UV intensity led to decelerated ion transport kinetics along the interface, but did not further improve the barrier properties of the coating. This indicated that SKP data gained on Fe substrates and EIS data recorded on Zn substrates can be correlated if UV curing does not result in strong tension within the polyester acrylate films.