The distribution of two-phase polymer blends depends on the interactions and chemical structure of the polymer components, their compatibility with the substrate, and the processing conditions. In this study, we report a multimodal correlative workflow combining AFM, ToF-SIMS, Electron Microscopy, and high-resolution Helium Ion Microscopy-SIMS (HIM-SIMS), with the latter enabling chemically resolved imaging of phase-separated PS/ PMMA thin films at sub-15nm lateral resolutions. Spin-coated blends annealed exhibit surface reorganization into micron-scale droplets on a continuous matrix, as revealed by AFM. ToF-SIMS confirms the presence of both polymers at the outermost surface but cannot resolve sub-100 nm domains. HIM-SIMS overcomes this limitation by providing simultaneous secondary-electron imaging and nanoscale chemical maps. By employing deuterated PS as an isotopic label, PS-rich domains can be unambiguously distinguished from PMMA, overcoming the inherent ambiguity arising from overlapping molecular fragments in non-deuterated polymer systems. This correlative methodology offers a powerful platform for probing surface segregation, chemical heterogeneity, and interfacial organization in ultrathin polymer films, with relevance for coatings, electronics, and soft-matter interfaces.

This study reports the effect of pH (2, 7, 10) and heat treatment (80 °C for 30 min) on the oil–water (o/w) interfacial behavior of hemp seed protein isolate (HPI) aqueous dispersions. The physicochemical, interfacial adsorption, rheology, and emulsifying properties of protein dispersions were evaluated. HPI dispersions at pH 10 exhibited the highest water solubility (60%), the greatest net charge (−27 mV), and the lowest hydrophobicity (~5 a.u.), promoting o/w interfacial pressure (π) and interfacial viscoelasticity. Strong interfacial viscoelastic protein layers (E* = 25 mN/m) were also observed under acidic conditions (pH 2), where proteins exhibited high solubility (40%), a high positive net charge (21 mV), and increased hydrophobicity (46 a.u.). HPI dispersions in their neutral state (pH 7) were not able to form stable o/w emulsions due to their poor physicochemical properties such as low solubility (18%), low surface charge (−18 mV), and hydrophobicity (~5 a.u.). Heat treatment significantly increased the charge and hydrophobicity of both neutral and alkaline proteins (~30 mV and ~10 a.u., respectively), increasing their particle size distribution and ultimately reducing their interfacial protein layer elasticity (E* = 20 and 13 nM/m, respectively). While particles at acidic conditions showed high thermal resistance, heat treatment improved the emulsifying stability in alkaline conditions while further reducing it in the neutral state. Overall, HPI dispersions demonstrated the ability to form stable emulsions at both alkaline and acid pHs, with those formed at pH 2 exhibiting a lower droplet size and superior stability.

Heretofore, natural eutectic mixture-based solvents (NADES) have gained popularity in the field of cellulose chemistry. The present work explored the efficacy of combined NADES - ultra-high-pressure homogenization (UHPH) processing to transform microcrystalline cellulose (MCC) into nanofibrillar cellulose (CNF). Eutectic mixtures of choline chloride (ChCl) with glycerol, urea, malic, oxalic, or formic acid were employed for the pretreatment of MCC at 90 degrees C for 1 h. Then, NADES-treated MCC was UHPH processed at 2500 bar for 20 cycles. Cellulose's morphological and size changes during NADES and UHPH processing were monitored using dynamic light scattering and optical microscopy. The 20-fold UHPH processed CNFs were investigated for their chemical structure, crystallinity, thermal properties as well as the rheological behavior of their aqueous suspensions. DLS and microscopic assessments demonstrated a decrease in cellulose particle size proportional to the UHPH passes number. The ChCl-glycerol and -urea treated cellulose exhibited thinner fibers compared to the others. In contrast, the ChCl-malic and oxalic acid treated celluloses were morphologically closer to CNC, likely due to acid hydrolysis. Following DES pretreatment, the cellulose crystallinity increased, but after UHPH, it decreased, as high pressure effectively disrupted the crystalline regions. In addition, we found that the ChCl-glycerol, -urea, and -formic acid treated cellulose suspensions were more viscous, likely due to lower surface charge and fiber entanglement, while others showed lower but still elevated viscosity compared to pure CNCs at the same concentration. In conclusion, the combination of DES and UHPH is an efficient strategy to produce nanocellulose with good thickening properties.

This study elucidated the role of microalgal proteins, specifically spirulina (SPI), chlorella (CPI), and their equal parts blend, in structuring sodium alginate-based (NaAlg) cryogels and modulating the survivability and adhesion properties of Lacticaseibacillus rhamnosus GG (LGG). All matrices ensured near-complete preservation of LGG during freeze-drying (∼10 log CFU g-1), reflecting synergistic stabilisation via cryo-concentration, hydrogen bonding, and vitrification within the protein-polysaccharide network. Storage stability was primarily governed by water activity and temperature but was strongly coupled with thermophysical properties: higher glass transition temperatures (Tg) and glassy-state conditions significantly reduced inactivation kinetics, with SPI-based cryogels exhibiting the longest shelf-life (up to 320 days at aw 0.11, 20 °C). During semi-dynamic digestion, protein-dependent colloidal transitions dictated LGG protection and release. SPI systems formed compact gastric aggregates that limited enzyme diffusion and enabled controlled intestinal release, resulting in superior post-digestion viability (∼9.6 log CFU g-1), whereas CPI and SPI:CPI matrices showed greater losses. These functional differences were mechanistically linked to microstructural features of the cryogels, including highly porous (76-78%) architecture, the protein-specific pore-wall morphology, and aggregation behaviour, despite similar bulk mechanical properties e.g., stiffness and hardness. SPI cryogels preserved LGG cell adhesion to the mucus layer of co-culture model of the intestinal epithelium (4.8 log CFU cm-2), showing a strong correlation with post-digestion viability. Overall, microalgal proteins, particularly SPI, govern the interplay between cryogel structure, physical state, and colloidal behaviour. This allows for high lyoprotection, prolonged shelf-life, and improved gastrointestinal survivability and cell adhesion properties, matching or exceeding those of conventional lyophilised microcarriers.

Cellulose nanofibrils (CNFs) possess desirable properties, including low density, high tensile strength, large surface area, and high biodegradability, making them valuable for broad industrial applications. High-pressure homogenization is the most common processing method to produce CNFs. This study reports on the impact of ultra-high-pressure homogenization (UHPH) on the structural and technofunctional properties of CNFs, including their Pickering o/w emulsion stabilizing performance. Microcrystalline cellulose suspensions (0.5 % w/w) were processed at pressures ranging from 500 to 3500 bar for up to 25 passes. According to our findings, the size (fiber length and width) of the CNFs was reduced with pressure increase. The highest colloidal stability of cellulose suspensions was observed at >= 2500 bar for at least 5 passes. The viscosity of cellulose suspensions increased progressively with the severity of the UHPH. Dynamic rheological characterization of the cellulose suspensions processed for 25 cycles revealed a true gel-like behavior within the linear viscoelastic regime and a strain stiffening effect at large strains (> 10 %). The lipid droplet polydispersity and creaming index of Pickering emulsions were minimized using the 3500 bar processed CNFs. In conclusion, UHPH is an efficient method to induce the nanofibrillation of cellulose, and improve its techno-functionality.

OBJECTIVE:Solar irradiation can lead to harmful effects such as skin ageing and cancer. Therefore, the aim of this work was to provide a better understanding of the skin composition and the molecular mechanisms underlying solar-induced damage. METHODS:We measured the impact of sun exposure on the lipidome of a 3D reconstructed human epithelial (RHE) in vitro model, as well as the protective role of a commercial SPF50+ sunscreen on the lipid modulations. MALDI-MSI was used to locate several lipids identified using LC-MS/MS to determine changes in their distribution in the epidermis. RESULTS:There were 252 lipids in RHE models deregulated by irradiation, including multiple phospholipid classes, triacylglycerols, diacylglycerols, sphingolipids, and ceramides. Of these, only four were still modulated when the sunscreen was applied prior to irradiation. MALDI-MSI imaging of control RHE sections alongside optical images detected 4115 lipids which were tentatively identified using the LipidMaps database associated with distinct areas in the tissue. One key lipid linked to keratinocyte differentiation during photoaging, 25-hydroxycholesterol, was present in low levels in control RHE models but increased significantly after irradiation. The increase was prevented by applying sunscreen prior to irradiation. CONCLUSION:A combination of LC-MS/MS and MALDI-MSI enabled the analysis of lipids involved in key pathways altered by irradiation, as well as their location in the epidermis. Importantly, the SPF50+ sunscreen exhibited a protective effect on the epidermis lipidome against modulations due to irradiation. This technology will enable biomarker and pathway-specific events in the epidermis to be monitored after different treatments.

Together with bimetallic systems, metalates derived from anionic nucleophile-activated monometallic systems have shown very high catalytic performances for polycarbonates in epoxide-CO2 copolymerization. However, examples of isolated metalates are rather scarce. Lately, a putative initiating hafnium "ate" species was isolated upon the addition of [PPN]Cl to the N-heterocyclic carbene (NHC) complex of hafnium [PPN][({kappa 3-O,C,O}-NHC)HfCl3] 3-Hf. Inspired by this lead, Ti and Zr "ate" analogues of 3-Hf, 3-Ti and 3-Zr, respectively, were synthesized. All the "ate" complexes exhibited high activity (TOF approximate to 363 h-1) and polycarbonate selectivity (>= 99%) in the copolymerization of cyclohexene oxide (CHO) and CO2 under mild conditions. Monitoring the ring-opening of CHO at room temperature with 3-Hf revealed the rapid formation of a rare metalate intermediate, [PPN][({kappa 3-O,C,O}-NHC)HfCl2(OC6H10Cl)] 5-Hf. Under similar conditions, excess addition of CHO to 3-Hf formed a CHO adduct of 5-Hf species (6-Hf) and at 80 degrees C led further toward another metalate intermediate, [PPN][({kappa 3-O,C,O}-NHC)HfCl(OC6H10Cl)2] 7-Hf. Kinetic studies revealed the first-order dependence in both the catalyst and CHO concentrations and zero-order dependence in CO2 with a Gibbs free energy of 24.4 kcalmol-1 at 80 degrees C. DFT calculations performed on the catalytic system suggest 7-Hf to be one of the key active catalytic species favoring CO2 insertion during copolymerization.

Perovskite solar cells (PSCs) are among the most promising photovoltaic technologies owing to their exceptional optoelectronic properties1,2. However, the lower efficiency, poor stability and reproducibility issues of large-area PSCs compared with laboratory-scale PSCs are notable drawbacks that hinder their commercialization3. Here we report a synergistic dopant-additive combination strategy using methylammonium chloride (MACl) as the dopant and a Lewis-basic ionic-liquid additive, 1,3-bis(cyanomethyl)imidazolium chloride ([Bcmim]Cl). This strategy effectively inhibits the degradation of the perovskite precursor solution (PPS), suppresses the aggregation of MACl and results in phase-homogeneous and stable perovskite films with high crystallinity and fewer defects. This approach enabled the fabrication of perovskite solar modules (PSMs) that achieved a certified efficiency of 23.30% and ultimately stabilized at 22.97% over a 27.22-cm2 aperture area, marking the highest certified PSM performance. Furthermore, the PSMs showed long-term operational stability, maintaining 94.66% of the initial efficiency after 1,000 h under continuous one-sun illumination at room temperature. The interaction between [Bcmim]Cl and MACl was extensively studied to unravel the mechanism leading to an enhancement of device properties. Our approach holds substantial promise for bridging the benchtop-to-rooftop gap and advancing the production and commercialization of large-area perovskite photovoltaics.

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) has become an important tool for skin analysis, as it allows the simultaneous detection and localization of diverse molecular species within a sample. The use of in vivo and ex vivo human skin models is costly and presents ethical issues; therefore, reconstructed human epidermis (RHE) models, which mimic the upper part of native human skin, represent a suitable alternative to investigate adverse effects of chemicals applied to the skin. However, there are few publications investigating the feasibility of using MALDI MSI on RHE models. Therefore, the aim of this study was to investigate the effect of sample preparation techniques, i.e., substrate, sample thickness, washing, and matrix recrystallization, on the quality of MALDI MSI for lipids analysis of the SkinEthic RHE model. Images were generated using an atmospheric pressure MALDI source coupled to a high-resolution mass spectrometer with a pixel size of 5 μm. Masses detected in a defined region of interest were analyzed and annotated using the LipostarMSI platform. The results indicated that the combination of (1) coated metallic substrates, such as APTES-coated stainless-steel plates, (2) tissue sections of 6 μm thickness, and (3) aqueous washing before HCCA matrix spraying (without recrystallization), resulted in images with a significant signal intensity as well as numerous m/z values. This refined methodology using AP-MALDI coupled to a high-resolution mass spectrometer should improve the current sample preparation workflow to evaluate changes in skin composition after application of dermatocosmetics.

Mass spectrometry imaging is a technique uniquely suited to localize and identify lipids in a tissue sample. Using an atmospheric pressure (AP-) matrix-assisted laser desorption ionization (MALDI) source coupled to an Orbitrap Elite, numerous lipid locations and structures can be determined in high mass resolution spectra and at cellular spatial resolution, but careful sample preparation is necessary. We tested 11 protocols on serial brain sections for the commonly used MALDI matrices CHCA, norharmane, DHB, DHAP, THAP, and DAN in combination with tissue washing and matrix additives to determine the lipid coverage, signal intensity, and spatial resolution achievable with AP-MALDI. In positive-ion mode, the most lipids could be detected with CHCA and THAP, while THAP and DAN without additional treatment offered the best signal intensities. In negative-ion mode, DAN showed the best lipid coverage and DHAP performed superiorly for gangliosides. DHB produced intense cholesterol signals in the white matter. One hundred fifty-five lipids were assigned in positive-ion mode (THAP) and 137 in negative-ion mode (DAN), and 76 peaks were identified using on-tissue tandem-MS. The spatial resolution achievable with DAN was 10 μm, confirmed with on tissue line-scans. This enabled the association of lipid species to single neurons in AP-MALDI images. The results show that the performance of AP-MALDI is comparable to vacuum MALDI techniques for lipid imaging.

In this work, the use of Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) was explored as a technique for monitoring the interfacial retro Diels–Alder (retro DA) reaction occurring on well-controlled self-assembled monolayers (SAMs). A molecule containing a Diels–Alder (DA) adduct was grafted on to the monolayers, then the surface was heated at different temperatures to follow the reaction conversion. A TOF-SIMS analysis of the surface allowed the detection of a fragment from the molecule, which is released from the surface when retro DA reaction occurs. Hence, by monitoring the decay of this fragment’s peak integral, the reaction conversion could be determined in function of the time and for different temperatures. The viability of this method was then discussed in comparison with the results obtained by 1H NMR spectroscopy.

The growth process of zinc oxide (ZnO) thin films by atomic layer deposition (ALD) accompanied by the presence of oxygen gas pulsing is investigated by means of the isotopic tracking of oxygen 18O from the water precursor and oxygen 16O from the gas.

Several clinical studies have reported the benefit of the administration of Mesenchymal Stem Cells (MSCs) in cell therapies. However, their routine applications need new substrates to amplify MSCs in vitro according to Good Manufacturing Practices (GMP) conditions and microcarriers are particularly suited for these purposes. In order to optimize the surface properties of Cytodex I microcarriers (Cyt), poly N-isopropylacrylamide (pNIPAM) has been grafted on their surface to promote MSCs adhesion, proliferation, but also to control their detachment by a decrease in temperature. The polymer coating generated on the microcarriers was analyzed using Time-of-Flight, Nanoscale Secondary Ion Mass Spectrometry, and Atomic Force Microscopy. We have confirmed the success of the pNIPAM grafting on Cyt with a two-steps reaction and correlated the influence on matrix functionalization in the function of the organic solvent used to disperse the microcarriers. The effects of pNIPAM functionalization have been explored on Wharton's jelly-MSCs (WJ-MSCs) culture and cell thermal detachment was monitored with fluorescent microscopy. The in vitro results have indicated that WJ-MSCs have a better growth on Cyt-pNIPAM. However, pNIPAM thermal cell detachment was lower than trypsinization, implying that the minimum effective molecular weight and surface density of polymer chains have still to be future optimized.

In this study, dimethylacrylamide (DMA) homopolymer and DMA/ethylene glycol dimethacrylate (DMA/EGDMA) copolymers are produced by an atmospheric pulsed plasma deposition technique. Such a mild deposition method is used to limit monomer fragmentations and favor cross-linked structures formed through the unsaturated carbon double bond polymerization. The kinetics of deposition, and the dependence of the chemical and physical properties of the films on the comonomer ratio are investigated by combining surface and volume-sensitive techniques. In addition, water-stable catechol-bearing terpolymer films are easily produced from a precursor mixture composed of dopamine methacrylamide dissolved in a 50 mol% DMA/EGDMA solution. Finally, it is demonstrated that the developed coatings can be exploited for efficient one-step bioconjugation reaction for potential biological applications.

During the first stages of Atomic Layer Deposition (ALD) of Al2O3 on silicon (Si), the substrate nature affects the surface chemistry, leading to an initial island growth mode. Furthermore, an interfacial zone develops between the Si surface and the dielectric, thus damaging the physical properties of the deposited structure. In this work, these two main shortcomings are investigated for the ALD of Al2O3 films on Si from TMA and H2O. The film and the interfacial zone are characterized by a complete range of techniques, including XRR, TEM, XPS, EDX and ToF-SIMS. In parallel, a computational model is developed to study the initial nucleation and growth steps of the film. An induction period is experimentally evidenced and numerically reproduced, together with the island growth and coalescence phenomena. The chemical composition of the (Al, O, Si) interfacial layer is precisely analyzed to get insight in the mechanisms of its formation. We show that Si oxidation occurs during the island growth, catalyzed by the presence of Al, while it is also fed by species interdiffusion through the ALD film.

Efficient surface functionalization with polydopamine (PDA) films can be easily achieved on virtually any object via single immersion in slightly basic dopamine solutions. In such conditions, however, poor homogeneity, low thickness, and long time of reaction are usually the major limitations. Herein, we report a rational entry to the control of PDA deposition via chemical oxidation under slightly acidic conditions (pH 5.0) ensuring inhibition of uncontrolled autoxidation processes to gain insight about the reaction mechanism and the impact of oxidation conditions on PDA structure. Comparative chemical analysis of dopamine oxidation with three different oxidants (ammonium peroxodisulfate, sodium periodate, and copper sulfate) revealed significant differences in the reaction course and allowed selection of periodate for the fast and homogeneous deposition of PDA films with thickness never before reported. Notably, PDA coatings with unprecedented superhydrophilic/superoleophobic properties were obtained under conditions of high periodate concentration due to degradation of quinone units to yield carboxyl functions. Moreover, these films still present biocompatibility and metal cation reduction properties. Overall, these results provide a novel rational methodology to tailor PDA coatings for technological applications based on periodate control over dopamine polymerization and postsynthetic functional group modification.

Being able to predict the output power of solar cells by analysis of only the first semiconductor layer – commonly called the absorber layer – i.e. before a number of further deposition steps are carried out – would be a clear advantage both at academic research level and for process monitoring in industry. Since the absorber layer is normally the most difficult to fabricate, the hypothesis is that the power conversion efficiency of the solid-state device is dominated by its optoelectronic properties. One option that allows extracting information on the absorber optoelectronic properties is by formation and interrogation of virtually reversible electrolyte (Schottky) junctions 1. We have recently shown that the short circuit current density and thus efficiency of Cu(In,Ga)Se2 solid-state devices can be predicted by measuring the electrochemical photocurrent density of the respective absorber layers in the presence of Eu3+ under illumination 2. In such a system the Eu3+acts as a scavenger for the electrons generated on the p-type semiconductor upon irradiation with photons with energy greater than the semiconductor band-gap. However, this correlation was found complicated by surface non-ideality, leading in some cases to pronounced charge-carrier recombination. Therefore, here we explore an alternative relationship. Similarly to p-n junctions, the electrical behavior vs bias of p-semiconductor/electrolyte junctions is a direct consequence of the energy-barriers for hole transfer 3. As such, the current-voltage dependence can be expressed by the diode equation 4, including the contribution of parasitic shunt paths (Eq. 1). Eq. 1 JD,L = JPh + J0(exp(-eΔV/kT)-1) + ΔV/RSh where JD,L are the dark and illuminated electrical current-density, JPh is the photocurrent density ( = 0 in the dark and < 0 under illumination), J0 is the reverse saturation current, e is the elementary charge, ΔV is the applied voltage, k is the Boltzmann constant, T is the absolute temperature and RSh is the shunt resistance of the solar cell. The dark-current in reverse bias is related to the parasitic terms RSh and J0, with RSh normally dominating. For good solid-state devices RSh should be as large as possible and J0 as small as possible. From inspection of literature solid-state device data the J0 term is more important in determining the overall efficiency of a device than RSh. However, J0 cannot be distinguished from RShin reverse bias, while in forward bias it is possible. Eu2+ ions are required to interrogate the junction in forward bias. Eu2+ acts as an electron donor in the system, revealing the ability of the semiconductor film to accept electrons when kept under forward bias. Due to the exponential term in Eq. 1, the higher this ability to accept electrons, the higher the expected reverse saturation current from such a semiconductor in a full device whilst the effect of RShis negligible. In this work we demonstrate that the reverse saturation current of CuInSe2 solar cell devices can be predicted by measuring their forward bias characteristics in the presence of Eu2+/3+, allowing the prediction of final solid-state device efficiency. To this end a series of CuInSe2 absorber layers were prepared by intentional deviation from a physical vapour deposition routine and they were split into two. Half were completed into solar cell devices and the other half were tested electrochemically. The chosen absorber layers gave solid-state device power conversion efficiencies between 6 and 12.5% 5. The electrochemical experiments consisted of voltammetric analyses in the dark with Eu2+/3+species. The extraction of a term electrochemically-equivalent to the reverse saturation current density is obtained by linear extrapolation of the forward dark current density to voltages close to the open circuit voltage of the semiconductor-electrolyte junction in the dark. Such electrochemically extracted saturation current is compared with the solid-state device saturation current. These findings open the way to a more reliable electrochemically-based estimation of thin film semiconductor properties with a clear link with solid-state device physics. A comparison between this proposed method and the method involving the measurement of the electrochemical photocurrent density will be made. References 1. Peter, L. M., Semiconductor Electrochemistry. Encyclopedia of Life Support Systems: Oxford, 2010. 2. Colombara, D. et al. Electrochemistry Communications 2014, 48, 99-102. 3. Tan, M. X. et al. Progress in Inorganic Chemistry, John Wiley & Sons, Inc.: 2007; pp 21-144. 4. Shockley, W. Bell System Technical Journal 1949, 28, 435-489. 5. Depredurand, V. et al. PVSC Proceedings, 2011 37th IEEE, 19-24 June 2011; 2011; pp 000337-000342. Acknowledgements LPV, LEM, Nexcis team members and Prof. Laurence M. Peter are acknowledged for help and discussion. Funding was provided by the European Commission through the "Scalenano" program (grant agreement nº 284486)/

Polydopamine (PDA) coatings appear as a universal functionalization methodology allowing to coat the surface of almost all kinds of known materials with a conformal, stable, robust and reactive material. Relatively few investigations were dedicated to the incorporation of other molecules in PDA coatings during their deposition from dopamine solutions under oxidative conditions. Herein we rely on the assumption that the basic building blocks of PDA could be porphyrin like tetramers (as well as higher order oligomers) of 5,6-dihydroxyindole and we investigate the influence of a cationic Cu(II) phtalocyanine, namely Alcian Blue (AB), on the deposition kinetics and on the properties of PDA films. We demonstrate that AB is indeed incorporated in the PDA films to yield a composite PDA–AB coating displaying the optical features of both PDA and AB. The amount of incorporated dye depends on its concentration in solution. The obtained PDA–AB films have a smaller thickness than their related PDA counterparts, a different morphology and a higher permeability to the anionic hexacyanoferrate redox probe. In addition, the incorporation of AB in the films is not homogeneous through their thickness as inferred by means of X-ray photoelectron spectroscopy. The reason for this interesting finding is discussed on the basis of the interactions between AB and PDA as well as on the basis of the structure of PDA films.

The formation of polydopamine under mild oxidation conditions from dopamine solutions with mechanical agitation leads to the formation of films that can functionalize all kinds of materials. In the absence of stirring of the solution, we report the formation of polydopamine films at the air/water interface (PDA A/W) and suggest that it arises from an homogeneous nucleation process. These films grow two times faster than in solution and can be deposited on hydrophilic or hydrophobic substrates by the Langmuir-Schaeffer technique. Thanks to this new method, porous and hydrophobic materials like polytetrafluoroethylene (PTFE) membranes can be completely covered with a 35 nm thick PDA A/W film after only 3h of reaction. Finally the oxidation of a monomer followed by a polymerization in water is not exclusive to polydopamine since we also transferred polyaniline functional films from the air/water interface to solid substrates. These findings suggest that self-assembly from a solution containing hydrophilic monomers undergoing a chemical transformation (here oxidation and oligomerization) could be a general method to produce films at the liquid/air interface.

Aluminum-copper (Al-Cu) interconnects are of great interest for a variety of electrical applications, such as lithium- ion batteries. In this paper, the effects of thermal and electrical aging on the intermetallic compound growth of laser braze-welded Al-Cu interconnects are reported. Thermal aging was studied in a temperature range from 200 to 500 degrees C for durations between 1 and 120 h. Electrical aging was studied with 200 A direct current application with different polarities and durations between 1 and 24 h. The formation of intermetallic compounds was found to be dependent on the type of aging and, for electrical aging, on the polarity of the current. The growth of intermetallic compounds under the influence of the electric current was distinctly higher than for thermal annealing conditions. The formation of voids at the transition between intermetallic compounds indicates that electromigration may be the main driving force for the accelerated intermetallic growth.