Filippo Mangolini

High-throughput automated testing offers accelerated ways to discover and characterize novel tribological materials. Here, we describe the design of a custom, fully automated, parallelized ball-on-flat reciprocating tribometer capable of performing upward of 1000 friction experiments a day depending on contact conditions. Combinatorial physical vapor deposition was utilized to develop 448 Pt–Au alloy coatings spanning the full binary compositional range. Tribological performance was evaluated in both lab air and dry nitrogen environments, revealing multiparametric dependencies of friction on composition, hardness, reduced modulus, surface roughness, and sputtered atom kinetic energy. In dry nitrogen, ultralow friction coefficients ( µ ss < 0.1) were observed for Pt-rich coatings, with friction strongly influenced by both composition and the kinetic energy of Pt atoms during deposition. The low friction behavior in dry N 2 , attributed to the formation of tribofilms on Pt–Au, highlights the role of deposition conditions on surface tribochemical processes. Lab air sliding experiments showed large variations in friction coefficients (~ 0.2 to 1) across the entire compositional range and no trends with other modalities or modeled deposition atomistics. Benefits of adapting automation and/or parallelization to reduce operator and testing time were explored by calculating the total times for the presented dataset. Systems with parallelized friction probes as well as automated systems are shown to reduce operator time by 99% and testing time by 90% compared to conventional serial testing. This work demonstrates the power of high-throughput tribological methods to generate large, multimodal datasets, paving the way toward self-driving laboratories in tribology that combine mechanistic insights and machine learning-driven materials optimization.

Abstract The quantification of mass transport in thin films is often based on fitting experimental data with analytical solutions. Although there are pertinent exact closed-form solutions for thermal transport in multilayers, those solutions are not used in the mass transport literature. Rather, this literature is dominated by approximate solutions, which involve various simplifying assumptions.This study systematically evaluates the accuracy of four commonly used approximate solutions, using the exact solution for bilayers as the benchmark. The domain of validity of each approximate solution is identified through parametric studies involving dimensionless parameters representing bilayer thicknesses and diffusivities. It is shown that the most commonly used approximate solutions are accurate only in small subdomains of the dimensionless parametric space. In contrast, the best approximate solution, accurate in a large subdomain of the dimensionless parametric space, is rarely used. We advocate for the use of the exact closed-form solution for quantifying mass transport in thin films.

Subtractive nanomanufacturing is essential for high-precision device fabrication, but conventional techniques rely on resource-intensive processes and environmentally hazardous materials. Here, we introduce Optothermal Bubble Etch Lithography (OBEL), a single-step, maskless technique that enables localized, high-resolution patterning with minimal chemical and thermal damage. OBEL uses a low-power continuous-wave laser focused on a gold film to generate microbubbles at the substrate-liquid interface, which locally concentrate etchant ions for spatially selective etching. Solutal Marangoni convection actively removes bubbles and generated debris, yielding clean and sharply defined features. Operating at ultralow etchant concentrations (0.05 M), OBEL achieves complex planar patterns with submicron (∼450 nm) resolution. This environmentally friendly, cost-effective lithography method offers a scalable alternative for micro- and nanoscale fabrication across electronics, photonics, and biomedical applications.

Subtractive nanomanufacturing is essential for high-precision device fabrication, but conventional techniques rely on resource-intensive processes and environmentally hazardous materials. Here, we introduce Optothermal Bubble Etch Lithography (OBEL), a single-step, maskless technique that enables localized, high-resolution patterning with minimal chemical and thermal damage. OBEL uses a low-power continuous-wave laser focused on a gold film to generate microbubbles at the substrate–liquid interface, which locally concentrate etchant ions for spatially selective etching. Solutal Marangoni convection actively removes bubbles and generated debris, yielding clean and sharply defined features. Operating at ultralow etchant concentrations (0.05 M), OBEL achieves complex planar patterns with submicron (∼450 nm) resolution. This environmentally friendly, cost-effective lithography method offers a scalable alternative for micro- and nanoscale fabrication across electronics, photonics, and biomedical applications.

Subtractive nanomanufacturing is essential for high-precision device fabrication, but conventional techniques rely on resource-intensive processes and environmentally hazardous materials. Here, we introduce Optothermal Bubble Etch Lithography (OBEL), a single-step, maskless technique that enables localized, high-resolution patterning with minimal chemical and thermal damage. OBEL uses a low-power continuous-wave laser focused on a gold film to generate microbubbles at the substrate–liquid interface, which locally concentrate etchant ions for spatially selective etching. Solutal Marangoni convection actively removes bubbles and generated debris, yielding clean and sharply defined features. Operating at ultralow etchant concentrations (0.05 M), OBEL achieves complex planar patterns with submicron (∼450 nm) resolution. This environmentally friendly, cost-effective lithography method offers a scalable alternative for micro- and nanoscale fabrication across electronics, photonics, and biomedical applications.

Subtractive nanomanufacturing is essential for high-precision device fabrication, but conventional techniques rely on resource-intensive processes and environmentally hazardous materials. Here, we introduce Optothermal Bubble Etch Lithography (OBEL), a single-step, maskless technique that enables localized, high-resolution patterning with minimal chemical and thermal damage. OBEL uses a low-power continuous-wave laser focused on a gold film to generate microbubbles at the substrate–liquid interface, which locally concentrate etchant ions for spatially selective etching. Solutal Marangoni convection actively removes bubbles and generated debris, yielding clean and sharply defined features. Operating at ultralow etchant concentrations (0.05 M), OBEL achieves complex planar patterns with submicron (∼450 nm) resolution. This environmentally friendly, cost-effective lithography method offers a scalable alternative for micro- and nanoscale fabrication across electronics, photonics, and biomedical applications.

Salt-in-ionic liquids (SiILs) are promising electrolytes for batteries. This study reveals how water affects the nanostructure, surface forces, and electrochemical properties of sodium-SiILs with bis(trifluoromethanesulfonyl)imide ([TFSI] − ) using experiments and molecular dynamics simulations. Dry sodium-SiILs exhibit long-range repulsive forces that deviate from classical electrostatics and are influenced by surface-induced aggregation of nanoscale ionic clusters. Addition of water reduces cluster size and order, yielding force profiles more similar to neat ILs. Atomic force microscopy shows water-induced cluster reorganization near negatively charged surfaces. Water-in-SiILs exhibit increased capacitance and a shift from camel- to bell-shaped profiles, indicating a fundamental change in the double layer, while enhancing conductivity and maintaining a wide electrochemical stability window. These findings underscore the sensitivity of the SiIL nanostructure to hydration from bulk to interface and its critical role in electrochemical properties. Advances in the understanding of the interplay between the nanostructure and screening are essential for the rational design of the solid electrolyte interphase, a crucial component dictating battery performance and safety.

Dust contamination is a key challenge for deployment of optics in harsh environments, maintenance of photovoltaics, and the pursuit of sustainable interplanetary exploration. In this work, the dust mitigation properties of nanostructured substrates with thin insulating and conductive coatings are investigated. To examine the contribution of capillary, electrostatic, and van der Waals forces to the surface's overall dust adhesion, the relative humidity is varied to control their relative contributions. Experiments show that samples with conductive coatings can have up to 91.0% less coverage than insulating sample under low humidity. The results indicate that the electrical properties of surface coatings play a significant role in mitigating dust adhesion forces at low humidities, where electrostatic forces dominate. In addition, reduced surface energy and nanostructured features are key for an improved anti-dust performance at all humidities. The results demonstrate that the nanostructure with conductive coatings is highly anti-dust and has less than 2.5% percentage area coverage throughout the humidity range. This research improves understanding of the interparticle forces between substrate and particulate and explores viable alterations of surface geometry and chemistry for passive dust mitigation that are applicable across a broad humidity range.

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is widely used for surface-sensitive identification of polymeric materials. Yet, the interpretation of ToF-SIMS spectra acquired on polymers can be hindered by secondary ion fragmentation and the lack of reference spectra acquired under comparable conditions. Here, we report the ToF-SIMS reference spectra in positive mode for three common, additive-free homopolymer films: polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET). The specimens were commercially available, biaxially oriented films and stored dry prior to analysis; immediately before loading the sample, each surface was freshly scraped to expose a pristine region. Data collection was performed on an IONTOF M6 using a 30 keV Bi+ liquid metal ion gun in pulsed, bunched mode under static SIMS conditions (1 × 1012 ions/cm2). Data were acquired from 100 × 100 μm2 areas (256 × 256 pixels) at 300 K under high vacuum with electron flood charge compensation. The resulting spectra provide diagnostic polymer fingerprints, including hydrocarbon allylic fragment series for PP, aromatic and styrenic fragments for PS, and oxygenated aromatic/terephthalate fragments and repeat-unit oligomer ions for PET. These spectra are intended to serve as baseline library entries to support polymer identification, method development, and routine quality control in ToF-SIMS surface analysis.

Secondary Ion Mass Spectrometry (SIMS) is a powerful technique for investigating diffusion at and near material surfaces. It directly measures the intensity of secondary ions ejected upon ion beam bombardment of sample surfaces. In SIMS diffusion studies, three concentration proxies rather than intensities are often employed. Using the classical diffusion equation as the basis, we establish conditions under which each proxy is acceptable for extracting diffusivities. We demonstrate that these conditions depend on the temporal and spatial evolution of the intensity of the reference secondary ion. Further, these conditions may or may not be realized in experiments, regardless of the chemical potential landscape of the matrix. We advocate for reporting raw data as is, i.e ., in terms of intensities of ejected ions.

Positive Spectrum of PS

Positive Spectrum of PS

Positive Spectrum of PET

Positive Spectrum of PP

Positive Spectrum of PP

Positive Spectrum of PET

Time-of-Flight Secondary Ion Mass Spectrometry (ToF‑SIMS) is widely used for surface-sensitive identification of polymeric materials. Yet, the interpretation of ToF-SIMS spectra acquired on polymers can be hindered by secondary ion fragmentation and the lack of reference spectra acquired under comparable conditions. Here, we report the ToF‑SIMS reference spectra in positive mode for three common, additive‑free homopolymer films: polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET). The specimens were commercially-available, biaxially-oriented films and stored dry prior to analysis; immediately before loading the sample, each surface was freshly scraped to expose a pristine region. Data collection was performed on an IONTOF M6 using a 30 keV Bi⁺ liquid metal ion gun in pulsed, bunched mode under static SIMS conditions (1 × 10¹² ions/cm²). Data were acquired from 100 µm × 100 µm areas (256 × 256 pixels) at 300 K under high vacuum with electron flood charge compensation. The resulting spectra provide diagnostic polymer fingerprints, including hydrocarbon allylic fragment series for PP, aromatic and styrenic fragments for PS, and oxygenated aromatic/terephthalate fragments and repeat‑unit oligomer ions for PET. These spectra are intended to serve as baseline library entries to support polymer identification, method development, and routine quality control in ToF‑SIMS surface analysis.

Positive Spectrum of PET

Positive Spectrum of PS

Positive Spectrum of PP

Positive Spectrum of PP

Positive Spectrum of PS

Positive Spectrum of PET

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a powerful surface-analytical method extensively used in a variety of scientific fields and industrial sectors. However, quantitative ToF-SIMS analyses are challenging and limit the broader applicability of this characterization technique. This study demonstrates the use of the full spectrum method (FSM) as a quantitative technique for analyzing homopolymers (e.g., polypropylene (PP), polystyrene (PS), and polytetrafluoroethylene (PTFE)) using ToF-SIMS. By analyzing the entire collection of sputtered secondary ions, FSM minimizes "matrix effects" that commonly impede the quantitative ToF-SIMS analysis of polymers. The results indicate that the acquisition of ToF-SIMS data should be carried out while varying the primary ion fluence. This approach yields experimental data that can be directly compared with theoretical predictions of ion-induced surface damage, thus providing unambiguous evidence for the effect of ion bombardment and whether the quantification was performed with clusters whose intensity is affected by ion-induced damage. Overall, the outcomes of this work establish FSM as a powerful tool for multicomponent analysis, advancing the precise surface characterization of polymeric materials via ToF-SIMS.

In this work, the effect of nanostructures and surface coatings on the effective electrostatic force acting on a particle resting on the surface is investigated. A proposed analytical model based on Coulomb’s law predicts that electrostatic forces on a particle decrease with the addition of nanostructures due to increased separation distance. Additional comsol simulations were utilized to predict interactions with a highly charged surface relative to the particle, and an inverse interaction is seen. In this case, the added surface geometry leads to an increased electrostatic force on the particle due to greater surface area and charge concentration at structure peaks. Planar and nanostructured polycarbonate surfaces coated with Al2O3, TiO2, Pt, or left bare are contaminated with lunar dust simulant and charged with an electron beam to confirm these predictions. The number of ejected dust particles when a charge is applied is quantified for each of these samples and compared to the initial predictions. The addition of nanostructures on the highly charging polycarbonate substrate led to a doubling of the frequency of particle removal, whereas the low charging Al2O3 and TiO2 samples saw a tenfold decrease in particle removal. By engineering tunable surface responses to electrostatic forces, dust mitigating surfaces will be designed for enhanced performance in charge inducing enviroments, such as the lunar surface.

Abstract Global energy losses and CO2 emissions are largely caused by wear and friction in mechanical systems. These effects can be lessened, and energy efficiency increased by developing advanced lubricants. This work investigates the addition of three choline-based amino acid protic ionic liquids (CHAAPILs), which are environmentally friendly and bioderived, to a low-viscosity, non-polar polyalphaolefin (PAO) base oil. To evaluate the friction and wear performance of the lubricants, tribological experiments were carried out using 52100 steel ball-on-disk setups under boundary lubrication conditions. Optical microscopy, 3D profilometry, SEM, EDS, and Raman spectroscopy were used to characterize the worn surface and get insights into the wear mechanism. The results reveal that adding 1 wt.% of CHAAPILs to PAO reduced the coefficient of friction. Choline-Aspartic acid ([CHO][ASP]) had the largest reduction (around 26%) and the lowest wear volume. The structure of the amino acid anion was found to have a major impact on the lubricating property – IL having stronger polarity exhibit superior surface protection. The crucial function of molecular structure was highlighted by the fact that PAO + [CHO][ASP] revealed better lubricating behavior. Surface investigations conducted after the test showed that the development of protective tribochemical films was linked to better performance. The study shows that CHAAPILs have the potential of improving the tribological performance of non-polar oils when used as additives, hence aiding initiatives to lower energy consumption and environmental effects.

a, the average absolute deviation of the height from the mean line (at some, not necessarily known or specified, lateral length scale). However, other parameters, particularly those that are scale-dependent, influence surface and interfacial properties; for example the local surface slope is critical for visual appearance, friction, and wear. The present Surface-Topography Challenge was launched to raise awareness for the need of a multi-scale description, but also to assess the reliability of different metrology techniques. In the resulting international collaborative effort, 153 scientists and engineers from 64 research groups and companies across 20 countries characterized statistically equivalent samples from two different surfaces: a "rough" and a "smooth" surface. The results of the 2088 measurements constitute the most comprehensive surface description ever compiled. We find wide disagreement across measurements and techniques when the lateral scale of the measurement is ignored. Consensus is established through scale-dependent parameters while removing data that violates an established resolution criterion and deviates from the majority measurements at each length scale. Our findings suggest best practices for characterizing and specifying topography. The public release of the accumulated data and presented analyses enables global reuse for further scientific investigation and benchmarking. Supplementary Information: The online version contains supplementary material available at 10.1007/s11249-025-02014-y.

HYPOTHESIS Understanding the structure of ionic liquids (ILs) near solid surfaces is essential for advancing their implementation in engineering applications, including as electrolytes in energy storage devices and lubricants. The structure of IL/solid interfaces has extensively been evaluated through scanning probe microscopy and surface force apparatus measurements; however, these techniques only probe the static interfacial properties of ILs when nanoconfined between two solid surfaces. The underpinning hypothesis of this work is that dynamic wetting is an effective method for gaining insights into the structure of IL/solid interfaces and drawing links between the IL architecture and their interfacial behavior without nanoconfinement between two surfaces. EXPERIMENT Sessile drop dynamic wetting measurements were conducted to assess the static and dynamic interfacial structure of a homologous series of ILs, which contain cations with varying alkyl chain length, on oxidized silicon. The dynamic wetting data were modeled using the molecular kinetic theory. FINDINGS The dynamic wetting results revealed that the jump length of the IL ions at the three-phase contact line decreases with increasing cation alkyl chain length. This finding indicates a progressive change in interfacial ion organization, with cations increasingly oriented perpendicularly to the substrate, as the cation alkyl chain length increases, allowing for a higher surface packing density. Furthermore, the viscosity of ILs was found to significantly increase (58-105×) near the solid surface, particularly for ILs with cations containing short alkyl chains. The results of this work advance our understanding of the structural and dynamic properties of ILs near solid surfaces.

o Increased oxygen content with increasing contact pressure indicate passivation of broken bonds during the sliding process Chemical Bonding o Ultra-low friction is notably achievable when tribofilms contain a relatively high fraction of sp 2 bonded carbon (>0.2) and low oxygen content DLC or Polymer?o Hydrogen quantification and AFM analysis suggest the formation of an increasingly polymer-like material with contact pressure

The quantitative evaluation of the carbon hybridization state by x-ray photoelectron spectroscopy (XPS) has been a surface-analysis problem for the last three decades due to the challenges associated with the unambiguous identification of the characteristic binding energy values for <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:msup> <a:mrow> <a:mi>sp</a:mi> </a:mrow> <a:mn>2</a:mn> </a:msup> </a:math> - and <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"> <b:msup> <b:mrow> <b:mi>sp</b:mi> </b:mrow> <b:mn>3</b:mn> </b:msup> </b:math> -bonded carbon. Here, we computed the binding energy values of C(1s) core electrons on the absolute energy scale for model structures of amorphous carbon (a-C) using density functional theory (DFT). The DFT calculations show that in the case of hydrogen-free a-C, the C(1s) binding energy for <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"> <c:msup> <c:mrow> <c:mi>sp</c:mi> </c:mrow> <c:mn>3</c:mn> </c:msup> </c:math> carbon atoms is a distribution found approximately 1 eV higher than the binding energy distribution of <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"> <d:msup> <d:mrow> <d:mi>sp</d:mi> </d:mrow> <d:mn>2</d:mn> </d:msup> </d:math> -hybridized carbons. However, the introduction of hydrogen in the a-C network reduces the distance between the characteristic signals of <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"> <e:msup> <e:mrow> <e:mi>sp</e:mi> </e:mrow> <e:mn>3</e:mn> </e:msup> </e:math> - and <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"> <f:msup> <f:mrow> <f:mi>sp</f:mi> </f:mrow> <f:mn>2</f:mn> </f:msup> </f:math> -bonded carbon due to the increased ability to screen the core hole by neighboring hydrogen atoms as compared to carbon atoms. This effect hinders the unambiguous quantification of the carbon hybridization state on the basis of C(1s) XPS data alone. This work can assist surface scientists in the use of XPS for the accurate characterization of carbon-based materials.