Evaporation Regime Research Articles

Lyotropic Liquid Crystal Mediated Assembly of Donor Polymers Enhances Efficiency and Stability of Blade-Coated Organic Solar Cells.

Conjugated polymers can undergo complex, concentration-dependent self-assembly during solution processing, yet little is known about its impact on film morphology and device performance of organic solar cells. Herein, lyotropic liquid crystal (LLC) mediated assembly across multiple conjugated polymers is reported, which generally gives rise to improved device performance of blade-coated non-fullerene bulk heterojunction solar cells. Using D18 as a model system, the formation mechanism of LLC is unveiled employing solution X-ray scattering and microscopic imaging tools: D18 first aggregates into semicrystalline nanofibers, then assemble into achiral nematic LLC which goes through symmetry breaking to yield a chiral twist-bent LLC. The assembly pathway is driven by increasing solution concentration - a common driving force during evaporative assembly relevant to scalable manufacturing. This assembly pathway can be largely modulated by coating regimes to give 1) lyotropic liquid crystalline assembly in the evaporation regime and 2) random fiber aggregation pathway in the Landau-Levich regime. The chiral liquid crystalline assembly pathway resulted in films with crystallinity 2.63 times that of films from the random fiber aggregation pathway, significantly enhancing the T80 lifetime by 50-fold. The generality of LLC-mediated assembly and enhanced device performance is further validated using polythiophene and quinoxaline-based donor polymers.

Disentangling the Impacts of Environmental Factors on Evaporative Fraction Across Climate Regimes

AbstractEvaporative fraction (EF) is a useful measure for quantifying land surface energy partitioning processes and determining evaporative regimes; however, its influencing factors remain highly uncertain. Here, global data sets were compiled to disentangle the effects of environmental variables on EF variations along climate and land surface gradients. We found that (a) at annual timescales, ecosystem‐level EF could be expressed as a power law function of aridity index. The relationships of mean annual soil water content (SWC) and leaf area index (LAI) with mean annual EF resembled the traditional evaporative regime theory; (b) at daily timescales, the boosted regression tree method quantitatively revealed that the impacts of environmental variables (including meteorological variables) on EF showed equal importance, especially at humid sites, primarily due to the different response direction and magnitude of latent heat (LE) and sensible heat (H) fluxes to environmental changes. Particularly, the contrasting responses of LE (positive) and H (negative) to SWC, LAI, and relative humidity enhanced the positive effects of those influencing variables on EF; whereas, the correlations between EF and energy‐related factors (i.e., net radiation‐Rn and air temperature‐Ta) deteriorated as both LE and H showed positive response patterns to those variables; (c) meteorological factors were also found to have nonlinear effects on daily EF, further modified by climatic conditions. Rn near 150 W/m2 and Ta near 15°C appeared to be important energy‐partitioning thresholds at drier and humid sites, respectively. Moreover, changing interactions among environmental variables with climates were demonstrated to be important for better explaining EF variations.

Stability analysis of volatile liquid films in different evaporation regimes

Stability analysis of volatile liquid films in different evaporation regimes

Ambient-gas forced convection dictated evaporation kinetics of generic sessile droplets

We probe the temporal evolution of internal thermo-hydrodynamic features of evaporating sessile droplets under external forced convection. A transient numerical model based on Arbitrary Lagrangian-Eulerian (ALE) framework is adopted. The governing equations corresponding to the transport phenomena (mass, momentum and energy) are solved in a fully coupled manner in both the droplet (liquid) and ambient (gaseous) domains while accurately tracing the droplet interface evolution. The role of initial wetting state, external convection velocity and convective heating/cooling effects due to the air-flow are explored in details, and good agreements are noted with previous reports from literature. Results show that although the evaporation rate is augmented significantly in forced convection conditions, the same does not increase in proportion at higher Reynolds numbers. This is primarily due to the enhanced cooling effects that reduce saturated vapor concentration at droplet surface, and thereby supress the diffusion mechanism. Also, depending upon the contact angle, the evaporative cooling effects are compensated partially or completely due to convective heating. This altered thermal profile substantially influences internal hydrodynamic features (Marangoni flow and heat advection) during the transient and stable regimes of droplet evaporation. At higher degrees of convective heating, the droplet interface temperature becomes higher than its base temperature. This condition results in a completely opposite internal Marangoni vortex at stable state compared to that induced due to evaporative cooling effects. We also provide a regime map to show the role of the gas-phase Stefan number on the droplet-phase hydrodynamic regimes.

Net evaporation-induced mangrove area loss across low-lying Caribbean islands

Abstract Although mangroves provide many beneficial ecosystem services, such as blue carbon storage and coastal protection, they are currently under threat due to changes in climate conditions, such as prolonged drought exposure. Under drought conditions, evaporation exceeds precipitation and high soil salinities can lead to stunted growth and die-back. To quantify this interplay, we developed a database for low-lying and uninhabited mangrove islands in the Caribbean under various evaporation and precipitation regimes. We extracted physical and biological information from each island using remote sensing techniques and coupled it with a process-based model. We used this database to develop a model that explains both the spatial variability in vegetated area across the Caribbean—as a function of rates of evaporation and precipitation—and porewater salinity concentration and dispersion from island edge towards the interior of mangrove islands. We then used this validated model to predict mangrove area loss associated with increases in evaporation to precipitation rates by 2100 for different Shared Socioeconomic Pathways (SSP). Less wealthy Caribbean regions such as Belize, Puerto Rico, and Venezuela are disproportionally affected, with mangrove area losses ranging from 3%–7% for SSP 2.6 and 13%–21% for SSP 7.0. Furthermore, foregone carbon sequestration in lost biomass under SSP 4.5 and 7.0 scenarios could compromise the ability of low-lying Caribbean mangrove islands to vertically adjust to sea level rise.

Droplet–droplet vapor-mediated interactions in confined environments

The evaporation of multiple droplets ensues ubiquitously in nature and industry. Vapor mediation caused by evaporating neighboring droplets is a demonstrated phenomenon that shows that droplets can interact with each other via the vapor in both open and confined configurations, i.e., the “shielding effect.” However, interactions between paired droplets in confined environments, more common in industrial processes, remain unexplored. In this Letter, we experimentally investigate the evaporation of water based paired sessile droplets on hydrophilic glass slides at different spacings in the absence and presence of an enclosed chamber. The results demonstrate that a confined environment significantly attenuates droplet evaporation, which intensifies with decreasing spacing between droplets. A 30%–82% increase in the droplet lifetime is found for the shortest distance studied in a confined environment, while results in an open environment are provided as a control. Both the local shielding effect and the global vapor accumulation due to confinement collaboratively induce such strong evaporation suppression. In addition, two well differentiated evaporation regimes ensue in a confined environment where the shielding effect initially dominates the evaporation suppression, whereas confinement governs the later evaporation stage. The later stage accounts for over 60% of the droplet lifetime. Such transition and further evaporation suppression, when compared to the classical shielding effect, highlights the importance of a confined environment in multiple droplet evaporation.

An experimental study of the thermal-hydraulics of a spent nuclear fuel pool under loss-of-cooling accident conditions. Part II: a first interpretation of the MIDI tests

This article provides a first interpretation of the MIDI tests that were conducted in the frame of the IRSN’s DENOPI project. A first-level phenomenological analysis is detailed here. It is shown that the actual phenomenology mostly complies with the one that was envisioned by the community right after the Fukushima-Daiichi nuclear accident. Next, the diverse modes of water vaporization that may come into play during a spent nuclear fuel pool loss-of-cooling accident are quantified for each achieved test, by means of a proposed analytical model of the vapor diffusion process taking place on top of the liquid pool free surface. Then, a so-called vaporization regimes map is reconstructed on the basis of the test data. This map allows predicting the most likely dominant vaporization mode, given the pool level and total heat power. At last, the obtained data is reduced through the form of a set of dimensionless correlations, involving some of the classical numbers in heat and mass transfers. In doing so, the free surface evaporation, degassing of dissolved gaseous species and bubbles release processes are all modeled by means of a simple mathematical formulation.

Numerical investigation of droplet impact and heat transfer on hot substrates under an electric field

In this study, the effects of the electric field on the impact dynamics and heat transfer of a single droplet impinging on hot substrates in the film evaporation regime were numerically investigated with phase-field method. According to the simulation results, many fancy impact behaviors of the droplets under a vertical electric field were observed. A strong electric field was found to induce upward pinch-off or even tiny jet phenomena on the hydrophilic substrates. In contrast, the bouncing droplet on hydrophobic substrate would be vertically stretched before leaving the substrates. The maximum spreading ratio of impacting droplets was always inversely proportional to the applied electric field intensity. Correlations of the maximum spreading for the charged condition were proposed by considering the effects of the electric force. In addition, the total heat transfer from hot substrates to the impacting droplet was verified as closely related to the maximum spreading area, spreading time, and instantaneous local heat flux. However, the broken droplets from the induced tiny jet would eventually fall back to disturb the sessile droplet, enhancing the droplet cooling efficiency. The modified heat transfer model of impacting droplets under the effect of an electric field on hydrophilic substrates was established. Finally, the surface charge distribution and electric force loading of the impacting droplets were also discussed. This work delved deep into the underlings of droplet spreading heat transfer under an electric field, and the main findings promised to advance high-efficiency cooling technology.

Averaged Heat Fluxes Densities During Condensation and Evaporation of a Water Droplet

This study is intended for experimental investigation of the influence of boundary conditions on the intensity of phase transformations and heat transfer processes in a suspended water droplet. The results of the dynamics of the averaged heat fluxes densities during the droplet phase change cycle are presented and analysed. The influence of the droplet initial temperature, the surrounding air flow temperature and the additional humidity in the air flow were defined in separate regimes of the droplet phase transformations cycle. The experiments performed demonstrated that the parameters of the air flow surrounding the suspended water droplet affect the intensity of heat fluxes in the droplet throughout whole its phase change cycle. It was experimentally claimed that the initial temperature of the water droplet has no influence on the droplet heat and mass transfer processes in the equilibrium evaporation regime. The obtained results showed that most intensity heat flux densities are at the beginning of the droplet phase change cycle when condensation process occurs on the droplet’s surface in case with biggest amount of additional humidity in the surrounding air flow. This is very important in technologies of cleaning and heat recovery from flue gases.

Evaporation of binary liquids from a capillary tube

Evaporation of multi-component liquid mixtures in confined geometries, such as capillaries, is crucial in applications such as microfluidics, two-phase cooling devices and inkjet printing. Predicting the behaviour of such systems becomes challenging because evaporation triggers complex spatio-temporal changes in the composition of the mixture. These changes in composition, in turn, affect evaporation. In the present work, we study the evaporation of aqueous glycerol solutions contained as a liquid column in a capillary tube. Experiments and direct numerical simulations show three evaporation regimes characterised by different temporal evolutions of the normalised mass transfer rate (or Sherwood number $Sh$ ), namely $Sh (\tilde{t} ) = 1$ , $Sh \sim 1/\sqrt {\tilde{t} }$ and $Sh \sim \exp (-\tilde{t} )$ , where $\tilde {t}$ is a normalised time. We present a simplistic analytical model that shows that the evaporation dynamics can be expressed by the classical relation $Sh = \exp ( \tilde{t} )\,\mathrm {erfc} ( \sqrt {\tilde{t} })$ . For small and medium $\tilde{t}$ , this expression results in the first and second of the three observed scaling regimes, respectively. This analytical model is formulated in the limit of pure diffusion and when the penetration depth $\delta (t)$ of the diffusion front is much smaller than the length $L(t)$ of the liquid column. When $\delta \approx L$ , finite-length effects lead to $Sh \sim \exp (-\tilde{t} )$ , i.e. the third regime. Finally, we extend our analytical model to incorporate the effect of advection and determine the conditions under which this effect is important. Our results provide fundamental insights into the physics of selective evaporation from a multi-component liquid column.

Estimating Hydrological Regimes from Observational Soil Moisture, Evapotranspiration, and Air Temperature Data

Abstract Evapotranspiration has long been understood to vary with soil moisture in drier regions and to be relatively insensitive to soil moisture in wetter regions. A number of recent studies have quantified this behavior with various model and observational datasets. However, given the disparate approaches and datasets used, uncertainty persists in how the underlying relationships vary in space and time. Here we complement the existing studies by analyzing two datasets as yet untapped for this purpose: a satellite-based evapotranspiration E product retrieved using geostationary thermal imagery and a meteorological-station-based dataset of daily 2-m air temperature (T2M) diurnal amplitudes. Both datasets are analyzed synchronously with soil moisture from the Soil Moisture Active Passive (SMAP) satellite. We thereby derive maps of evaporative regimes that vary in space and time as one might expect, that is, the water-limited regime grows eastward across the conterminous United States as spring moves into summer, only to shrink again going into winter. The relationship between the E and soil moisture data appears particularly tight, which is encouraging given that the E data (like the T2M data) were not constructed using any soil moisture information whatsoever. The general agreement between the two independent sets of results gives us confidence that the generated maps correctly represent, to first order, evaporative regime behavior in nature. The T2M results have the added benefit of highlighting the significant connection between soil moisture and overlying air temperature, a connection relevant to T2M predictability. Significance Statement When a soil is somewhat dry, an increase in soil moisture can lead to an increase in evapotranspiration E. In contrast, when a soil is wet, E is limited instead by the availability of energy. Determining where E is water limited, energy limited, or some combination of both is important because it tells us where accurate soil moisture initialization in a forecast system might contribute to more accurate forecasts of E and thus air temperature. Here we use a combination of independent datasets (satellite-derived estimates of soil moisture and E as well as air temperature measurements from weather stations) to provide new monthly maps of the water-limited, energy-limited, and combination regimes over the continental United States and across the world.

Flow pattern-based heat transfer analysis of microchannel flow boiling: An experimental investigation

The present study investigates the flow boiling heat transfer and flow pattern of R245fa in a smooth, horizontal microchannel with an inner diameter of 1 mm. The experiments cover a range of mass flux from 300 to 700 kg/m2s and heat fluxes varying between 10 and 94 kW/m2, with corresponding saturation temperature of 23–54 °C. Heat transfer experiment results indicate that the local heat transfer coefficient (HTC) presents two distinct variation trends under different heat and mass flux conditions. In addition, the heat flux is positively correlated with the local HTC at each measure point. Visualization experiment results show that annular flow forms at low vapor quality and significantly influences heat transfer as the primary flow pattern. The flow boiling heat transfer of R245fa in the 1 mm microchannel can be characterized by three regimes: bubble/slug regime, liquid film evaporation regime, and intermittent dryout regime. Thin liquid film evaporation and intermittent dryout during annular flow predominately contribute to heat transfer. Finally, the experimental HTC is compared with five different predictive methods, revealing that the three-zone model proposed by Thome et al. [46] holds immense potential for estimating the local HTC in the microchannel.

Quantitative characterization of the pseudo-boiling contribution to supercritical heat transfer

This paper explores the supercritical heat transfer mechanism by characterizing the boiling contribution ratio qb/q, where qb is the boiling heat flux and q is the applied heat flux. Experiments are performed using nickel–chromium wire in 15 °C liquid carbon dioxide at 5.2, 7.6, 9.0, and 11.0 MPa. The evaporation heat flux qe is the amount of heat used for vapor generation, while qb is the heat transfer in the bulk liquid due to the disturbance of the flow/temperature field by vapor–liquid interface motion. A data processing procedure is developed to measure qb/q from the captured images. Similar trends appear for both supercritical pseudo-boiling and subcritical boiling. The evaporation-like regime at supercritical pressures reaches qb/q = 0.21–0.43, while the film boiling (evaporation) regime achieves qb/q = 0.08. In the supercritical-boiling-like regime, qb/q increases sharply from 0.19 to 0.65, whereas in the subcritical-nucleate-boiling regime, qb/q maintains a value of 0.30 followed by a rapid rise to 0.68 under a vigorous bubble merging and departing mechanism. At both subcritical and supercritical pressures, the heat transfer deteriorates in the evaporation regime, but is significantly enhanced by phase-change-induced flow/temperature field perturbations. The boiling curves differ in the two pressure domains. At supercritical pressures, natural convection transitions smoothly to the evaporation-like regime, then to the boiling-like regime. At subcritical pressures, a steep transition from natural convection to nucleate boiling occurs, and then, film boiling is induced through the action of surface tension. The above findings complete the inverse boiling curves in the two pressure domains.

Исследование многолетней изменчивости элементов водного баланса речного бассейна в современном климате

The assessment of changes in the elements of the water balance of the Volga River basin in the formation zone near Volgograd for the entire period of the twentieth century and at the beginning of the first half of the XXI century is considered. The conducted retrospective conjugate analysis of the EWB of the Volga River basin is based on the use of sufficiently long hydro meteorological arrays of initial observation data covering the period 1891/1892‑2020/2021. Two time series of annual and seasonal values of atmospheric precipitation, river runoff, total evaporation of land, changes in basin moisture reserves and changes in surface air temperature of the cold and warm periods and the year as a whole are organized. It was established that until 1935, in the long-term course of the runoff of the Volga River basin, natural factors were of decisive importance, i.e. the nature of the humidification of the territory, the regime of total evaporation from its surface and the change in moisture reserves in the soil-soils. Since 1935, the water content of the river has changed. Human economic activity began to have a significant impact on the Volga, especially the operating modes of the Volga-Kama cascade of waterworks. However, anthropogenic influences do not affect the formation of lateral tributaries, which are controlled by 11 reservoirs of the Volga-Kama cascade. Therefore, for a retrospective conjugate analysis of the EWB of the Volga River basin, two conditionally natural time series of different durations were used

Изотопный состав и условия образования фаменских карбонатолитов Центрально-Хорейверского вала (Хорейверская впадина, Печорская плита)

The article presents results of the distribution of the isotopic composition of 13C and 18O (119 samples) across four facies zones to substantiate the conditions of Famennian carbonation accumulation. The Lower Famennian carbonates of the shoal zone showed values of 13C (1.5 ± 0.15 %), 18O (25.01 ± 0.29 %) reflecting evaporative processes in a shallow basin in a warm and dry climate. For the rocks of the microbial mounds zone, the values of 13C (2.47 ± 1.12 %) and 18O (23.51 ± 1.12 %) reflect an increase in bioproductivity and some fluctuation in water salinity. In the limestones of the zone of transition to depression, the variations of isotopic composition are more distinct in the section. Thus, the Early Famennian is characterized by the average values of 13C (0.94 ± 0.59 %) and 18O (23.73 ± 2.18 %) for marine carbonates. The transition to the Middle Famennian is accompanied by isotopic weighting of 13C (1.30 ± 0.47%) and 18O (24.52 ± 1.45%), which shows an increase in evaporation processes under aridization conditions. In the Late Famennian, the isotopic composition abruptly lightens by 13C (–1.05 ± 0.66 %), which is associated with desalination under conditions of climate humidification. At the same time, the value of 18O (25.75 ± 0.31 %) corresponds to the average values for carbonates of the Devonian. The values of 13C (1.04 ± 0.89 %) and 18O (26.01 ± 0.99 %) in the carbonates of the zone slope of the carbonate bank towards the shallow shelf reflect the conditions of the normal sea basin with a slight increase in the evaporation regime during climate aridization. The obtained results indicate that the Famennian sedimentation basin characterized by fluctuations in sea level, facies, water hydrochemistry and climate.

Evaporation of Small Sessile Drop Deposited on a Horizontal Solid Surface: New Exact Solutions and Approximations

Evaporating a liquid sessile drop deposited on a horizontal surface is an important object of applications (printing technologies, electronics, sensorics, medical diagnostics, hydrophobic coatings, etc.) and theoretical investigations (microfluidics, self-assembly of nanoparticles, crystallization of solutes, etc.). The arsenal of formulas for calculating the slow evaporation of an axisymmetric drop of capillary dimensions deposited on a flat solid surface is reviewed. Characteristics such as vapor density, evaporation flux density, and total evaporation rate are considered. Exact solutions obtained in the framework of the Maxwellian model, in which the evaporation process of the drop is limited by vapor diffusion from the drop surface to the surrounding air, are presented. The summary covers both well-known results obtained during the last decades and new results published by us in the last few years, but practically unknown to the wider scientific community. The newest formulas, not yet published in refereed publications, concerning exact solutions for a number of specific contact angles are also presented. In addition, new approximate solutions are presented (total evaporation rate and mass loss per unit surface area per unit time in the whole range of contact angles θ∈[0, π), drop lifetime in constant contact radius evaporation regime and constant contact angle mode), which can be used in modeling without requiring significant computational resources.

Boiling regimes of a single droplet impinging on a superheated surface: Effect of the surrounding medium

Impinging droplets on a hot surface is a significant phenomenon in many industrial applications, such as spray cooling. Previous studies reported various morphological behaviours affecting the droplet's wetting, heat transfer, and evaporation characteristics. However, there is an ambiguity in understanding the influence of the surrounding medium on the resulting boiling regimes. The present work aims to study this aspect through an experimental investigation using high-speed photography and infrared thermography. During the experiments, the degassed FC-72 liquid droplets have impinged onto a heated chromium-plated calcium fluoride (CaF2) surface with a constant impact velocity. Three ambient conditions, such as saturated vapour (heated vapour), air at liquid saturation temperature (heated air), and air at room temperature (ambient air), are used. The surface temperature is varied in each ambience until the complete droplet dewetting, i.e., the Leidenfrost phenomenon has appeared. In this study, the stages of boiling are perceived as film evaporation, excessive and nominal bubbly boiling, transition, and Leidenfrost. With different surrounding media, the onset of a regime and its boiling morphology are distinct. During the film evaporation regime, the droplet heat transfer is high for the impact in ambient air, and the contact line evaporation is dominant in the vapour medium. In contrast, heat transfer is improved in a vapour medium during the bubbly boiling process, reaching up to 30% enhancement compared to the droplets in air surroundings. It is attributed to increased nucleation sites and excessive bubbling compared to air media. Correlations from the literature are also revisited to understand the onset of bubbly boiling and the droplet breakup at the Leidenfrost point. An overall comparison of droplet heat transfer during the boiling regimes in surrounding media is discussed in this paper.

Heat and Mass Transfer Processes and Evaporation of a Liquid Droplet on a Structured Surface

The characteristics of water droplet heating and evaporation on structured hydrophobic and hydrophilic surfaces in the range of static contact angles from 73° to 155° were studied experimentally using high-speed video recording. Two fundamentally different technologies for applying coatings on a metal surface were used in comparison with the results on a polished surface. Microscopic studies were conducted to identify the features of the formed coatings. The wetting properties were characterized by means of the static contact angle and the contact angle hysteresis: on polished surface No. 1 (contact angle—73°, hysteresis—11°), on structured surface No. 2 (contact angle—125°, hysteresis—9°), and on structured surface No 3 (contact angle—155°, hysteresis—7°). The experimental dependences of the droplet evaporation rate on the different surfaces under normal conditions (ambient air temperature—293 K, atmospheric pressure, humidity—35%) were obtained. The evaporation regimes of droplets on the surfaces under study were identified. Water droplets evaporated in the pinning mode on surfaces No. 1 and No. 2. When a water droplet evaporated on surface No 3, the droplet was in the constant contact angle regime for ≈90% of its lifetime. Based on the experimental data obtained, a two-dimensional model of conjugate heat and mass transfer was developed, which describes the heating and evaporation of a liquid droplet on structured hydrophobic and hydrophilic surfaces at a wide range of contact angles. Satisfactory agreement was obtained between the numerical simulation results and experimental data. Using the model, the fields of temperature, concentration and other key characteristics were established at different points in time. Recommendations for its application in the development of gas–vapor–droplet applications were formulated.

Experimental Study of Evaporation of Nanofluid Droplets on Substrates under Solar Radiation

This work is devoted to the experimental study of evaporating droplets of titania-, silica-, and diamond-based nanofluids on a substrate under solar radiation. The influence of various factors, including the type of a material, concentration of nanocomponents, irradiation direction, droplet volume, and substrate material, on the droplet evaporation has been investigated. As a result, the critical concentrations of nanoparticles, at which the evaporation rate reaches a stable level, have been determined for droplets of the studied nanofluids. The regimes and stages of the droplet evaporation process have been analyzed for the cases of the subcritical and critical nanoparticle concentrations. The efficiency of droplet evaporation under solar radiation has been shown to strongly depend on radiation direction. The effects of droplet volume and substrate material on the evaporation rate have been studied. In addition to the evaporation efficiency, the morphology of the structures deposited from the droplets has been analyzed. It has been shown that these structures depend on the concentration and material of nanoparticles, as well as on the regime of droplet evaporation. The results of this study enable one to gain a deeper insight into the behavior of the droplets during evaporation under irradiation especially in the IR region and confirm the promise of application of nanofluids in the solar thermal energy systems.

Dip-coating deposition of nanocomposite thin films based on water-soluble polymer and silica nanoparticles

Dip-coating deposition of nanocomposite thin films composed of polyvinylpyrrolidone and silica nanoparticles was studied using atomic force microscopy and scanning electron microscopy. The presence of particles (up to 5 wt%) did not modify the film thickness, which followed a classical additive law of an evaporative regime and a draining regime. Within film volume, no preferential retrieval of particles nor polymer occurred during deposition. This was consistent with the size of particles small enough so that particles were not trapped in the meniscus. For the thicker films prepared in pure capillary and draining regimes, the number of particles observed on the surface was independent of the thickness and was in full agreement with a homogenous distribution of the particles in the film. In contrast, for the thinner films (near the critical withdrawal speed) the number of particles differed in the two regimes. In the draining branch, the number followed the theoretical prediction with an increased number of particles as the thickness decreased, due to the presence of an exclusion zone at the interfaces. Unexpectedly, in the capillary branch, a depletion of particles was observed and could result from competition and interplay between time-dependent phenomena that took place during the dip-coating. This behavior will need to be carefully considered when preparing nanocomposite thin films where surface properties such as roughness or wettability need to be considered.