Effect Of Surface Topography Research Articles

A two-phase density-based solver for simulating wet steam flows with non-equilibrium condensation. II. Effects of 3D surface topography through nozzles

In Paper I, we developed a new two-phase flow solver and assessed its reliability and effectiveness through a series of numerical simulations. In Paper II, we utilized this solver to study the steam flow through nozzles characterized by three-dimensional surface topography. To generate random rough surfaces, we employed a multivariate Weierstrass–Mandelbrot function. Our numerical simulation results exhibited good agreement with the reported experimental data for pressure distribution. Moreover, we examined the changes in pressure, temperature, humidity, Mach number, average Nusselt number, and thrust as the wall surface morphology varied. We observed that the pressure field was prone to fluctuations, the boundary layer structure thickened and changed, the degree of condensation decreased with reduced humidity, three-dimensional Mach waves occurred, and the averaged Nusselt number decreased while thrust deviation increased. These findings contribute to a better understanding of the effects of fractal dimensions and condensation on random roughness in steam flow through nozzles and highlight the significance of incorporating surface topography into numerical simulations to improve accuracy and predictability in engineering applications.

Physicochemical cues are not potent regulators of human dermal fibroblast trans-differentiation

Due to their inherent plasticity, dermal fibroblasts hold great promise in regenerative medicine. Although biological signals have been well-established as potent regulators of dermal fibroblast function, it is still unclear whether physiochemical cues can induce dermal fibroblast trans-differentiation. Herein, we evaluated the combined effect of surface topography, substrate rigidity, collagen type I coating and macromolecular crowding in human dermal fibroblast cultures. Our data indicate that tissue culture plastic and collagen type I coating increased cell proliferation and metabolic activity. None of the assessed in vitro microenvironment modulators affected cell viability. Anisotropic surface topography induced bidirectional cell morphology, especially on more rigid (1,000 kPa and 130 kPa) substrates. Macromolecular crowding increased various collagen types, but not fibronectin, deposition. Macromolecular crowding induced globular extracellular matrix deposition, independently of the properties of the substrate. At day 14 (longest time point assessed), macromolecular crowding downregulated tenascin C (in 9 out of the 14 groups), aggrecan (in 13 out of the 14 groups), osteonectin (in 13 out of the 14 groups), and collagen type I (in all groups). Overall, our data suggest that physicochemical cues (such surface topography, substrate rigidity, collagen coating and macromolecular crowding) are not as potent as biological signals in inducing dermal fibroblast trans-differentiation.

Effects of grinding-induced surface topography on the material removal mechanism of silicon chemical mechanical polishing

Ultra-precision thinning technology using workpiece self-rotational grinding followed by chemical mechanical polishing (CMP) is extensively applied in the integrated circuit manufacturing process, which enables to obtain large size ultra-thin silicon wafers with high material removal rate and low damage layer thickness. However, an in-depth understanding of the influence caused by ground surface topography on material removal mechanism in silicon CMP process has not been revealed yet. This work systematically investigates the contact characteristics of the wafer-pad interface and corrosion behaviors of the ground silicon wafer immersed in polishing solution. Firstly, some silicon wafers are ground using different wheels and subsequently polished. The material removal depth during the whole CMP process is measured. Then, the intrinsic model of polishing pad is determined via mechanical property tests. A finite element method is adopted to evaluate the contact status, displacement distortion and stress distribution at the contact region between pad and ground wafer surface. Moreover, the chemical reaction mechanism between ground silicon wafer and polishing solution is revealed by utilizing X-ray photoelectron spectroscopy and electrochemical analysis. The influence of wafer surface topography on corrosion resistance in CMP process is illustrated. Finally, corresponding experimental results are explained from an atomic scale by a ReaxFF reactive molecular dynamics simulation model. This presented study demonstrates the corrosion promotion principle of ground silicon wafer in CMP process.

Effects of surface topography through laser texturing on the surface characteristics of zirconia-based dental materials: surface hydrophobicity, antibacterial behavior, and cellular response

The continuous need for high-performance implants that provide significant biological properties has led to extensive research into the topographic patterns of bioceramics in recent years. Their excellent aesthetics, biocompatibility, low plaque affinity, and ability to reproduce a natural-looking appearance have contributed to their success in dentistry. 3 mol% Yttria-stabilized zirconia (3YSZ) is gaining popularity as a material for dental implants due to its excellent mechanical properties and minimal degradation when exposed to body temperature. However, such materials show limited biological and antibacterial performance for dental applications. The purpose of this work was to develop microtopographies on the surface of 3YSZ ceramic by laser ablation technique, in order to improve its biological response and antibacterial behaviors. Two types of microtextures, including micro-grooves and micro-channels geometries were fabricated onto the zirconia ceramics using the laser ablation technique. The effects of different microtextures on the wettability, biological and antibacterial behaviors of 3YSZ ceramics were studied. The results indicate that all of the microstructure patterns are capable of improving the performance of 3YSZ. Wettability is a decisive factor that determines the antibacterial performance of textured zirconia ceramics. The microtextured surfaces all display hydrophobic behavior, thus yielding an effective improvement of antibacterial performance for 3YSZ ceramics. Cell-surface interactions were assessed for 7 days on both zirconia textured surfaces and a nontextured control with pre-osteoblast MC3T3-E1 cells. The obtained results showed the positive influence of textured zirconia surfaces on cell biological response.

Effect of Substrate Roughness and Contact Scale on the Tribological Performance of MoS2 Coatings

This present study aimed to clarify the effect of contact scale and surface topography of substrates with different roughnesses on the actual contact area, tangential stiffness, and tangential deformation of the substrate at micro- and macro-scales via finite element method (FEM) simulations, as well as the final tribological performances of MoS2 coatings by experiments. The MoS2 coatings were deposited on stainless steel (SS) substrates with different roughnesses, and the settings in the simulation models were based on the roughness of the SS substrates. The predicted tribological behavior of the simulation results was confirmed by the morphological and compositional analysis of the wear track using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), 3D profilometer, and Raman spectroscopy. The results showed that the substrate with a surface roughness of Ra 600 nm (R600), coated by MoS2 nanosheets, exhibited excellent tribological properties at both micro- and macro-scales. At the micro-scale, the lubrication lifetime of R600 was as long as 930 cycles, while the substrates with surface roughnesses of Ra 60 nm (R60) and Ra 6 nm (R6) had a lubrication lifetime of 290 cycles and 47 cycles, respectively. At the macro-scale, the lifetime of the substrate R600 was 9509 cycles, which was nearly six times longer than the 1616 cycles of substrate R60. For the rough surface of substrate, the surface grooves could not only effectively preserve the lubricant but also continuously release them, ensuring that the lubricants with low shear strength were always present in the contact interface. It was further verified that the high surface roughness of the substrate reduced friction and wear by reducing the actual contact area and enhancing the tangential stiffness of asperities, thereby prolonging the lubrication lifetime. The wear mechanisms were discussed in terms of the morphology and chemical composition of the wear tracks.

Effects of surface topography and specimen thickness on high-speed raindrop impact damage of CFRP laminates

Raindrop impact erosion has been observed since early days of aviation, and can be catastrophic for exposed materials during supersonic flight. A single impact waterjet apparatus is established for mimicking drop impacts at the velocities between 350 m/s and 620 m/s. Carbon Fiber Reinforced Polymer (CFRP) laminates with three different surface morphologies and specimen thicknesses are tested here. A central region with no visible damage has been noticed, surrounded by a “failure ring” with common damage patterns including resin removal, matrix cracking, fiber breakage and mass fiber loss. Asymmetric features are presented in the “failure ring” whose whole scope extends larger along the longitudinal direction than the transverse direction of the top layer. The mechanism of the resin removal is related to fiber–matrix debonding, and its onset and propagation can be facilitated by initial surface asperities with the shear action of the lateral jetting. In cases of multiple impact, good surface quality can slow down the evolution of resin removal and fiber exposure on the CFRP surface, reducing the erosion speed and delaying the occurrence of structural damages in the subsequent impacts. Rayleigh wave dominates the occurrence of matrix cracking on the CFRP surface, and subsequently, results in material loss and peeling of the top-layer because of lateral flow. With the increase of the specimen thickness, both the interlaminar and intralaminar failures decrease as the impact damage mechanism changes from plate bending stress to the reflection of stress waves.

Experimental study on the cytocompatibility of milling surface of poly-ether-ether-ketone (PEEK)

Poly-ether-ether-ketone (PEEK) is widely used in biomedical science because of its biocompatibility. However, the material is biologically inert. Many works have showed the potentiality of surface modification technique to enhance its biological performance, such as surface coating and impregnating bioactive materials into its substrate. Even so, these techniques are low efficiency or inapplicable in processing parts with complex structure. This thesis presents an experimental work of milling for the surface modification of PEEK, and its impact on the biological response is addressed. First, the influence of milling parameters on machined surface topography features is discussed based on the Taguchi method and end milling experiments. And then, the effect of the machined surface topography on the viability of fibroblasts is investigated by using cells from a mouse fibroblast L929 and the agar overlay test, MTT test. The experimental result indicated that there is a certain surface topography (characterized by Ssk = 0.011), which ensures the highest possible cells viability, but a significant decrease of L929 viability started with the surface roughness of Sa = 1.18 μm. The axial and radial depths of cut are the two most critical factors to affect surface topography parameters. It is concluded that the milling process significantly affects surface topography of PEEK, which in turn influences the L929 viability.

Surface roughness modulates EGFR signaling and stemness of triple-negative breast cancer cells.

Introduction: Cancer stem cells (CSC), a major culprit of drug-resistant phenotypes and tumor relapse, represent less than 2 % of the bulk of TNBC cells, making them difficult to isolate, study, and thus, limiting our understanding of the pathogenesis of the disease. Current methods for CSC enrichment, such as 3D spheroid culture, genetic modification, and stem cell conditioning, are time consuming, expensive, and unsuitable for high-throughput assays. One way to address these limitations is to use topographical stimuli to enhance CSC populations in planar culture. Physical cues in the breast tumor microenvironment can influence cell behavior through changes in the mechanical properties of the extracellular matrix (ECM). In this study, we used topographical cues on polystyrene films to investigate their effect on the proteome and stemness of standard TNBC cell lines. Methods: The topographical polystyrene-based array was generated using razor printing and polishing methods. Proteome data were analyzed and enriched bioprocesses were identified using R software. Stemness was assessed measuring CD44, CD24 and ALDH markers using flow cytometry, immunofluorescence, detection assays, and further validated with mammosphere assay. EGF/EGFR expression and activity was evaluated using enzyme-linked immunosorbent assay (ELISA), immunofluorescence and antibody membrane array. A dose-response assay was performed to further investigate the effect of surface topography on the sensitivity of cells to the EGFR inhibitor. Results: Surface roughness enriched the CSC population and modulated epidermal growth factor receptor (EGFR) signaling activity in TNBC cells. Enhanced proliferation of MDA-MB-468 cells in roughness correlated with upregulation of the epidermal growth factor (EGF) ligand, which in turn corresponded with a 3-fold increase in the expression of EGFR and a 42% increase in its phosphorylation compared to standard smooth culture surfaces. The results also demonstrated that phenotypic changes associated with topographical (roughness) stimuli significantly decreased the drug sensitivity to the EGFR inhibitor gefitinib. In addition, the proportion of CD44+/CD24-/ALDH+ was enhanced on surface roughness in both MDA-MB-231 and MDA-MB-468 cell lines. We also demonstrated that YAP/TAZ activation decreased in a roughness-dependent manner, confirming the mechanosensing effect of the topographies on the oncogenic activity of the cells. Discussion: Overall, this study demonstrates the potential of surface roughness as a culture strategy to influence oncogenic activity in TNBC cells and enrich CSC populations in planar cultures. Such a culture strategy may benefit high-throughput screening studies seeking to identify compounds with broader tumor efficacy.

Developmental Features, Influencing Factors, and Formation Mechanism of Underground Mining-Induced Ground Fissure Disasters in China: A Review.

Mining-induced ground fissures are one of the major geological disasters affecting coal mines. In recent years, many effective monitoring methods have been developed to explore the developmental characteristics and nature of mining-induced ground fissures for being treated scientifically. This paper is mainly on the development law and mechanism of mining ground fissure research results which have been comprehensively combed, highlighting the development trend, including the formation condition, development features, influencing factors, and mechanical mechanism of mining-induced ground fissures. Outstanding issues are discussed and future research hot spots and trends are pointed out. The major conclusions include: (1) under the shallow coal mining condition, because the rock layer fault zone directly reaches the surface, the ground fissure usually develops seriously; (2) mining-induced ground fissures are generally divided into four types: tensile fissures, compression fissures, collapsed fissures, and sliding fissures; (3) mining-induced ground fissures are affected by the coupling effect of underground mining and surface topography. The main factors are geological mining conditions, surface deformation, and surface topography, including rock and soil structure, rock and soil mechanical properties, surface horizontal deformation, surface slope, and so on; and (4) to ensure the safety of underground mining, temporary ground fissures formed during the process of coal mining must be treated when ground fissures and rock ground fissures are connected. The results of this article make up for the deficiencies of the relevant research, provide the basis and direction for future research, and have universal applicability and scientific guiding significance.

Nanofiber-based glaucoma drainage implant improves surgical outcomes by modulating fibroblast behavior.

Biomaterials are implanted in millions of individuals worldwide each year. Both naturally derived and synthetic biomaterials induce a foreign body reaction that often culminates in fibrotic encapsulation and reduced functional lifespan. In ophthalmology, glaucoma drainage implants (GDIs) are implanted in the eye to reduce intraocular pressure (IOP) in order to prevent glaucoma progression and vision loss. Despite recent efforts towards miniaturization and surface chemistry modification, clinically available GDIs are susceptible to high rates of fibrosis and surgical failure. Here, we describe the development of synthetic, nanofiber-based GDIs with partially degradable inner cores. We evaluated GDIs with nanofiber or smooth surfaces to investigate the effect of surface topography on implant performance. We observed in vitro that nanofiber surfaces supported fibroblast integration and quiescence, even in the presence of pro-fibrotic signals, compared to smooth surfaces. In rabbit eyes, GDIs with a nanofiber architecture were biocompatible, prevented hypotony, and provided a volumetric aqueous outflow comparable to commercially available GDIs, though with significantly reduced fibrotic encapsulation and expression of key fibrotic markers in the surrounding tissue. We propose that the physical cues provided by the surface of the nanofiber-based GDIs mimic healthy extracellular matrix structure, mitigating fibroblast activation and potentially extending functional GDI lifespan.

Surface nanotopography and cell shape modulate tumor cell susceptibility to NK cell cytotoxicity.

Natural killer (NK) cells are innate cytotoxic lymphocytes exerting cytotoxicity against virally infected cells and tumor cells. NK cell cytotoxicity is primarily determined by biochemical signals received from ligands expressed on target cell surfaces, but it is also possible that biophysical environments of tumor cells, such as nanoscale surface topography typically existing on extracellular matrixes (ECMs) or cell morphology determined by ECM spaces or cell density, regulate NK cell cytotoxicity. In this study, micro/nanofabrication technology was applied to examine this possibility. Tumor cells were plated on flat or nanogrooved surfaces, or micropatterned into circular or elliptical geometries, and the effects of surface topography and tumor cell morphology on NK cell cytotoxicity were investigated. NK cells exhibited significantly higher cytotoxicity against tumor cells on nanogrooved surfaces or tumor cells in elliptical patterns than tumor cells on flat surfaces or tumor cells in circular patterns, respectively. The amounts of stress fiber formation in tumor cells positively correlated with NK cell cytotoxicity, indicating that increased cellular tension of tumor cells, either mediated by nanogrooved surfaces or elongated morphologies, was a key factor regulating NK cell cytotoxicity. These results may provide insight into the design of NK cell-based cancer immunotherapy.

Effects of surface patterning and topography on the cellular functions of tissue engineered scaffolds with special reference to 3D bioprinting.

The extracellular matrix (ECM) of the tissue organ exhibits a topography from the nano to micrometer range, and the design of scaffolds has been inspired by the host environment. Modern bioprinting aims to replicate the host tissue environment to mimic the native physiological functions. A detailed discussion on the topographical features controlling cell attachment, proliferation, migration, differentiation, and the effect of geometrical design on the wettability and mechanical properties of the scaffold are presented in this review. Moreover, geometrical pattern-mediated stiffness and pore arrangement variations for guiding cell functions have also been discussed. This review also covers the application of designed patterns, gradients, or topographic modulation on 3D bioprinted structures in fabricating the anisotropic features. Finally, this review accounts for the tissue-specific requirements that can be adopted for topography-motivated enhancement of cellular functions during the fabrication process with a special thrust on bioprinting.

Fault strength and rupture process controlled by fault surface topography

Faults are rarely completely smooth, with topographic undulations coming from the distribution of asperities along the fault surface. Understanding the effects of fault surface topography on fault strength and earthquake source properties has been limited due to a lack of in situ observations in the field. Here we use simulated earthquake cycles on metre-scale laboratory faults to show the effects of the degree of fault topographic heterogeneity, especially on macroscopic peak strength represented by the shear force required to commence macroscopic failure. Our results demonstrate that the less heterogeneous fault is weaker, due to its lower macroscopic peak strength, and produces a larger stress drop on average than the more heterogeneous fault. Rupture along the less heterogeneous fault tends to propagate at subshear speed while the more heterogeneous fault accommodates a wider range of rupture speeds, including slow slip and supershear rupture. These results reveal how fault topographic heterogeneity affects macroscopic peak strength at rupture initiation and stress drop during rupture propagation, which has important implications for understanding natural faults and earthquakes. Simulated earthquakes on metre-scale laboratory faults reveal that fault surfaces with more heterogeneous topography are stronger, and rupture at a wider range of propagation speeds, than those that are less heterogeneous.

A peridynamic study on the effects of surface topography on rolling contact fatigue

A peridynamic(PD) fatigue simulation model is developed to study the effect of surface topography on rolling contact fatigue(RCF). Based on the PD fatigue damage-cumulative model proposed and verified in a previous study, a two-dimensional PD numerical model of the contact area of the rolling bearing is established, and the crack evolution and fatigue life of the model including surface topography with different dents and roughness are analyzed. The results show that cracks initiate from the shoulders of the dent, and then form spalling at the trailing edge, which is consistent with the experimental observations. Simulation of the model with sinusoidal and random rough profiles shows that there is competition between surface and subsurface crack nucleation. The larger the roughness amplitude or wavelength, the more prone to surface nucleation. Finally, the effects of roughness amplitude and wavelength on surface-originated pitting, subsurface-originated spalling and fatigue life are analyzed.

Effects of substrate topography on the regulation of human fibroblasts and capsule formation via modulating macrophage polarization

The host-material interface is critical in determining the successful integration of medical devices into human tissue. The surface topography can regulate the fibrous capsule formation around implants through macrophage polarization, but the exact mechanism remains unclear. In this study, four types of microgrooves (10 or 50 µm in groove depths and 50 or 200 µm in groove widths) were fabricated on polydimethylsiloxane (PDMS) using lithography. The microgroove surfaces were characterized using the laser scanning confocal microscopy and fourier transform infrared spectroscopy. The effect of surface topography on macrophage phenotypes and conditioned medium (CM) collected from macrophages on human foreskin fibroblast 1 (HFF-1) were investigated. The result revealed that a deeper and narrower microgroove structure means a rougher surface. Macrophages tended to adhere and aggregate on group 50–50 surface (groove depths and widths of 50 µm). THP-1 cell polarized toward both inflammatory M1 and anti-inflammatory M2 macrophages on the surface of each group. Meanwhile, CM from macrophages culture on PDMS differentially up-regulated the proliferation, migration and fibrosis of HFF-1. Among them, the group 50–50 had the strongest promoting effect. In vivo, the inflammatory response and fibrotic capsule around the implants were observed at 1 week and 4 weeks. As time passed, the inflammatory response decreased, while the capsule thickness continued to increase. The rough material surface was more inclined to develop a severe fibrotic encapsulation. In conclusion, this finding further suggested a potential immunomodulatory effect of macrophages in mediating the fibrotic response to implants and facilitated the design of biomaterial interfaces for improving tissue integration.

The effects of building position on surface and fatigue of DED-arc steel components

Recently, additive manufacturing (AM) of structural metallic components is analyzed regarding its potential use by industry and research. Next to the development of manufacturing processes, the mechanical properties are under investigation today. One of the quality measures of metallic components is the surface topography. DED-arc processes (direct energy deposition) result in relatively coarse surfaces, characterized by a distinct waviness with wave amplitudes in the mm-range. This is enhanced when applying horizontal building position in comparison to vertical position. Next to increased waviness, the load-bearing net cross sections are reduced as well. The surface topography determines the fatigue life properties of metallic components. While stress raising surface effects are generally well understood and fatigue (Structures 31: 576–589, 2021) of welded metals is established well, the fatigue behaviour of additively manufactured components is less investigated yet. In order to define surface quality levels for DED-arc components, the effects of surface topography on mechanical performance need to be understood. This article presents the manufacturing of high strength steel test coupons by the DED-arc process. The process parameters were varied with regard to the building position and different levels of surface quality were generated. The surfaces of different specimens were characterized and fatigue tests were conducted. The results were used to derive the surface influence on both, the effective load-bearing wall thickness and notch effects induced by the layer-by-layer building approach. A correlation between building position, surface waviness and fatigue strength was proven. In general, higher waviness resulted in reduced effective wall thickness and lowered fatigue strength. A difference in fatigue strength at 2 million load cycles of 20 to 30% was proven when printing in different building positions. The surface effect can be captured in the design concept when applying the effective notch stress approach with an averaging length of of ρ* = 0.4 mm. The fatigue strength is describable by a design S–N curve FAT160 and a k-value of 4.

Surface topography effect on tribological performance of water-lubricated journal bearing under mixed-EHL regime

Water-lubricated journal bearings (WLJB) are one of the important components of the stern tube shaft. Surface topography of WLJB is an important aspect in the design of stern tube shaft, and significantly affects the lubrication characteristics of WLJB. This work aims to investigate the effect of non-Gaussian surface topography on tribological performance of water-lubricated journal bearing (WLJB) under mixed-elastohydrodynamic lubrication (mixed-EHL) regime. The non-Gaussian flow factors, and a normalized Weibull probability density function is used to tackle the non-Gaussian roughness in hydrodynamic and asperity contact models respectively. From results, it is observed that skewness (S sk ) significantly affects both asperity contact pressure and hydrodynamic pressure along circumferential direction of bearing. It is concluded that for skewness, S sk = −1 to 1, lambda ratio falls between 1 to 3. The relation between altitude angle and skewness is established. The effect of bearing length to diameter (L/D) ratio on lubrication performance of WLJB is also discussed in detail.

Special Issue: Surface Topography Effects on the Functional Properties of PVD Coatings

The tribological contact between the moving components of each mechanical system degrades their performance and reliability due to friction and wear [...]

Tuning thermal transport across monolayer MoS2/Si heterostructure via substrate nanogrooving

Substrate-supported two-dimensional (2D) material heterostructures have been widely applied in electronic and photonic devices. However, the substrate reduces the original high thermal conductivity of 2D materials and limits the heat dissipation due to the interface thermal resistance. Here, the effects of the substrate surface topography on the thermal transport properties of the MoS2-Si heterostructure are investigated via molecular dynamics simulations. The decreased in-plane thermal conductivity of the monolayer MoS2 and surprisingly enhanced interface thermal transport of the MoS2-Si heterostructure are found by introducing the shallow nanogroove on the substrate surface. The results are ascribed to the morphology change of the supported MoS2, which bends to fit the substrate surface topography due to the van der Waals force at the small groove depth. In addition, the force weakens and the supported MoS2 restores to flat with the increase of groove depth, resulting in higher in-plane thermal conductivity and thermal resistance compared to those without grooves, which is due to the disappearance of the substrate effect in the nanogroove area. This work elucidates the fundamental understanding of heat transfer in heterostructures. It provides new insights to enhance the heat dissipation in electronic devices by introducing nanoscale roughness.

A study on the effect of surface topography of antifouling coatings on the settlement of fouling organisms

PurposeThe purpose of this paper is to study the correlation between different topographies and the reaction of Ulva Linza fouling species.Design/methodology/approachIn this research, topographies with a different method, such as hot embossing and hot pulling, were achieved, and biological analyses were done with macroalgae Ulva Linza cells. The effect of topography via local binding geometry (honeycomb size gradients) and Wenzel roughness on the settling of Ulva microorganisms was tested.FindingsAs a result, Ulva spores confirmed different reactions to a similar set of tapered microstructures that was in agreement with the results on distinct honeycombs. The local binding geometry and the Wenzel roughness factor “r” were dominant on settling of Ulva Linza spores.Research limitations/implicationsThe reaction of an organism at the interface of vehicles’ substrate is powerfully affected by surface topographies.Practical implicationsThe best embedment occurred on structures with bigger sizes than Ulva Linza’s spores. The density of settled spores was proportional to Wenzel roughness and the spores favour to attach to “kink sites” positions.Social implicationsUnfortunately, unpleasant aggregation of marine biofouling on marine vehicles’ surfaces, generate terrific difficulties in the relevant industry.Originality/valueThere was a sharp relationship between Wenzel roughness and settle of Ulva Linza spores. The local binding geometry and the Wenzel roughness factor “r” were dominant on settling of Ulva Linza spores.