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Revealing the “structure–property” relationship is nontrivial for the application of materials. The magnetic configurations of FeGe are strongly dependent on the internal structures and positions of Fe and Ge atoms, e.g., B20-type cubic phase configuring into magnetic skyrmions. Although endotaxial FexGe islands on (001)Ge substrate can be obtained with a dynamically controlled growth process, it is not possible to obtain the crystal structural information from conventional approaches, such as X-ray diffraction or 2D electron diffractions due to the embedded growth structures at the nanometer scale, which are too small to be probed. Through a 3D rotational electron diffraction method combined with high resolution transmission electron microscopy, we have successfully determined the specific phase of each FexGe island on the Ge substrate. Three major phases (two hexagonal and one monoclinic) were found existing in the FexGe islands with nearly equal probability and independent of the deposition temperatures and time. All the islands with different phases were inclined to {111}Ge planes, which was due to a comparatively higher energy barrier for Fe atom diffusion through {111}Ge than other Ge planes. The epitaxial growth relationship at the interface was as follows: FeGemono(4−2−1)//Ge(111), FeGemono[15−6]//Ge[1−10], Fe3Ge2(201)//Ge(111) and Fe3Ge2[−112]//Ge[1−10], Fe13Ge8(40−1)//Ge(111) and Fe13Ge8[124]//Ge[1−10]. Ferromagnetism for the as-deposited samples was observed via SQUID, which most probably is attributed to the hexagonal FeGe phases. [ABSTRACT FROM AUTHOR]

ABSTRACT Molecular design, fabrication, and properties of thin-film coatings based on poly(2-methyl-2-oxazoline) (PMOX) and its copolymers were investigated to tackle problem of marine and bacterial fouling prevention. The ultraviolet crosslinkable macromonomer poly(2-methyl-2-oxazoline) dimethylacrylate was synthesized by cationic ring-opening polymerization in a microwave reactor initiated by 1,4-dibromobutane. In order to study the charge effect of the PMOX coatings on the adhesion of fouling organisms, PMOX surfaces with negative, neutral, and positive ζ-potential values were prepared by copolymerization with the positively charged monomer [2-(methacryloyloxy)-ethyl]trimethylammonium chloride. The coatings were stable in sea water for at least 1 month without significant reduction in the film thickness. The marine antifouling activity was evaluated against barnacle cyprids Amphibalanus amphitrite and algae Amphora coffeaeformis. Results showed that PMOX coatings provide effective reduction of the settlement regardless of the molar mass and surface charge of the polymer. Bacterial adhesion test showed that PMOX coatings effectively reduce Staphylococcus aureus and Escherichia coli adhesion. Owing to its good stability and antifouling activity PMOX has a great potential as antifouling coating for marine antifouling applications. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 275-283 [ABSTRACT FROM AUTHOR]

Sequential layer-by-layer (LbL) depositionof polyelectrolytesfollowed by chemical cross-linking was investigated as a method tofabricate functional amphiphilic surfaces for marine biofouling preventionapplications. A novel polyanion, grafted with amphiphilic perfluoroalkylpolyethylene glycol (fPEG) side chains, was synthesized and subsequentlyused to introduce amphiphilic character to the LbL film. The structureof the polyanion was confirmed by FTIR and NMR. Amphiphilicity ofthe film assembly was demonstrated by both water and hexadecane staticcontact angles. XPS studies of the cross-linked and annealed amphiphilicLbL films revealed the increased concentration of fPEG content atthe film interface. In antifouling assays, the amphiphilic LbL filmseffectively prevented the adhesion of the marine bacterium Pseudomonas(NCIMB 2021). [ABSTRACT FROM AUTHOR]

Realistic structures with complex features have been intricate challenges for structural health monitoring (SHM) with permanently installed transducers. Poor conformability of conventional rigid and brittle piezoceramic wafers is a typical issue of applications on surfaces with complex geometry. Moreover, the accompanied high-stress concentration requires high-sensitivity defect detection which is difficult to achieve with large-area monitoring methods like lamb waves at tens to hundreds kHz. Previously, in-situ conformally fabricated piezopolymer coating-based array transducers (PCATs) have been developed to build large-area, lightweight, flexible, and tunable Lamb wave networks. In this study, two novel local monitoring methods were investigated with PCATs, namely ultrasonic bulk wave array inspection and local ultrasonic resonance spectroscopy. For thick structures, ultrasonic bulk waves were generated and detected by PCATs with broadband operating frequencies (1–10 MHz) and flexible array parameters. Simulation tools and imaging algorithms of array inspection in non-destructive testing (NDT) were well implemented based on the analogous directivity pattern and normal-pressure coupling mechanism. As proof of concept, PCATs were applied on example structures with flat, concave, and convex surfaces for internal defect imaging. For thin-walled and/or multilayer structures, PCATs were used to measure local ultrasonic resonances, comparable to conventional non-contact methods. With negligible influence on local mechanical properties and broadband frequency response, multiple resonance peaks from 0 to 25 MHz were identified as zero group velocity (ZGV) Lamb modes and thickness vibration modes of host structures, which can be used as damage indices for local monitoring of corrosion, delamination, stiffness degradation, etc. Through embracing advanced NDT techniques with PCATs, high-sensitivity and quantitative local monitoring could be achieved with conformal networks, offering the possibility to integrate with large-area monitoring as multi-scale SHM for complex structures. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanocomposite photoacoustic transducer utilized to modulate ultrasonic surface wave for acoustic nonlinearity evaluation. • A structural optimization method of photoacoustic transducer for minimizing unwanted components of surface wave. • High-intensity narrowband surface wave with pure fundamental component acquired with optimized design non-ablatively. • Fully non-destructive microscale fatigue crack localization is achieved by nonlinear wave mixing using optimized designs. Laser ultrasonics is a promising non-contact inspection technique but faces challenges of low signal-to-noise and low amplitude under non-destructive thermoelastic regime. In this paper, a laser ultrasonic surface acoustic wave (SAW) modulation method and photoacoustic transducer (PAT) are proposed and combined with nonlinear wave mixing technique to inspect microscale fatigue crack. PATs comprised of candle soot nanoparticles and polydimethylsiloxane are systematically optimized and combined with a line-arrayed laser source to generate desired high-amplitude and pure fundamental SAWs. Two modulated SAWs with frequencies of 2.1 and 2.9 MHz are excited on a fatigued aluminum plate to generate nonlinear mixed components, and the ultrasonic responses over the fatigue crack regions are acquired with a scanning laser Doppler vibrometer. The localization of fatigue crack with microscale is eventually achieved by mapping the nonlinear parameter of the mixed components, which proves it a reliable and non-destructive technique to inspect the fatigue crack. [ABSTRACT FROM AUTHOR]

Silicone-based coatings are vulnerable to marine fouling organisms in static environments, which seriously hampers its practical application. Here, an amphiphilic acrylate polymer is designed by hydrophilic polyethylene glycol and antibacterial borneol, which is introduced into polydimethylsiloxane (PDMS) by covalent linking to prepare antifouling coatings. XPS and CA tests prove that amphiphilic acrylate polymer can migrate to coating surface in the marine environment to maximize antifouling properties. Mytilus edulis foot protein adhesion test find it can weaken interface force between Mefp-3 and surface. Laboratory antifouling performance evaluations confirm that the coatings are effective against the adhesion of bacteria (86.72 % reduction for E. coli), diatoms (87.76 % reduction for Nitzschia closterium). The good antifouling properties of coatings are ascribed to the synergistic effect among unique bicyclic monoterpene structure of natural non-toxic borneol and amphiphilic acrylate polymer on surface of coatings. Moreover, the coating is less harmful to the marine ecological balance than traditional coatings containing toxic biocides due to the introduction of natural non-toxic borneol. This work contributes new insights in the exploration of environmentally friendly coating with excellent static antifouling performance. • Dynamic migration of amphiphilic substances provide static antifouling capability. • The preparation process of the coating is simple. • Borneol presents environmentally friendly. [ABSTRACT FROM AUTHOR]

[Display omitted] • The transparent and amphiphilic silicone-based coatings are prepared conveniently. • Significantly lower protein adhesion force and reduced protein attachment are obtained. • Excellent fouling release performance is reached. • Significant differences in the expression of adhesion proteins in mussel adhesive plaque are verified. • The main reason is that the introduction of amphiphilic materials significantly reduces the adhesion strength at the coating-fouling interface. The amphiphilic antifouling coatings are effective for inhibiting fouling adhesion. Herein, the amphiphilic coatings were prepared by introducing polyether-modified polydimethylsiloxane (PE-PDMS). Uniform morphology, high transmittance, low surface roughness and amphiphilic property were obtained. PE-PDMS appearing as interspersed chains endowed the coating with amphiphilic characteristic. The artificial seawater promoted the migration of polyether to the surface. The protein adhesion force and quality were significantly reduced according to AFM-based colloidal probe technique and Quartz Crystal Microbalance with Dissipation, respectively. The coating exhibited antibacterial activity against Pseudoalteromonas xiamenensis (84.0%), Escherichia coli (69.2%) and Staphylococcus aureus (63.0%), respectively. 63.1% Halamphora. sp and 75.8% Nitzschia closterium f. had been inhibited, while the coatings possessed outstanding fouling release property with above 76.1% diatom detached after water exposure, proving that the amphiphilic parts weakened the adhesion of fouling. The mussel settlement assay confirmed that less adhesive plaques existed over the amphiphilic coatings. In addition, the expression for mussel adhesion proteins (mfp-5 and mfp-6) were significantly increased, demonstrating that amphiphilic polymers interfered with the adhesion response of the mussels. The effect on the interfacial behavior between fouling and coating is explored, providing a meaningful issue for the development of environmentally friendly antifouling coatings. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel Mo 2 C/Bi 2 WO 6 / indole derivative modified fluorinated acrylate polymer composite film is prepared. • The co-catalysts of Mo 2 C and fluoropolymer facilitate the charge separation. • It has excellent photothermal effect to enhance photocatalytic performance. • Multiple synergies contribute to superior antifouling properties. Micro-dynamic photocatalytic antifouling film based on the construction of heterojunction structure and built-in electric field to solve the insufficient antifouling efficiency of photocatalysis and polymers. Herein, a novel Z-scheme heterojunction hollow photocatalyst Mo 2 C/Bi 2 WO 6 (MB) was prepared and combined with indole derivative modified fluorinated acrylate to construct Mo 2 C/Bi 2 WO 6 /AFIP (MB/AFIP) micro-dynamic composite film. The MB/AFIP film exhibited excellent antifouling performance, and the inhibition ratios against Escherichia coli and Staphylococcus aureus reached 95.20% and 98.52%, respectively, and the anti-settling ratio against Halamphora sp. was 98.58%. The multi-enhanced antifouling performance is attributed to the built-in electric field assisted charge transfer between the Mo 2 C and Bi 2 WO 6 , and the increasing carrier separation via the fluorine component in the polymer. In addition, indole derivative grafted onto fluorinated acrylate polymer further enhanced the antifouling performance. The integration of the environmentally friendly antifouling resin AFIP, the internal hollow photothermal material Mo 2 C, and the typical photocatalyst Bi 2 WO 6 realized multiple synergistic mechanisms, which has potential application prospects in the field of marine antifouling. [ABSTRACT FROM AUTHOR]

A reliable non-destructive evaluation technique that accurately assesses the wall thickness and slag inclusions of ductile iron pipes prior to annealing is crucial to reducing costs in subsequent operations. The rough outer layer of the produced ductile iron pipes leads to considerable background noise, limiting the probability of detection of laser ultrasonic testing equipment. In this study, an improved variational mode decomposition approach based on particle swarm optimization is suggested initially to increase the signal-to-noise ratio. This technique develops a fitness function suitable for processing ultrasound signals. A scanning laser ultrasound technique is designed for simultaneous measuring wall thickness and finding slag inclusions in ductile iron pipes based on excitation locations and flight time. A finite element analysis simulation model is established to assess the feasibility of this scanning method. This experiment is conducted on a 4.2 mm thick sample with slag inclusion defects and a 6.2 mm thick sample without slag inclusion flaws. Experimental results demonstrate that the developed denoising technique may enhance the average signal-to-noise ratio from 34.83 dB to 43.15 dB; the accuracies of thicknesses measurement for two ductile iron pipes are 96.90% and 99.52%, respectively, and the slag inclusion defects can be recognized by ultrasonic amplitude or energy distribution in different B-scan images. It has potential implications for in-service inspection of ductile iron pipe structures. [ABSTRACT FROM AUTHOR]

[Display omitted] • A fully noncontact LU-based method is developed for fast and high-resolution visualization of defects. • A strategy adopted for fast defect localization using Rayleigh waves with circular scans. • High-resolution 3D imaging performed focusing around the located defect areas to quantify defects. • Various defect locations, depths, and sizes in AM parts are analyzed to verify the feasibility of the method. Additive manufacturing (AM) is an emerging technique for efficient fabrication of individually tailored and complex geometry parts. The fabrication process is prone to induce various defects that can have detrimental effects on the AM components. Therefore, a reliable technique that enables monitoring the integrity of AM components and in return helping to optimize the fabrication parameters in mission-critical structures is highly demanded. This work presents a fast and high-resolution damage visualization method using laser-ultrasonic (LU) imaging technique for accurately detecting and quantifying the subsurface defects in printed AM components. Specifically, a fully noncontact LU scanning system is implemented to generate and detect high signal-to-noise ratio laser ultrasonic waves using a pulsed laser and laser Doppler vibrometer, respectively. A strategy for fast defect localization using Rayleigh waves with circular scans is firstly proposed. The high-resolution 3D synthetic aperture focusing technique (SAFT) imaging with raster scans is subsequently performed focusing around the located damage areas to stereoscopically visualize and quantify the subsurface defects. The reconstructed images are further processed and improved using Gaussian filter algorithm to obtain accurate defect shapes, sizes, and positions. The feasibility of the proposed method is eventually verified on AlSi10Mg and stainless steel (316L) components containing subsurface defects with various types and dimensions. The measured sizes are well consistent with the designed values, suggesting that it is a reliable inspection method for AM parts to ensure quality control and feedback. [ABSTRACT FROM AUTHOR]

In-situ fabricated piezopolymer coating-based transducers have been developed to build large-area, lightweight and flexible networks for wave-based structural health monitoring (SHM). Meanwhile, their tunability can be realized by array electrodes for mode control with proper tuning methods. However, conventional standard tuning by phase matching seems not always effective. In this study, the excitation and acquisition mechanism of Piezopolymer Coating-based Array Transducers (PCATs) were first studied for Lamb waves. Distinctly different coupling mechanisms of PCAT actuators and sensors were discussed by analytical models and experimental verification, respectively. Then comprehensive parameter studies were performed to understand the filtering effect with finite temporal pulse duration of PCAT actuators, and finite spatial electrode span of PCAT actuators and sensors. Corresponding bias tuning methods were proposed with analytical solutions to improve mode control in Lamb-wave excitation and acquisition. This new guideline of designing array electrodes for PCAT actuators and sensors has been proven effective by successfully tuning the poor mode-controlled wavefield originated by the standard tuning method. Such tunability has great potential to be applied for detecting various damages in Lamb wave-based SHM, where sensitivity, accuracy, and signal interpretation can be improved with good control of particular frequency-mode selections. [ABSTRACT FROM AUTHOR]

Laser ultrasonic technique has been increasingly implemented for nondestructive testing and structural health monitoring. However, the poor signal-to-noise ratio (SNR) and low amplitude of laser generated ultrasonic signals under thermoelastic regime severely restrict its applications. In this paper, we propose a method for fabricating flexible, high-intensity and readily transplantable photoacoustic transducer (PAT) comprised of candle soot nanoparticles (CSNPs) and polydimethylsiloxane (PDMS), and utilize it to generate high SNR and amplitude ultrasonic signals for inspecting thick structures. A robotic-arm based layer-by-layer automatic scanning strategy is developed to realize candle soot nanoparticles (CSNPs) deposition with excellent homogeneity and thickness controllability, and the optimal thickness of PDMS/CSNPs nanocomposite layer to achieve high SNR and amplitude ultrasonic signal is obtained. In addition, a novel method for optimizing the PAT's structure to generate distinguishable and pure longitudinal ultrasonic signals is proposed, with amplitude over 100 times, and with center frequency (13.5 MHz) and −6 dB bandwidth (20.1 MHz) 29.8% and 35.8% higher than those generated without PAT. The optimized PAT is eventually combined with laser ultrasonic technique to successfully inspect and visualize the internal defects with various sizes (4, 2, 0.8 mm in diameter) of an aluminum component with thickness of 50 mm. With the merits of flexible and high-intensity nanocomposite PAT, the laser ultrasonics can be promisingly implemented for inspecting structure with large thickness and complex geometry under thermo-elastic mechanism. [Display omitted] [ABSTRACT FROM AUTHOR]

A reliable non-destructive testing technique that enables effective detection and quantification of defects within safety-critical curved structures is highly demanded both in manufacture and service. Conventional Ultrasonic Testing (UT) methods usually adopt planar ultrasonic probes and it is preferable to adjust the probe axis direction perpendicular to the curved surface, because both the transmitting and receiving sensitivities in the probe axis direction are the highest. This paper proposes a new UT method using a hemispherical-omnidirectional ultrasonic probe. This probe has an omnidirectional directivity pattern and can cover curved surfaces with normal incident ultrasounds at different scan positions without the necessity of adjusting the probe attitude and position to follow the curved surface profiles. A surface reconstruction algorithm is firstly proposed to estimate curved surface profiles, which is based on a fast-imaging algorithm for ultra-wideband radar called the Shape Estimation Algorithm based on the Boundary scattering transform and Extraction of Directly scattered waves (SEABED). This method only uses surface reflection echoes, and thus can inspect curved structures without knowing the surface profiles a prior. Further, the Synthetic Aperture Focusing Technique (SAFT) is implemented to generate a focused image of internal defects by performing delay-and-sum beamforming on defect echoes based on the reconstructed surface profile. The proposed UT method is eventually experimentally verified on a curved plexiglass specimen with 29.4 mm surface curvature radius containing three Ø 3.5 mm Side Drilled Holes (SDHs) at different depths. Results show that compared with the planar ultrasonic probe, the reconstructed surface profile via SEABED is much wider and accurate with a relative error ≤ 0.47%. All SDHs are not only clearly positioned with relative errors ≤ 7.43%, but also can be accurately quantified from the curvature radius of SDH indications in the SAFT images with relative errors ≤ 8.60%. This work proves that the UT method based on the hemispherical-omnidirectional ultrasonic probe can emerge as a promising technique to inspect curved structures with high efficiency and accuracy, which has great potential in practical applications. • A hemispherical-omnidirectional ultrasonic probe is presented for NDT purposes. • Curved structure is inspected by probe linear scanning with fixed attitude. • Surface profile is reconstructed from surface echo travel times with SEABED. • SAFT is used to generate a focused image with high accuracy. [ABSTRACT FROM AUTHOR]

Transmembrane protein 16 F (TMEM16F) is a Ca 2+ -activated homodimer which functions as an ion channel and a phospholipid scramblase. Despite the availability of several TMEM16F cryogenic electron microscopy (cryo-EM) structures, the mechanism of activation and substrate translocation remains controversial, possibly due to restrictions in the accessible protein conformational space. In this study, we use atomic force microscopy under physiological conditions to reveal a range of structurally and mechanically diverse TMEM16F assemblies, characterized by variable inter-subunit dimerization interfaces and protomer orientations, which have escaped prior cryo-EM studies. Furthermore, we find that Ca 2+ -induced activation is associated to stepwise changes in the pore region that affect the mechanical properties of transmembrane helices TM3, TM4 and TM6. Our direct observation of membrane remodelling in response to Ca 2+ binding along with additional electrophysiological analysis, relate this structural multiplicity of TMEM16F to lipid and ion permeation processes. These results thus demonstrate how conformational heterogeneity of TMEM16F directly contributes to its diverse physiological functions., (© 2024. The Author(s).)

This article reports the design, fabrication, and performance of an annular-array ultrasound transducer using (K, Na)NbO3 (KNN)-based lead-free 1-3 piezoelectric composite. The 1-3 piezoelectric composite based on lead-free 0.965(K0.45Na0.55)(Nb0.96Sb0.04)O3-0.035 Bi0.5Na0.5Zr0.85Hf0.15O3 (KNNS-BNZH) was first prepared with the dice-and-fill method. Different from previous reported studies, by patterning annular electrodes on this kind of 1-3 composite, a five-element annular-array transducer in diameter of 6 mm was designed and successfully fabricated and its working center frequency was increased from 5 MHz to around 15 MHz. Meanwhile, a -6 dB bandwidth of 50% was achieved for each annular-array element via a pulse-echo response measurement. Moreover, the obtained annular-array transducer exhibits low crosstalk (<-40 dB) and a high electromechanical coupling coefficient of around 0.7. The application of ultrasonic imaging was further demonstrated to show its excellent performance. Both theoretical analysis and experimental results show that the obtained annular-array transducer presented in this work has a competitive capability for ultrasonic application.

Background: Epilepsy (EP) is a common neurological disorder which is characterized by excessive abnormal synchronization of neuronal discharges in the brain due to chronic recurrent seizures of multiple etiologies. Variety of microRNAs have been associated with the occurrence and development of EP. This study aimed to determine the aberrant expression of miR-378 and miR-575 in EP patients to validate their potential to distinguish EP from healthy patients., Methods: RT-qPCR was used to determine the expressions of miR-378 and miR-575 from serum specimens of 106 EP and 103 control individuals. Clinical indicators between EP patients and controls were assessed. Based on surgical outcome, EP patients were further divided into Engel I-IV EP. The potentials of miR-378 and miR-575 in discriminating EP from healthy participants and predicting surgical prognosis were calculated by receiver operating characteristic (ROC) analysis., Results: We found the miR-378 and miR-575 were significantly declined (P<0.001) in Engel I-II and III-IV EP patients with no difference in clinical parameters compared. Moreover, miR-378 and miR-575 displayed high sensitivity, specificity, and accuracy in distinguishing EP patients and predicting surgical outcomes. Moreover, after surgical treatment, miR-378 and miR-575 levels were increased compared with those at admission, suggesting their potentials in treatment response., Conclusions: miR-378 and miR-575 could be utilized as novel and non-invasive serum biomarkers in discriminating EP from healthy controls and predicting surgical outcome, shedding new insights on epileptogenesis and EP treatment., Competing Interests: Conflict of Interest: The authors stated that they have no conflicts of interest regarding the publication of this article., (2022 Xiuxiu Li, Zhiqing Gao, Mei Ling Ma, Li Li, Shifeng Guo, published by CEON/CEES.)

The observation of regular ( h0 l) planar defects in α-MoO 3 crystals can be traced back to over 60 years ago. Two mechanisms have been proposed to interpret the formation of the planar defects. One is related to the diffusion of oxygen vacancies because of thermal-driven release of oxygen atoms in vacuum and the consequent crystallographic shear of α-MoO 3 . The other is associated with redox reactions of moisture and/or hydrocarbons that give rise to H x MoO 3 precipitates. Here, we report that regularly spaced (302) planar defects can be introduced into α-MoO 3 belt crystals by heating in liquid sulfur at 300 °C. These defects are undetectable by both atomic force microscopy and scanning electron microscopy at the crystal surface. Raman scattering enhancement and weakening have been observed for different phonon modes of α-MoO 3 at the (302) planar defects as probed from the (010) surface. Their comparisons with the Raman scattering enhancements at the edges and the argon-plasma-induced Raman spectral evolutions of the as-grown α-MoO 3 belt crystals provide new insights into the planar defects with regard to their formation and characteristics.

Giant circular blisters of up to 300 μm diameter and 10 μm deflection have been produced on nanometer-thick Al 2 O 3 -on-ZnO stacks grown by atomic layer deposition at 150 °C followed by annealing at elevated temperatures. Their shape changes upon varied ambient pressures provide evidence that their formation is related to an anneal-induced outgassing combined with their impermeability. The former mainly occurs in the bottom ZnO layer that recrystallizes and releases residual hydroxide ions at elevated temperatures while the latter is dominantly contributed by the pinhole-free Al 2 O 3 layer on top. Vibrations at a resonant frequency of ∼740 kHz are mechanically actuated and optically probed from an individual blister. By modulating the thickness and stacking sequence of Al 2 O 3 and ZnO, we further demonstrate a localized circular film swelling upon electron-beam irradiation and its recovery after reducing the irradiation flux. The elastic blistering and the recoverable swelling of the nanometer-thick films represent a miniaturized event-driven mechanical system for potential functioning applications.

We report on a molecular fabrication approach to precisely control surface ζ potentials of polymeric thin layers constructed by electrostatic layer-by-layer (LbL) assembly methods. The protocol established allows us to achieve surface isoelectric points (IEP) in the pH range of 6-10. Poly(acrylic acid) (PAA, a weak polyanion) and poly(diallyldimethylammonium chloride) (PDADMAC, a strong polycation) were chosen to build up the bulk films. The weak polycation polyethylenimine (PEI) was applied as a top layer. A unique feature of this approach is that the chemical composition of the top layer is not affected by the manipulation of the ζ potential of the films. Surface charge tuning is achieved by controlling the degree of ionization of the weak polyelectrolytes at various pH values and subsequent manipulation of the amount of polyelectrolyte deposited in the penultimate and last layers, respectively. Following assembly and characterization, the films were used as candidates for antifouling surfaces. The fouling behavior of barnacle cyprids and bacteria on the LbL films with similar hydrophilicity and roughness but different surface charge densities were studied. We found that more cyprids of Amphibalanus amphitrite settled on the negatively charged LbL film compared to the neutral or positively charged LbL film. In bacterial adhesion tests employing Pseudomonas, Escherichia coli, and Staphylococcus aureus, more bacteria were observed on the positively charged LbL film compared with the neutral and negatively charged LbL films, possibly as a result of the negative potential of the bacterial cell wall. The procedures proposed allow one to adjust surface isoelectric points of LbL architectures to achieve optimal antifouling performance of a given material taking into account specific pH values of the environment and the character of the fouler.