Enhancing mechanical properties of chitosan/PVA electrospun nanofibers: a comprehensive review

• Nur Areisman Mohd Salleh,
• Amalina Muhammad Afifi,
• Fathiah Mohamed Zuki and
• Hanna Sofia SalehHudin

Beilstein J. Nanotechnol. 2025, 16, 286–307, doi:10.3762/bjnano.16.22

• , and an increase in surface roughness, which reduced the water contact angle, without altering the bulk properties of the material. Similar observations of improved mechanical strength of plasma-treated chitosan/PVA/hydroxyapatite were reported using DBD plasma air, which is considered more cost

Bioinspired nanofilament coatings for scale reduction on steel

• Siad Dahir Ali,
• Mette Heidemann Rasmussen,
• Jacopo Catalano,
• Christian Husum Frederiksen and
• Tobias Weidner

Beilstein J. Nanotechnol. 2025, 16, 25–34, doi:10.3762/bjnano.16.3

• steel substrate and the elemental composition of the SNFs is difficult to disentangle. The contact angle of the uncoated surfaces was 71°. The contact angle of the SNF-coated surfaces is more difficult to measure as the droplet will not attach itself to the surface seen for Figure 3B and Figure 5D, in

• in Figure 4A shows no damage of ablation of the structure. This is also supported by the EDX analysis, which shows that the composition is not changed within the error margins as the amount of oxygen and silicone remains constant in Figure 4B. The water contact angle (Figure 4C) is reduced a bit from

• test. The water contact angle also remains unchanged after the decompression/explosion test (Figure 5D). Scale reduction on SNF-coated steel surfaces The scaling of SNF samples was tested in a flow loop designed for the observation of calcium carbonate scaling at surfaces. Coated and uncoated steel

A biomimetic approach towards a universal slippery liquid infused surface coating

• Ryan A. Faase,
• Madeleine H. Hummel,
• AnneMarie V. Hasbrook,
• Andrew P. Carpenter and
• Joe E. Baio

Beilstein J. Nanotechnol. 2024, 15, 1376–1389, doi:10.3762/bjnano.15.111

• to use. These biomimetic surface functionalization steps were confirmed by several complimentary surface analysis techniques. The wettability of each surface was probed with water contact angle measurements, while the chemical composition of the layer was determined by X-ray photoelectron

• copolymer (COC), silicon, and 316 stainless steel (SS) as our substrates. These substrates were first coated with PDA; then, a fluorinated thiol was attached to serve as the anchor for the infused fluid. The resulting surface modifications were then characterized by water contact angle measurements, atomic

• then sealed under nitrogen until ready to use. Immediately prior to use, the SLIPS formation was completed by adding a layer of liquid perfluorodecalin (PFD) to the surface (Figure 1). Water contact angle A custom setup was used similar to one previously described [31]. Static contact angle

Photocatalytic methane oxidation over a TiO₂/SiNWs p–n junction catalyst at room temperature

• Qui Thanh Hoai Ta,
• Luan Minh Nguyen,
• Ngoc Hoi Nguyen,
• Phan Khanh Thinh Nguyen and
• Dai Hai Nguyen

Beilstein J. Nanotechnol. 2024, 15, 1132–1141, doi:10.3762/bjnano.15.92

• surface interaction with gases during photocatalytic oxidative coupling can be analyzed using water contact angle analysis (as shown in Supporting Information File 1, Figure S2). The wettability of pure p-Si and the p-Si NW array are illustrated in Figure S3 (Supporting Information File 1). Pure p-Si had

• a water contact angle of 50.24°. Because of the nanowire array morphology, the p-Si NWs were more hydrophilic nature with a water contact angle of 3.36°, which manifests superior photocatalytic oxidative coupling. Raman spectra were conducted to confirm the surface composition of the synthesized

• spectrometer (DRS-UV, Shimazu UV-2450). The chemical structure of the catalyst surface was analyzed using a Raman spectrometer (excitation of 532 nm, ANDOR Monora 500i). The surface wettability of the thin film sample was measured using a static contact angle system (Biosin Scientific), as shown in Supporting

Modification of graphene oxide and its effect on properties of natural rubber/graphene oxide nanocomposites

• Nghiem Thi Thuong,
• Le Dinh Quang,
• Vu Quoc Cuong,
• Cao Hong Ha,
• Nguyen Ba Lam and
• Seiichi Kawahara

Beilstein J. Nanotechnol. 2024, 15, 168–179, doi:10.3762/bjnano.15.16

• characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, contact angle, thermal gravimetric analysis, and scanning electron microscopy. The XRD results showed the appearance of an amorphous region of silica particles at a diffraction angle of 22°. The formation of silica was

• conditions to determine the ideal condition to modify GO for grafting onto NR. The GO-VTES products were characterized using X-ray diffraction (XRD), contact angle, 29Si NMR, Fourier-transform infrared spectroscopy (FTIR), and morphology analysis. The GO-VTES was expected to improve the mechanical properties

• CP-MAS probe. The number of scans was 1000. Contact angles of the samples were measured by taking a photo of a drop of distilled water on the sample surface by a CCD camera. The determination of the contact angle was monitored by the SCA20 software using the Data-physic OCA20 system. Thermal

Berberine-loaded polylactic acid nanofiber scaffold as a drug delivery system: The relationship between chemical characteristics, drug-release behavior, and antibacterial efficiency

• Le Thi Le,
• Hue Thi Nguyen,
• Liem Thanh Nguyen,
• Huy Quang Tran and
• Thuy Thi Thu Nguyen

Beilstein J. Nanotechnol. 2024, 15, 71–82, doi:10.3762/bjnano.15.7

• resulted in prolonged drug release due to the delayed penetration of water into the polymer scaffolds. The change in the water contact angle of PLA nanofiber scaffolds loaded with BBR powder and BBR NPs is presented in Table 1. The PLA nanofiber scaffold possessed typical hydrophobic property with a water

• contact angle value of 130.1 ± 1.3°. This value was slightly decreased to 126.3 ± 1.6° when the BBR powder was added to the nanofibers. Meanwhile, the water contact angle value of the BBR NPs/PLA nanofiber scaffold was reduced by 23° relative to that of the PLA nanofiber scaffold, attributing to the

• polymer. The poor compatibility of hydrophilic BBR NPs and hydrophobic PLA resulted in a higher concentration of BBR located on the surface of nanofibers and lower water contact angle value of the scaffold compared to that of the scaffold prepared by the blend of hydrophobic BBR powder and hydrophobic PLA

Hierarchically patterned polyurethane microgrooves featuring nanopillars or nanoholes for neurite elongation and alignment

• Lester Uy Vinzons,
• Guo-Chung Dong and
• Shu-Ping Lin

Beilstein J. Nanotechnol. 2023, 14, 1157–1168, doi:10.3762/bjnano.14.96

• hydrophilic, O2 plasma-treated substrates [21]. We measured the water contact angle (CA) on the PU samples (Figure 1I) and found that all of the as-fabricated samples were hydrophobic (CA > 90°), with the nanostructured substrates being more so. Since the CA for flat PU indicates a hydrophobic surface, the

• ) Water contact angles on the PU films before and after O2 plasma treatment with the contact angle baseline in parallel with (I) or perpendicular to (J) the groove axis (***p < 0.001; n = 6). (K–M) 3D confocal fluorescence micrographs of immunostained adsorbed laminin on PU microgroove (K), pillar–groove

Conjugated photothermal materials and structure design for solar steam generation

• Chia-Yang Lin and
• Tsuyoshi Michinobu

Beilstein J. Nanotechnol. 2023, 14, 454–466, doi:10.3762/bjnano.14.36

• hydrophobic. The contact angle measurements revealed that the contact angles of the filter paper coated with DPP-H, DPP-DCV, and DPP-INCN were 123.9°, 113.4°, and 131.8°, respectively. In contrast, the contact angle of the bare filter paper remained at approx. 0°. These results suggest that coating the DPP

• observations (Figure 12a). These materials can stably float at the air–water interface (Figure 12b). The water contact angle of the bulk materials was as high as 130° without any surface modification (Figure 12c). Hydrophobic foams are considered to have advantages over hydrophilic foams, such as a greater

• of the foam floating at the air–water interface. (c) The water contact angle of the foam. (d–f) Time-dependent mass changes with and without the evaporator foam under different optical concentrations. Figure 12 was adapted from [34] (“A durable monolithic polymer foam for efficient solar steam

Dry under water: air retaining properties of large-scale elastomer foils covered with mushroom-shaped surface microstructures

• Matthias Mail,
• Stefan Walheim,
• Thomas Schimmel,
• Wilhelm Barthlott,
• Stanislav N. Gorb and
• Lars Heepe

Beilstein J. Nanotechnol. 2022, 13, 1370–1379, doi:10.3762/bjnano.13.113

• the surface tension of water, cos θ is the water contact angle of poly(vinylsiloxane) which was assumed to be 95°, and ρw = 997 kg/m3 the density of water, and g the gravitational acceleration. The reduced bubble lifetime for h > hmax whereas Vi is the initial volume of the air layer, with Ai the

Straight roads into nowhere – obvious and not-so-obvious biological models for ferrophobic surfaces

• Wilfried Konrad,
• Christoph Neinhuis and
• Anita Roth-Nebelsick

Beilstein J. Nanotechnol. 2022, 13, 1345–1360, doi:10.3762/bjnano.13.111

• (Figure 2) circular columns of constant diameter and constant contact angle, but proved impracticable for more realistic protrusion models showing eggbeaters with hydrophilic tips (implying non-constant column diameter and contact angle, see the project “Drag-reducing air–water interfaces” in appendix A

• ). Approximating the eggbeater-like protrusions, however, by circular columns of constant diameter and constant contact angle, Konrad et al. [38] and Apeltauer [39] arrived at an interesting result: If the columns are hexagonally arranged, an interface trapping an air layer exists for arbitrary values of (i) the

• contact angle, (ii) the diameters of the columns and (iii) the distances between the columns. In case they are quadratically arranged, however, certain contact angle/size combinations have to be excluded because the related interfaces cannot exist. This result illustrates how seemingly simple properties

Roll-to-roll fabrication of superhydrophobic pads covered with nanofur for the efficient clean-up of oil spills

• Patrick Weiser,
• Robin Kietz,
• Marc Schneider,
• Matthias Worgull and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2022, 13, 1228–1239, doi:10.3762/bjnano.13.102

• a significant increase of the contact angle of water droplets. The fractal structure minimizes contact area as well as adhesion forces between surface and water droplet, thereby equipping the surface with self-cleaning properties equivalent to the lotus effect [24]. Additionally, the high increase

• comparable high contact angle (95–100°, depending on the exact type [25][26][27]), which helps to achieve a high contact angle also for the structured surface. Second, we know from previous studies that it has a comparable wide process window for the hot pulling of nanofur [28]. Third, polypropylene is well

• on top of the nanofur are around the super hydrophobicity limit of 150° (see Figure 3b). This makes droplets easily roll off a sample even at minimal tilt (see the video in Supporting Information File 1). Contact angles were measured on a Dataphysics OCA 20 contact angle measurement machine using

Application of nanoarchitectonics in moist-electric generation

• Jia-Cheng Feng and
• Hong Xia

Beilstein J. Nanotechnol. 2022, 13, 1185–1200, doi:10.3762/bjnano.13.99

• interaction. The actual charge transfer is much more complicated, involving the contact angle, dielectric function, temperature, and ion concentration [15][16][17]. In MEGs, compared to bulk materials, nanoarchitectonics yields a higher specific surface area to the active material, which makes the contact

• induced voltage was detected from the top and lower electrodes during movement. Annealing treatment and plasma cleaning of the carbon particle layer have significant effects on the output voltage. After the treatment, the material changes from hydrophobic to hydrophilic, the contact angle decreases from

Electrocatalytic oxygen reduction activity of AgCoCu oxides on reduced graphene oxide in alkaline media

• Iyyappan Madakannu,
• Indrajit Patil,
• Bhalchandra Kakade and
• Kasibhatta Kumara Ramanatha Datta

Beilstein J. Nanotechnol. 2022, 13, 1020–1029, doi:10.3762/bjnano.13.89

• , materials, characterization data, electrochemical measurements, water contact angle measurements, and comparison of reported ORR activities of Ag-based catalysts. Acknowledgements Authors thank SRM IST for providing Microwave reactor facility and DST-FIST, Department of Chemistry [SR/FST/CST-66/2015(c

Interaction between honeybee mandibles and propolis

• Leonie Saccardi,
• Franz Brümmer,
• Jonas Schiebl,
• Oliver Schwarz,
• Alexander Kovalev and
• Stanislav Gorb

Beilstein J. Nanotechnol. 2022, 13, 958–974, doi:10.3762/bjnano.13.84

• samples were then fractured within the preparation chamber by cutting off a part of the mandible tip using a cold scalpel blade mounted on a user-controlled handle. Fractured samples were then sputter coated and examined in a frozen state as described above. Where possible, the contact angle of the

• channel between the ledge and central ridge (Figure 8B). In the flat area the layer measured 1.56 ± 1.04 µm in thickness (Figure 8C–F). Close to the unstructured sharp edge the layer was thin (0.053 ± 0.015 µm) (Figure 8G,H). In some places the contact angle of the surface layer on the cuticle could be

• mandibular epicuticle. From the cryo-SEM images similar to that in Figure 8H it is even possible to determine the contact angle of the fluid on the epicuticle. This substance has a relatively small contact angle (<30°) on the cuticle and is therefore likely to easily spread across the mandible surface. The

Design of a biomimetic, small-scale artificial leaf surface for the study of environmental interactions

• Miriam Anna Huth,
• Axel Huth,
• Lukas Schreiber and
• Kerstin Koch

Beilstein J. Nanotechnol. 2022, 13, 944–957, doi:10.3762/bjnano.13.83

• electron microscopy, gas chromatography–mass spectrometry, and by the determination of water contact angles, contact angle hysteresis, and tilting angles. Wheat leaves of different ages were covered exclusively with wax platelets. The extracted wheat wax was composed of alcohols, aldehydes, esters, and

• formation of biofilms [25][26]. A measure of the degree of wetting is the contact angle θ (CA). It describes the angle between the liquid–vapor interface and the liquid–solid interface. According to the CA, surfaces can be classified as superhydrophilic (0° < θ < 10°), hydrophilic (10° ≤ θ < 90

• , often so-called mixed wetting stages exist [35]. Contact angle hysteresis and tilting angle The wetting stages are closely related to the contact angle hysteresis (CAH) and the tilting angle (TA). Both quantities are therefore used to adequately describe the wettability of rough and heterogeneous

Bioselectivity of silk protein-based materials and their bio-inspired applications

• Hendrik Bargel,
• Vanessa T. Trossmann,
• Christoph Sommer and
• Thomas Scheibel

Beilstein J. Nanotechnol. 2022, 13, 902–921, doi:10.3762/bjnano.13.81

• cells but to even display antiviral attachment properties [58]. Superhydrophobic surfaces inspired by the Lotus-effect® (>150° contact angle) have been found to diminish bacterial adhesion due to reduced protein surface adsorption [59][60][61]. Superhydrophobicity relies on the combination of chemical

Engineered titania nanomaterials in advanced clinical applications

• Padmavati Sahare,
• Paulina Govea Alvarez,
• Juan Manual Sanchez Yanez,
• Gabriel Luna-Bárcenas,
• Samik Chakraborty,
• Sujay Paul and
• Miriam Estevez

Beilstein J. Nanotechnol. 2022, 13, 201–218, doi:10.3762/bjnano.13.15

• contact angle, which is reported to be favorable for biomedical applications. Likewise, Gatoo et al. proposed that amorphous titania materials are hydrophilic due to the presence of a higher concentration of hydroxy groups upon their surface and the high polarity of the O–Ti–O bond [23]. The surface

A comprehensive review on electrospun nanohybrid membranes for wastewater treatment

• Senuri Kumarage,
• Imalka Munaweera and
• Nilwala Kottegoda

Beilstein J. Nanotechnol. 2022, 13, 137–159, doi:10.3762/bjnano.13.10

• layer had a significant effect on the hydrophilicity of the membrane by decreasing the water contact angle from 130° to 13°. A water flux of 5.5 m3/m2/day, has been achieved by the membrane with the lowest contact angle [67]. Zhang et al. demonstrated the electrospinning of a blend of PLA and poly(3

• separating nanohybrid membrane with a SiO2 NP-integrated F-PBZ functional layer on the surface of an electrospun core–shell-structured membrane of CA/PI nanofibers. The membrane showed hydrophobicity with a water contact angle of 160° and superlipophilicity with an extremely low oil contact angle of 0°. The

• hydrophobic PVDF membrane to a hydrophilic membrane with a water contact angle of 22.72°. The nanohybrid membrane showed a dye removal efficiency of 88.9% and an adsorption capacity of 72.6 mg/g for IC [78]. Huong et al. developed a waste protein-immobilized cationic dye removal membrane from PAN. In this

A review on slip boundary conditions at the nanoscale: recent development and applications

• Ruifei Wang,
• Jin Chai,
• Bobo Luo,
• Xiong Liu,
• Jianting Zhang,
• Min Wu,
• Mingdan Wei and
• Zhuanyue Ma

Beilstein J. Nanotechnol. 2021, 12, 1237–1251, doi:10.3762/bjnano.12.91

• affect the boundary slip, and many previous investigations have shown that, from qualitative points of view, the positive slip length monotonically increases with the increase in the contact angle [57][58][59][60][61]. Furthermore, when studying the water flow on smooth surfaces, there is a

• quasiuniversal relationship between the slip length and the static contact angle as follows (see Equation 3 and Figure 2). It has been shown that Equation 3 can be interpreted on the grounds of definite physical principles, according to the microscopic connection between slip length, contact angle, and the

• liquid–solid interaction parameter [62]. However, it should be noted that this model is only applicable to cases of water slippage on smooth surfaces, and there are some deviations for water slippage on rough surfaces [66]. On the other hand, even on very smooth surfaces, the contact angle, surface–water

An overview of microneedle applications, materials, and fabrication methods

• Zahra Faraji Rad,
• Philip D. Prewett and
• Graham J. Davies

Beilstein J. Nanotechnol. 2021, 12, 1034–1046, doi:10.3762/bjnano.12.77

• parameters determining flow in a microchannel include blood viscosity, contact angle, hydrodynamic diameter, and driving forces such as surface tension. In addition, due to the elastic nature of the skin and its irregular surface, varying from person to person, and with age and position on the body, the

Nanoporous and nonporous conjugated donor–acceptor polymer semiconductors for photocatalytic hydrogen production

• Zhao-Qi Sheng,
• Yu-Qin Xing,
• Yan Chen,
• Guang Zhang,
• Shi-Yong Liu and
• Long Chen

Beilstein J. Nanotechnol. 2021, 12, 607–623, doi:10.3762/bjnano.12.50

• well as output electrons and build excellent electron-output “tentacles” and therefore increase the HER. Chen et al. [81] reported an ethynyl-bridged FSO–pyrene-based polymer (P66) (Figure 8) to further extend the conjugation. The water contact angle measurements showed that the wettability was

Spontaneous shape transition of Mn_xGe_1−x islands to long nanowires

• S. Javad Rezvani,
• Luc Favre,
• Gabriele Giuli,
• Yiming Wubulikasimu,
• Isabelle Berbezier,
• Augusto Marcelli,
• Luca Boarino and
• Nicola Pinto

Beilstein J. Nanotechnol. 2021, 12, 366–374, doi:10.3762/bjnano.12.30

• = α0, with: where e is the Neper number, ϕ = e−3/2cot(θ), with θ the contact angle of the island facet with the substrate. Γ = γecsc(θ) − γscot(θ) with γe and γs are the surface energy per unit area of the edge facet and the substrate, respectively. , where σb, ν and μ are the stress tensor in the

The nanomorphology of cell surfaces of adhered osteoblasts

• Christian Voelkner,
• Mirco Wendt,
• Regina Lange,
• Max Ulbrich,
• Martina Gruening,
• Susanne Staehlke,
• Barbara Nebe,
• Ingo Barke and
• Sylvia Speller

Beilstein J. Nanotechnol. 2021, 12, 242–256, doi:10.3762/bjnano.12.20

• (only 200 µm2). Therefore, we refrained from further utilizing PDMS substrates. Zeta potential and water contact angle were measured to be 8.6 mV and 68°, respectively, for PPAAm [62]. In case of the Au layer, −119 mV and 101°, respectively, were determined. Zeta potential measurements were performed

• software GraphPad Prism Version 6.05 (n = 3). Water contact angle values were obtained by the sessile drop method using the drop shape analyzer DSA25 (Krüss, Hamburg, Germany). Drop shape images of 1 µL water drops were acquired with the digital camera of the DSA25 under atmospheric conditions at room

• temperature (n = 3). Water contact angle values were calculated with the associated software (ADVANCE, V.1.7.2.1, Krüss, Hamburg, Germany) via Young's equation. Plasma polymer coating: The specimens were coated with a plasma-polymerized allylamine (PPAAm) nanolayer using a low-pressure plasma reactor (V55G

A 3D-polyphenylalanine network inside porous alumina: Synthesis and characterization of an inorganic–organic composite membrane

• Jonathan Stott and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2020, 11, 938–951, doi:10.3762/bjnano.11.78

• electron microscopy (SEM), near-infrared spectroscopy (NIR) and contact angle measurements (CA) reveals a change in morphology of the grafted polymer films, which is due to the rearrangement of the secondary structure of the polypeptides. No significant loss of the surface-grafted polypeptides was

• hydrolyzed monomers or an alternative polymerization mechanism [40][41]. The characterization of these composite materials was performed by NIR-spectroscopy (NIR), water contact angle measurements (CA), scanning electron microscopy (SEM) and thermogravimetric (TG) measurements. Mid- and near-infrared

• spectroscopic analysis provides qualitative information of the secondary structure of the grafted poly(amino acids). The measurement of the water contact angle allows conclusions regarding the hydrophobic or hydrophilic properties of the functionalized surface as well as the microstructure of the grafted

Preparation, characterization and photocatalytic performance of heterostructured CuO–ZnO-loaded composite nanofiber membranes

• Wei Fang,
• Liang Yu and
• Lan Xu

Beilstein J. Nanotechnol. 2020, 11, 631–650, doi:10.3762/bjnano.11.50

• , Netherlands). The mechanical properties of CNFMs were characterized using a universal electromechanical test machine Instron-3365 (Instron, Norwood, MA, USA). All samples were 4 cm × 1 cm rectangular membranes, and the measurement of each sample was repeated five times. Contact angle (CA) measurements of

• account the nanofiber diameters of the CNFMs presented in Table 1, it can be found that the pore sizes of the CNFMs are mainly determined by the nanofiber diameters. Larger nanofiber diameters lead to larger pore sizes. Wetting properties: The measured contact angle (CA) values of the CNFMs with different