Water Contact Angle Analysis Research Articles

Novel ultrafiltration membrane with MXene nanosheet/zinc oxide for water purification with high performance and enhanced antifouling properties

ABSTRACT Water scarcity is a pressing global issue, and developing sustainable methods for water treatment is crucial. Ultrafiltration membranes are essential for efficient water purification, but their development faces challenges such as flux performance and fouling. This study aims to address these challenges by incorporating MXene and zinc oxide (ZnO) into polymeric membranes. The synthesis of MXene was confirmed through X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Field Emission Scanning Electron Microscope (FE-SEM) analyses. The effects of ZnO@MXene content on membrane performance were evaluated through porosity calculations, FE-SEM, XRD, Energy Dispersive X-ray Spectroscopy (EDS), Atomic Force Microscope, and Water contact angle (WCA) analysis. The mechanical properties of the membrane were also assessed. The results show that the presence of nanoparticles significantly improved the water flux (433.7 L/m2.h), which was 3.9 times higher than that of the pristine membrane. Moreover, the antifouling properties of the membrane were enhanced with the addition of ZnO@MXene, resulting in a flux recovery rate of 97.6% and a BSA (bovine serum albumin) model fouling rejection of over 90%. This study contributes to the advancement of ultrafiltration membrane technology by demonstrating a novel approach to enhance membrane performance and antifouling properties.

The role of lignin as interfacial compatibilizer in designing lignocellulosic-polyester composite films

Advancing nanocomposites requires a deep understanding and careful design of nanoscale interfaces, as interfacial interactions and adhesion significantly influence the physical and mechanical properties of these materials. This study demonstrates the effectiveness of lignin nanoparticles (LNPs) as interfacial compatibilizer between hydrophilic cellulose nanofibrils (CNF) and a hydrophobic polyester, polycaprolactone (PCL). In this context, we conducted a detailed analysis of surface-to-bulk interactions in both wet and dry conditions using advanced techniques such as quartz crystal microbalance with dissipation (QCM-D), atomic force microscopy (AFM), water contact angle (WCA) measurements, broadband dielectric spectroscopy (BDS), and inverse gas chromatography (IGC).QCM-D was employed to quantify the adsorption behavior of LNPs on CNF and PCL surfaces, demonstrating LNPs’ capability to interact with both hydrophilic and hydrophobic phases, thereby enhancing composite material properties. LNPs showed extensive adsorption on a CNF model film (1186 ± 178 ng.cm−2) and a lower but still significant adsorption on a PCL model film (270 ± 64 ng.cm−2). In contrast, CNF adsorption on a PCL model film was the lowest, with a sensed mass of only 136 ± 35 ng.cm−2. These findings were further supported by comparing the morphology and wettability of the films before and after adsorption, using AFM and WCA analyses. Then, to gain insights into the molecular-level interactions and molecular mobility within the composite in dry state, BDS was employed. The BDS results showed that LNPs improved the dispersion of PCL within the CNF network. To further investigate the impact of LNPs on the composites’ interfacial properties, IGC was employed. This analysis showed that the composite films containing LNPs exhibited lower surface energy compared to those composed of only CNF and PCL. The presence of LNPs likely reduced the availability of surface hydroxyl groups, thus modifying the physicochemical properties of the interface. These changes were particularly evident in the heterogeneity of the surface energy profile, indicating that LNPs significantly altered the interfacial characteristics of the composite materials.Overall, these findings emphasize the necessity to control the interfaces between components for next-generation nanocomposite materials across diverse applications.

Application of hydrophobic catalyst in formaldehyde-ethylene condensation reaction.

Using hydrophobic aerogel (AGL) as the carrier, the catalyst supported p-toluene sulfonic acid (p-TSA) is synthesized, and the impact of the hydrophobicity of the catalyst on the formaldehyde-ethylene condensation reaction is investigated. Water contact angle, XRD, N2 adsorption/desorption, IR, and thermogravimetric analysis are used to characterize the catalyst. The outcomes demonstrate the ability of p-TSA to be loaded onto the carrier and the strong hydrophobicity of the catalyst when using AGL as the carrier. The elemental analysis results indicate that when AGL is employed as the carrier, the catalyst not only has more active sites than the SiO2-supported catalyst, but can also effectively limit the loss of active sites, reducing the loss rate from 25.82% to 15.03%. The findings demonstrate that 1,3-dioxane (1,3-DX) had a higher selectivity, rising from 16.2% to 33.3% when using AGL as the carrier. It is discovered that 1,3-propanediol (1,3-PDO) can be directly synthesized with a selectivity of up to 80.5% by employing acetic acid as a solvent in place of water.

First biological response on polyAcrylic Acid UV-grafted PDMS surface: Towards medical application

Several biomedical devices and implants are made with Poly(dimethyl siloxane) (PDMS) or include it. Its biocompatibility, transparency, thermal stability and low cost are some of the properties that made PDMS suitable for biomedical applications. However, some properties such as its hydrophobic character can lead to complications owing to bacteria adhesion for instance. For breast implant, which is implanted for a long-time, an enhanced surface integration can be needed to avoid bacterial biofilm formation and degeneration. In microfluidic systems or for catheters, the biofouling phenomena must be avoided. Surface covalent functionalization with bioactive polymers is an attractive strategy to fight these issues. This study deals with poly(acrylic) acid UV-grafting on PDMS surfaces. After chemical and mechanical characterizations, this work has focused on biological response occurring on the functionalized material. The results show slowdown fibroblasts proliferation. Investigation around protein (BSA, fibronectin, fibrinogen) adhesion, made possible to approach surface mechanism understanding. FTIR and water contact angle analysis highlighted the different protein affinity towards surface. These results provide clues about protein orientation on the surface, in order to adapt the surface functionalization to target a specific application.

Effects of graphene oxide and silane‐grafted graphene oxide on chitosan packaging nanocomposite films for bread preservation

AbstractThis study aims to investigate the dual effects of (3‐aminopropyl)triethoxysilane (APTES)‐grafted‐GO (A‐g‐GO), and titanium dioxide (TiO2) on the novel chitosan (CS) packaging nanocomposite films developed via the solution‐casting method. The chemical properties of GO and A‐g‐GO were assessed using FTIR and XRD. Subsequently, the chemical, structural, and physical attributes of all chitosan packaging nanocomposite films were analyzed through FTIR, XRD, TGA, DSC, AFM, water contact angle analysis, and food packaging tests. Successful silanization of GO by APTES was first confirmed. The highest surface roughness value was observed in the CS/A‐g‐GO/TiO2 film (16.574 nm) compared to pristine CS and other nanocomposite films. Incorporating GO into the CS matrix improved its thermal stability, suggesting robust bonding between GO and the polymer matrix. The addition of A‐g‐GO slightly decreased the contact angle value (107.7° for CS/A‐g‐GO), whereas TiO2 increased contact angles (117.3° for CS/GO/TiO2 and 119.4° for CS/A‐g‐GO/TiO2), suggesting a more hydrophilic structure with GO and A‐g‐GO and a more hydrophobic structure with TiO2. Bread samples showed no structural distortion over 40 days. Therefore, the dual impacts of A‐g‐GO and TiO2 on the pristine CS film imply that the resulting CS/A‐g‐GO/TiO2 film exhibits potential as an exceptionally efficient packaging material for prolonging the freshness of bread.

UV-crosslinked SBS block copolymers via thiol-ene reaction for efficient absorption and removal of oil/organic solvents from water

With the urgent need for oil/organic solvents spills disposal, the development of new sorbents with low cost, high sorption capacity, good selectivity and reusability is required. In the current work, three-dimensional structured absorbents have been rapidly fabricated by ultraviolet (UV)-crosslinking of styrene-block-butadiene-block-styrene (SBS) copolymers via thiol-ene reaction in 60 s, using poly-(mercaptopropyl)methylsiloxane (SMS) as crosslinker. The SBS-SMS absorbents were characterized by FT-IR, SEM, XRD, tensile strength, thermogravimetric, gel fraction and water contact angle analysis, which showed high tensile strength, good thermal stability, hydrophobicity, and acceptable gel content. The absorption capacity investigations were carried out in 7 types of organic liquids and 2 types of oils. The SBS-SMS0.005 exhibited the highest absorption performance in different organics, with the capacities of 74.6 g/g for dichloromethane, 20.1 g/g for kerosene, and 12.8 g/g for diesel oil, respectively. The impacts of sheet thickness on the absorption and desorption kinetics were studied, and the results showed that thinner absorbents illustrated faster absorption and desorption speed. Additionally, the SBS-SMS absorbents showed good selectivity and effectiveness in organic solvents/oil separation from water (separation efficiency > 93 %), well oil retention ability and oil desorption efficiency, floating properties, easy collection, as well as good reusability upon ten absorption-desorption cycles. The current SBS-SMS absorbents should have great potential in practical application for efficient oil/water separation as well as radioactive organic waste liquid treatment.

Economical and rapid mechanochemical synthesis of porous organic adsorbents with high hydrophilicity for ultra-fast removal of organic micro-pollutants from water

Various porous adsorbent materials have shown excellent adsorption performance for the removal of organic micro-pollutants in water. However, the practical application was hindered by the high cost or slow adsorption kinetics for most of porous adsorbents. Therefore, it is of great significance to develop economic adsorbent materials with characteristic like low-cost, easier preparation method, excellent adsorption kinetics etc.Herein, based on the Friedel-Crafts alkylation reaction, we reported three novel hydrophilic organic porous adsorbent frameworks (PAF-210, PAF-211 and PAF-212) with high Brunauer-Emmet-Teller (BET) surface area (956 ∼ 1384 m2/g) for phenolic micro-pollutants (bisphenol A (BPA), 2,4-dichlorophenol (2,4-DCP) and 2-naphthol (2-NO)) adsorption in water, which were prepared by using cheap trimethyl orthoformate (TMOF) as crosslinker and one-step simple ball milling synthetic method under room temperature within 15 min. Rich oxygen content promotes the resulting polymers to possess excellent hydrophilicity and wettability through water vapor adsorption and water contact angle analysis. The excellent hydrophilicity and proper porous properties made the resulting frameworks suitable as porous organic adsorbents to rapidly remove organic phenolic micro-pollutants from water. Among the resulting polymers, the PAF-210 exhibited ultra-fast adsorption (>94.0 % within 5 s), ultra-rapid adsorption kinetics with pseudo-second-order rate constants (K2, up to 7.72g/mg min−1 for 2,4-DCP), high pollutant adsorption capacity (up to 867.03 mg g−1 for BPA) and excellent recyclability (10 cycles with slight loss in adsorption capacity) through systematically characterization. The adsorption performances of PAF-210 are much better than these of the commercial activated carbons and β-cyclodextrin-based porous adsorbents (K2 = 1.50g/mg min−1 for P-CDP) etc. The favorable hydrophilicity, surface wettability, and adsorption performance of PAF-210 were significantly better than the comparative material constructed by using benzene and formaldehyde dimethyl acetal (FDA) through conventional thermal synthetic method, which is a very classic synthesis strategy in the field of porous materials. More importantly, the PAF-210 exhibited relatively superior adsorption performance on BPA, and it still presented excellent adsorption performance (removal efficiency ≥ 96.8 % within 5 s after 10 cycles) even at the safe range of BPA quantified in drinking water (BPA≤10 μg L−1, Standards for drinking water quality, GB5749-2022, China). XPS analysis and theoretical simulations proved that the excellent adsorption performance and ultra-fast adsorption rate stem from interactions including π-π interactions, hydrogen bonding and van der Waals interactions between PAF-210 and micro-pollutants.

Synthesis and characterization of stretchable isoprene-acrylic acid copolymer thin films

Copolymer thin films of isoprene with acrylic acid were synthesized using PECVD. In that way, the stretchable functionality of polyisoprene (PI) was combined with the hydrophilic functionality of poly(acrylic acid) (PAA) to obtain stretchable thin films with adjustable wettabilities. Deposition rates were found to change between 9 and 5.5 nm/min depending on the monomer flowrates. The analysis of water contact angle (WCA) values indicated that films having more AA units in their structures were more wettable. The stretchability of the films was assessed on laboratory gloves through stretch-release test and on PET sheet through bend-release test. No significant changes in the WCA values with no observable cracks and failures after successive tests were indication of stretchability of the copolymer films.

Meso-level surface modification of Hastelloy C276 by WS2 powder mixed electrical discharge alloying process through micro-EDM setup

The present research provides a rigid, wear-resistant lubricating localized layer on Hastelloy C276 (HC 276) surface at meso level by tungsten disulphide (WS2) powder suspended electrical discharge alloying (EDA) process through micro-electrical discharge machining (μ-EDM) setup. The performance characteristics of the coated surface were evaluated in terms of material deposition rate (MDR), surface morphology, surface roughness (Ra, Rz and Rq), recast layer thickness (RLT), compositional analysis, micro-hardness & indentation depth, wear test and water contact angle analysis. Maximum MDR has been achieved at 15 g/L WS2 concentration and 80 V of gap voltage whereas The RLT varies from 6.87 μm to 18.91 μm and is enhanced with the increase in WS2 concentration. The critical surface characterization confirms higher WS2 concentration reduces the crater dimensions and the presence of micro-cracks and micro-voids on the coated surface. The surface roughness has been increased with the gap voltage and capacitance, whereas higher WS2 concentration provides lower surface roughness. X-Ray diffraction analysis (XRD) confirms the presence of hard and wear resistance phases like WC, WO3, ZnO, and MoO2 on the coated surface. Energy-Dispersive X-Ray Spectroscopy (EDS) analysis along with elemental mapping justifies tool, dielectric materials, and powder particles migration on the coated surface. The micro-hardness of the coated surface (402 HV to 1166 HV) is enhanced by 3–4 times compared to the base material (299 HV) whereas the indentation depth has been reduced with the rise in WS2 concentration and lies within the RLT of the coated surface. The wear rate of the WS2 coated surface is drastically reduced compared to the base material with a lower value of coefficient of friction (COF). The coated surface became hydrophobic in nature with a contact angle of 109.6° compared to the hydrophilic base HC 276.

Maltodextrin-modified graphene oxide composite membrane applied to the enantioseparation of amino acids

The separation of enantiomers using chiral membranes has garnered much research interest. In this study, the enantioseparation of amino acids using chiral membranes, namely graphene oxide-ethylenediamine-maltodextrin (GO-EDA-MD) and GO-EDA-hydroxypropyl-MD (GO-EDA-HP-MD), was evaluated. HP-MD and MD were investigated as chiral selectors due to their inherent chirality. Various characterization techniques, including atomic force microscopy, Fourier transform infrared spectrometry, field emission scanning electron microscopy, water contact angle analysis, tensile properties, and thermal gravimetric analysis were employed to analyze the membrane structures. The evaluation of enantioseparation performance was conducted by employing tryptophan, phenylalanine, and tyrosine enantiomers. Optimal conditions for enantiomer separation were achived using a GO-EDA-HP-MD chiral composite (1.75 wt%), a feed concentration of 10 mg/L for each enantiomer, a separation time of 15 min, and a membrane effective surface area of 1.0 cm2. Also, the bovine serum albumin rejection was 90.0 %, and the water flux reached 37.1 L m−2 h−1. The highest enantiomeric excess (ee.%) values were 46.33 %, 76.97 %, and 73.04 % for tryptophan, phenylalanine, and tyrosine, respectively. The impact of voltage on ee.% and substance flux was also explored. This membrane was able to separate enantiomers successfully.

The anti-fouling and mechanism of Fe3O4@PVDF catalytic membrane in-situ coupling Fenton oxidation for organic pollutants removal

Polyvinylidene fluoride (PVDF) membrane is a promising technique for deep treatment of organic wastewater. However, the unavoidable membrane contamination greatly restrictions its field of application. Herein, we successfully prepared Fe3O4@PVDF membrane with excellent anti-fouling and catalytic ability by non-solvent induced phase inversion method. Meanwhile, Fe3O4@PVDF membrane was characterized by SEM, XRD, FTIR, Water contact Angle and membrane aperture analyzer. The properties of separation and anti-fouling were also evaluated by cross flow filtration of humic acid (HA). Compare with pristine membrane, the pure water flux, rejection rate and FRR respectively increase from 556.81 L m-2 h−1, 65.42 %, 68.26 % to 656.96 L m-2 h−1, 99.64 %, 90.17 % under in-situ Fenton reaction condition. In addition, further mechanistic insights by XDLVO theory, 3D-EEM and EPR verified that high anti-fouling mainly attribute to excellent hydrophilicity of Fe3O4@PVDF and in-situ degradation of HA by OH and 1O2· This work provides insights for improving the separation properties and anti-fouling properties of PVDF membrane in the field of treatment organic wastewater.

Improving membrane distillation performance by Fe(II) activated sodium percarbonate oxidation during the treatment of shale gas produced water

Membrane distillation (MD) offers promise for recycling shale gas produced water (SGPW), while membrane fouling is still a major obstacle in standalone MD. Herein, sodium percarbonate (SPC) oxidation was proposed as MD pretreatment, and the performance of the single MD, SPC-MD hybrid process and Fe(II)/SPC-MD hybrid process for SGPW treatment were systematically evaluated. Results showed that compared to raw SGPW, the application of SPC and Fe(II)/SPC led to the decrease of the fluorescent organics by 28.54 % and 54.52 %, respectively. The hydrophobic fraction decreased from 52.75 % in raw SGPW to 37.70 % and 27.20 % for SPC and Fe(II)/SPC, respectively, and the MD normalized flux increased from 0.19 in treating raw SGPW to 0.65 and 0.81, respectively. The superiority of SPC oxidation in reducing the deposited membrane foulants and restoring membrane properties was further confirmed through scanning electron microscopy observation, attenuated total reflection fourier transform infrared, water contact angle and surface tension analyses of fouled membranes. Correlation analysis revealed that hydrophobic/hydrophilic matters and fluorescent organics in SGPW took a crucial role in MD fouling. The mechanism of MD fouling mitigation by Fe(II)/SPC oxidation was attributed to the decrease in concentrations and hydrophobicity of organic by synergistic oxidation, coagulation and adsorption.

Deep eutectic solvent engineered GO/ZrO2 nanofiller for mixed matrix membranes: An efficient hydrogen gas separation

AbstractThis study explores fabrication and characterization of mixed matrix membranes (MMMs) for gas separation, employing a cost‐effective solution casting method. Polycarbonate (PC) and polystyrene (PS) blends are combined with graphene oxide (GO) and zirconium dioxide (ZrO2) nanofillers, with and without a deep eutectic solvent (DES) obtained through hydrogen bond exchange. Various MMMs compositions (2–20 wt%) are systematically examined using diverse characterization techniques, including differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, porosity determination, and water contact angle analysis. The MMMs exhibit enhanced gas permeability and selectivity, surpassing conventional membrane materials. Notably, H2 gas permeability reaches outstanding levels, with the composition PC/PS‐DES‐GO/ZrO2 at 20 wt% (PBC20‐IV) demonstrating the highest value of 86.32 Barrer. This superior performance is attributed to the unique properties of ZrO2, increased sorption capacity of GO, and enhanced thermal stability due to DES. Permeability data for CO2, N2, O2, and CH4 also show significant values, aligning with the observed trends in H2 permeability. Robeson's plot for the H2/CO2 gas pair surpasses the 2008 upper bound, placing the MMMs in a novel category for gas separation membranes. The incorporation of DES‐modified nanofiller blend composites presents a promising strategy for the potential production of pure hydrogen.

Bacterial nanocellulose-based nanopaper activated by β-cyclodextrin/ Salvia officinalis essential oil complexes for shelf life extension of shrimp

Active bacterial nanocellulose (BNC) nanopapers containing Salvia officinalis essential oil (SEO) in free form and encapsulated with β-cyclodextrin (βCD) were prepared, and their effect on the shelf life extension of shrimp was investigated. The GC–MS analysis of the SEO indicated the presence of various active compounds such as Thujone (21.53 %), Ledol (12.51 %) and Eucalyptol (11.28 %) in the essential oil composition. The cytotoxicity of the SEO and SEO-βCD complexes in the L929 cell line was quite low. FTIR analysis revealed new interactions in the nanopapers containing SEO-βCD complexes. Microscopic images showed that SEO-βCD complexation improved the surface morphology of the BNC nanopapers, whereas free SEO had a negative effect. X-ray diffraction patterns of the nanopapers showed higher crystallinity of the SEO-βCD containing nanopapers than that of the SEO-incorporated nanopapers. Moreover, the addition of the SEO-βCD complex improved the thermal properties of the BNC nanopaper. Water contact angle analysis showed higher hydrophobicity of the samples containing free SEO than that of the other samples. Both SEO-βCD and free SEO increased the elongation at break and decreased the tensile strength of the nanopaper. The prepared active films showed a greater antimicrobial effect on L. monocytogenes than on E. coli. The results showed a higher antioxidant capacity of the free SEO-containing nanopapers (58–78 %). The desirable effects of the active nanopapers on shrimp preservation were demonstrated by the results obtained for the microbial load, pH, and volatile nitrogen content of the product. The results demonstrate the potential of the prepared BNC active nanopapers for use in active antioxidant/antimicrobial food packaging.

Nanostructured ZnO thin film to enhance gutta-percha’s adhesion to endodontic sealers

BackgroundGutta-percha (GP) combined with an endodontic sealer is still the core material most widely used for tridimensional obturation. The sealer acts as a bonding agent between the GP and the root dentinal walls. However, one of the main drawbacks of GP core material is the lack of adhesiveness to the sealer. ZnO thin films have many remarkable features due to their considerable bond strength, good optical quality, and excellent piezoelectric, antibacterial, and antifungal properties, offering many potential applications in various fields. This study aimed to explore the influence of GP surface’s functionalization with a nanostructured ZnO thin film on its adhesiveness to endodontic sealers.MethodsConventional GP samples were divided randomly into three groups: (a) Untreated GP (control); (b) GP treated with argon plasma (PT); (c) Functionalized GP (PT followed by ZnO thin film deposition). GP’s surface functionalization encompassed a multi-step process. First, a low-pressure argon PT was applied to modify the GP surface, followed by a ZnO thin film deposition via magnetron sputtering. The surface morphology was assessed using SEM and water contact angle analysis. Further comprehensive testing included tensile bond strength assessment evaluating Endoresin and AH Plus Bioceramic sealers’ adhesion to GP. ANOVA procedures were used for data statistical analysis.ResultsThe ZnO thin film reproduced the underlying surface topography produced by PT. ZnO thin film deposition decreased the water contact angle compared to the control (p < 0.001). Endoresin showed a statistically higher mean bond strength value than AH Plus Bioceramic (p < 0.001). There was a statistically significant difference between the control and the ZnO-functionalized GP (p = 0.006), with the latter presenting the highest mean bond strength value.ConclusionsThe deposition of a nanostructured ZnO thin film on GP surface induced a shift towards hydrophilicity and an increased GP’s adhesion to Endoresin and AH Bioceramic sealers.

One-Step Formation of Pickering Double Emulsion Costabilized by Hydrophobic Silica Nanoparticles and Sodium Alginate.

Pickering double emulsions exhibit higher stability and biocompatibility compared with surfactant-stabilized double emulsions. However, tailored synthesis of particle stabilizers with appropriate wettability is time consuming and complicated and usually limits their large-scale adoption. Using binary stabilizers may be a simple and scalable strategy for Pickering double emulsion formation. Herein, commercially available hydrophobic silica nanoparticles (SNPs) and sodium alginate (SA) as binary stabilizers are used to prepare O/W/O Pickering double emulsions in one-step emulsification. The influence of system composition on double emulsion preparation is identified by optical microscopy, confocal laser scanning microscopy, and interfacial tension and water contact angle analyses. The formation of the O/W/O Pickering double emulsion depends critically on the aqueous phase viscosity and occurrence of emulsion inversion. Both hydrophobic SNPs and SA adsorb at the droplet surface to provide a steric barrier, while SA also reduces interfacial tension and increases aqueous phase viscosity, giving double emulsion long-term stability. Their microstructure and stability are controlled by adjusting the SA concentration, water-oil volume ratio, concentration and wettability of the particle stabilizer, and oil type. As a demonstration, the middle layer of the as-prepared O/W/O Pickering double emulsions can be cross-linked in situ with calcium ions to produce calcium alginate porous microspheres. We believe that our strategy for double emulsion formation holds great potential for practical applications in food, cosmetics, or pharmaceuticals.

Enhancing bioactivity and biocompatibility of polyetheretherketone (PEEK) for dental and maxillofacial implants: A novel sequential soaking process

Polyetheretherketone (PEEK) exhibits excellent biocompatibility, fatigue resistance, and an elastic modulus similar to bone, presenting broad application prospects in the field of dental and maxillofacial implants. However, the bioinertness of PEEK limits its applications. In this study, we developed a method to generate biocompatible and bioactive PEEK through a simple sequential soaking process, aimed at inducing bone differentiation and enhancing antibacterial properties. Initially, a three-dimensional (3D) porous network was introduced on the PEEK surface by soaking in concentrated sulfuric acid and water. Subsequently, the sulfonated PEEK surface was treated with oxygen plasma, followed by immersion in a dopamine solution to coat a polydopamine (PDA) layer. Finally, polydopamine phosphate ester-modified 3D porous PEEK was obtained through the reaction of phosphoryl chloride with surface phenolic hydroxyl groups. Systematic studies were conducted using scanning electron microscopy, X-ray photoelectron spectroscopy, water contact angle analysis, cell proliferation and adhesion, osteogenic gene expression detection, alkaline phosphatase staining, alizarin red staining, and bacterial culture. Overall, compared to unmodified PEEK, the modified PEEK significantly enhanced in vitro cell proliferation and adhesion, osteogenic differentiation, and antibacterial properties. The simple surface modification measures combined in this study may represent a promising technology and could facilitate the application of PEEK in dental and maxillofacial implants.

“Sandwich” Structure (PLA/Thymol Fibre Membranes/SAP/Paper Fibre) Antibacterial Pad for Preservation of Chilled Mutton

ABSTRACTThe antibacterial pad was developed to solve the preservation problem of chilled mutton. The antibacterial pad was a “Sandwich” structure (PLA/thymol fibre membranes/SAP/paper fibre), which could absorb water and inhibit bacteria. The fibre membranes are prepared by electrostatic spinning technology. The successful incorporation of thymol into the fibre membranes was proved by FTIR, SEM and water contact angle analysis. The release experiment showed that the fibre membranes (PLA/thymol) had a slow‐release effect, especially in fatty food simulants. According to the antibacterial experiment, the antibacterial pad had a significant inhibition effect on Escherichia coli and Staphylococcus aureus (the inhibition zone was 25 ~ 26 mm). In addition, the total viable count, total volatile alkaline nitrogen, pH value and drip loss showed that the antibacterial pads could effectively extend the shelf life of chilled mutton for 6 days. Therefore, the antibacterial pad has broad application prospects in meat preservation.

Orthotic Thermoplastic Demonstrates a Similar Contamination Potential with Bacillus Bacteria Recovered from Thermoplastic Radiation Therapy Patient Masks

Thermoplastics used to construct a variety of patient medical devices can become contaminated by harmful bacteria. We investigated whether two different Bacillus species recovered from patient radiation therapy thermoplastic masks could similarly contaminate thermoplastic material used to construct patient orthoses (splints). Bacillus bacteria form dormant spores, which have been shown to enhance its attachment to thermoplastics. Bacterial attachment and recovery were examined using an orthotic thermoplastic with an anti-stick coating being compared to uncoated material used in radiation therapy applications. Triplicate sample squares were seeded with a saline suspension of either B. cereus (MAB03F) or B. megaterium (DAB01F) containing a similar number of spores. Squares were subsequently sampled at 1 h, 1 week, 2 weeks, 4 weeks, and 8 weeks. The number of recovered bacteria was counted. Differences in material hydrophobicity were determined by water contact angle analysis. Both Bacillus species attached to each material within 1 h, and their spores were recovered at 8 weeks. However, a decreasing trend in adhesion, over time, was noted to the coated material with an opposite increasing trend in the uncoated material. Decreased Bacillus species spore adhesion to coated material with a lower hydrophobicity suggests a greater potential for spore transfer to patients wearing contaminated orthoses.

Valorisation of Agricultural Residue Bio-Mass Date Palm Fibre in Dry-Blended Polycaprolactone (PCL) Bio-Composites for Sustainable Packaging Applications

Abstract Purpose This study experimentally developed and characterised dry-blended Polycaprolactone (PCL)/date palm fibre biodegradable composites for sustainable packaging applications. Date palm fibres are collected from date palm trees as by-products or waste materials. They will be valorised in bio-composite application to promote fibre-based sustainable packaging items over their non-biodegradable synthetic polymer based conventional packaging products. In the dry-blending process, fibre and polymer are mixed with a shear mixer, while, in a melt-blending process, an extruder is used to extrude fibre/polymer blends after applying heating and high shear pressure to melt and mix polymer with fibres. Dry-blending process offers many comparative advantages, such as less equipment, steps, cost, process degradation, energy consumption and hence, lower harmful environmental emissions; while, a proper fibre/polymer mixing is a challenge and it needs to be achieved properly in this process. Therefore, it is important to understand the effects of dry-blending process on manufacturing of PCL/date palm fibre bio-composites for packaging applications, before promoting the dry-blending as a suitable alternative to the melt-blending process. Methods Short chopped fibres were grinded as powders and dry-blended at a ratio of (0 − 10%) (w/w) with PCL polymer using hand and a shear mixer for 30 min, following a compression moulding process to produce bio-composite samples. Tensile, water contact angle, SEM, TGA, DSC and DMA tests and analysis were conducted. The dry-blended PCL/date palm fibre composites’ properties were compared with reported melt-blended samples’ results found in literature. Results Dry-blended samples showed an increase in tensile modulus values (up-to 20%) with fibre inclusion and these values were found close to the melt-blended samples in the literature. Tensile strength and strain values were reduced which could be related to the poor fibre/polymer interface. Fibre addition affected the thermal, thermo-mechanical and crystallisation processes in PCL polymer matrix. Conclusion Dry-blending is capable of producing bio-composites with a very comparable properties to melt-blended counterparts, although a more details study is needed to conduct in future. The results of this study, could be used carefully to design dry-blended PCL/date palm fibre bio-composites for possible packaging applications. The irregular fibre distribution in dry-blended samples could be improved in different ways which should be investigated in future. Graphical Abstract