Polyethylene Surface Research Articles

Antimicrobial and antibiofilm activity of silver nanoparticles against Salmonella Enteritidis.

Salmonella enterica serotype Enteritidis is one of the main pathogens associated with foodborne illnesses worldwide. Biofilm formation plays a significant role in the persistence of pathogens in food production environments. Owing to an increase in antimicrobial resistance, there is a growing need to identify alternative methods to control pathogenic microorganisms in poultry environments. Thus, this study aimed to synthesize silver nanoparticles (AgNPs) and evaluate their antibiofilm activity against poultry-origin Salmonella Enteritidis in comparison to a chemical disinfectant. AgNPs were synthesized, characterized, and tested for their minimum inhibitory concentration, minimum bactericidal concentration, and antibiofilm activity against S. Enteritidis strains on polyethylene surfaces. The synthesized AgNPs, dispersed in a liquid medium, were spherical in shape with a mean diameter of 6.2nm. AgNPs exhibited concentration-dependent bactericidal action. The bacterial reduction was significantly higher with AgNPs (3.91 log10 CFU [Formula: see text] cm-2) than that with sanitizer (2.57 log10 CFU∙cm-2). Regarding the time of contact, the bacterial count after a contact time of 30min was significantly lower than that after 10min. The AgNPs exhibited antimicrobial and antibiofilm activity for the removal of biofilms produced by S. Enteritidis, demonstrating its potential as an alternative antimicrobial agent. The bactericidal mechanisms of AgNPs are complex; hence, the risk of bacterial resistance is minimal, making nanoparticles a potential alternative for microbial control in the poultry chain.

Preparation, property determination and bridge health monitoring applications of self-sensing cement nanocomposites

Graphene has local superconductivity, very high electron mobility, good mechanical properties and high stability, and is therefore an excellent filler material for self-sensing cementitious composites. The incorporation of graphene provides a broad application prospect for the development of self-sensing cementitious composites. This work explored the effects of polyethylene (PE) fiber size and surface modifiers on the compressive and tensile properties of ultra-high performance concrete (UHPC). Then, graphene was added on this basis to observe the effect of graphene doping on the electrical properties of UHPC and to select the optimal doping amount. Finally, the mechanical properties and tensile and compressive self-sensing of the UHPC added with graphene were tested. Finally, the bridge with higher stress under self-weight is simulated by finite element to find the location of sensor placement and design a simple bridge health monitoring system.

HYDROPHOBICITY IMPROVEMENTS OF POLYMERS USED IN BIOMEDICAL APPLICATIONS.

Improvement in hydrophobicity is important for polymers used in various applications such as biomedical applications, as it can delay their degradation due to long-term exposure to moisture environments. Although a number of surface modification techniques have been developed over the years to improve hydrophobicity, their specific influences on hydrophobicity enhancement as well as long-term mechanical and tribological performances are yet to be fully understood. In this study, surface textures, with variation in type and geometry, are introduced on Ultrahigh Molecular Weight Polyethylene (UHMWPE) and High Density Polyethylene (HDPE) surfaces to study the effect of surface modification on hydrophobicity and long-term mechanical and tribological performances. Based on the theoretical study using Wenzel and Cassie-Baxter models, surface textures of various types and dimension are introduced on UHMWPE and HDPE surfaces. The results show that introduction of surface textures significantly improves the hydrophobicity of polymers. Specific relationship between texture type and geometry, and improvement in hydrophobicity is explored. Based on the comparison between experimental results and theoretical models, transition state modeling seems to be more suitable in describing the change in hydrophobicity with the addition of surface texture. The study provides useful guidelines to improve hydrophobicity of polymers for biomedical applications.

Usage of atmosphere pressure plasma for rapid polyethylene functionalisation exhibiting only minor ageing

The inert surface of polyethylene (PE) hinders its application in composites field. Here we report a rapid functionalisation method of molten PE using atmosphere pressure plasma with dry air as gas source to enhance its polarity. Treatment distance (between 10 mm and 30 mm) and treatment time (between 5 s and 20 s) are two key factors to impact the degree of functionalisation of PE. Various oxygen-containing groups, such as ketone groups (CO), ether groups (COC) and hydroxy groups (–OH), were introduced into molecules during plasma treatment. Furthermore, based on the higher relative CO content, PE in molten state was functionalised more rapidly than that in solid state. The static water contact angle dropped from 107 ° of once-molten PE to 84.5 ° of plasma treated PE at 20 mm for 20 s, which demonstrated the improved hydrophilicity of treated PE. Cross-linking structure preferred to be formed in plasma treated PE resulting in higher complex viscosity. The drop of crystallisation enthalpy and increase of half crystallisation time of plasma treated PE were due to cross-linking structure. The relative CO content in plasma treated PE remained constant even after 7 days showing only minor ageing effect. Plasma treatment is a rapid and economic method to improve polarity of PE in molten state, which provides a promising route to improve interfacial compatibility of PE-based composite.

Tetracycline accumulation in biofilms enhances the selection pressure on Escherichia coli for expression of antibiotic resistance

Microorganisms are present as either biofilm or planktonic species in natural and engineered environments. Little is known about the selection pressure emanating from exposure to sub-minimal inhibitory concentration of antibiotics on planktonic vs. biofilm bacteria. In this study, an E. coli bioreporter was used to develop biofilms on glass and high-density polyethylene (HDPE) surfaces, and compared with the corresponding planktonic bacteria in antibiotic resistance expression when exposed to a range of μg/L levels of tetracycline. The antibiotic resistance-associated fluorescence emissions from biofilm E. coli reached up to 1.6 times more than those from planktonic bacteria. The intensively developed biofilms on glass surfaces caused the embedded bacteria to experience higher selection pressure and express more antibiotic resistance than those on HDPE surfaces. The temporal pattern of fluorescence emissions from biofilm E. coli was consistent with the biofilm-developing processes during the experimental period. The increased expression of antibiotic resistance from biofilm bacteria could be attributed to the high affinity of tetracycline with extracellular polymeric substances (EPS). The enhanced accumulation of tetracycline in biofilms could exert higher selection pressure on the embedded bacteria. These results suggest that in many natural and engineered systems the higher antibiotic resistance in biofilm bacteria could be attributed partially to the retention antibiotics by the EPS in biofilms.

Transforming hydrophobicity of high-density polyethylene surface to hydrophilicity and superoleophobicity by surface grafted with polyvinyl alcohols for oil contaminants cleanup

High-density Polyethylene (HDPE) is widely used in industrial processes due to its excellent mechanical properties, solvent resistance and chemical stability. However, its surface usually shows high hydrophobicity and lipophilicity, which makes it ineffective in resisting contamination by oil pollution. In this study, Polyvinyl alcohols (PVA) were grafted onto the surface of the glycidyl methacrylate (GMA) grafted HDPE to improve the surface hydrophilization, furthermore, the surface structure of the PVA@GMA-HDPE and the factors affecting its hydrophilic modification were investigated. The introduction of the GMA in HDPE surface results in a large number of reactive sites on the inert surface of HDPE, which allows for further grafting of PVA onto the HDPE surface. Most importantly, the addition of PVA improves the water wettability, which reduced the water contact angle from 87.82° to 23.33° in the air and increased the oil contact angle from 107.30° to 156.90° under water. With the help of the significant improvements in resistance to oil contamination, the grease on the surface of the modified HDPE can be easily removed by washing with water after many repetitions. The low cost, simple manufacture and versatility of the PVA@GMA-HDPE with superior hydrophilicity and submerged superoleophobicity have significant application value for sewerage pipes and membranes.

The antibacterial potency and antibacterial mechanism of a commercially available surface-anchoring quaternary ammonium salt (SAQAS)-based biocide in vitro.

To determine the antimicrobial potency of a surface-anchored quaternary ammonium salt (SAQAS)-based biocide during in vitro wet and dry fomite assays and to determine the mechanism of killing bacteria on the surface. Wet and dry fomite assays were established in vitro for a commercially available biocide (SAQAS-A) applied to glass and low-density polyethylene (LDPE) surfaces. Both wet and dry fomite tests showed the active killing of Gram-positive and Gram-negative bacteria but not endospores. Assays measuring membrane permeability (ATP and DNA release), bacterial membrane potential and bacterial ROS production were correlated with the time-to-kill profiles to show SAQAS-A activity in suspension and applied to a surface. SAQAS-A is an effective biocide against model strains of vegetative bacteria. The killing mechanism for SAQAS-A observed minimal membrane depolarization, a surge in ROS production and assessment of membrane permeability supported the puncture of cells in both suspension and surface attachment, leading to cell death. SAQAS represents effective surface biocides against single challenges with bacteria through a mechanical killing ability that supports real-world application if their durability can be demonstrated to maintain residual activity.

Tunable β-crystals formation from transcrystallinity to cylindrites at PP/PE interface via using melt penetration engineering

Transcrytallinity plays a critical role in the interfacial crystalline morphology. However, it is rather rare to observe transcrytallinity grown from completely molten surface without using nucleating agent. Herein, we utilize melt penetration engineering to provide a sheared polymeric melt interface in order to tailor interfacial polypropylene (PP) crystalline morphology from β-transcrystals (β-TC) to β-cylindrites. The investigated system containing polymorphic PP as penetrating phase and polyethylene (PE) as penetrated layer were selected. Interestingly, we can clearly observe a continuous and ordered β-transcrystals (β-TC) at PP/PE interface and morphological transition from β-TC to β-cylindrites upon using higher molecular weight PE as the penetrated melt. Foreign PE surface plays an indispensable role in transcrystallinity formation since only α-spherulites were developed during identical PP penetrating PP process. The effects of surface-induced crystallization as well as coupling flow and temperature field have been discussed, in order to offer an insight on interfacial morphological transition. Consequently, melt penetration engineering can provide a facile and scalable route to achieve designed interfacial morphology from β-TC to β-cylindrites, which opens a new perspective to develop interfacial crystalline morphology. • Melt penetration to design interface. • Tunable structure from transcrystal to cylindrite. • β-interfacial morphology is developed.

Is Heterotopic Ossification Removal From Alloplastic Temporomandibular Joint Prosthesis Using Er,Cr:YSGG Laser Superior to Conventional Methods?

Heterotopic ossification (HO) formed over the major components and fixation screw heads of an alloplastic temporomandibular joint replacement (TMJR) prosthesis can result in decreased quality of life, limited function, prosthesis failure, and hinder prosthesis revision, replacement, or removal. This study simulated HO removal from the major components and fixation screw heads of alloplastic TMJR prostheses using an erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser and compared the results to conventional methods of HO removal. The surface morphology and chemical structure of the exposed components were analyzed. The investigators hypothesize that HO removal with an Er,Cr:YSGG laser causes less damage to TMJR prosthesis components compared to conventional HO removal methods. This multiple test descriptive analysis simulated HO removal from TMJR prostheses mounted to stereolithic models. Simulated HO removal was completed using a novel Er,Cr:YSGG laser method and conventional methods which utilized a fissure carbide bur in a high-speed rotary instrument, a standard osteotome, and an ultrasonic aspirator. Surfaces exposed on the TMJR prostheses were analyzed for morphological or chemical change using scanning electron microscopy, energy dispersive X-ray spectroscopy, and Raman spectroscopy. The Er,Cr:YSGG laser did not adversely affect the titanium screws or titanium components of the TMJR prostheses, while conventional methods of HO removal did. HO removal using the Er,Cr:YSGG laser and conventional methods both inflicted surface damage to the fossa ultrahigh molecular weight polyethylene component of the TMJR prostheses. Damage inflicted to titanium alloy or commercially pure titanium components of TMJR prostheses by conventional HO removal methods can be avoided by instead removing HO with an Er,Cr:YSGG laser. However, long exposure of the Er,Cr:YSGG laser to ultrahigh molecular weight polyethylene surfaces should be avoided. Additional research to expand on applications to other procedures and in other surgical fields is encouraged.

Effect of cationic, anionic and non-ionic surfactants on transport of microplastics: Role of adhesion of surfactants on the polyethylene surface

• Anionic, cationic, and nonionic surfactants all promote PE transport. • The greater adhesion of surfactants on the PE surface cause stronger PE transport. • Adhesion of surfactant on PE is related to the minimum single molecule adsorption area. In view of the amphiphilicity of surfactants, which can improve the hydrophilicity of polyethylene (PE) microplastics and increase the mobility of PE microplastics, the research on the transport behavior of PE microplastics under the coexistence of surfactants is still lacking and necessary. In this work, column experiments were carried out on the suspensions made of 15 surfactants mixed and dispersed with PE microplastics to explore the promoting effect of various surfactants on the transport of PE in saturated porous media. The dynamic contact angle of surfactant on PE surface and the surface tension and zeta potential of PE / surfactant dispersion system were measured. The interaction energy between PE / surfactant and medium, the adhesion of surfactant on PE surface were calculated respectively according to DLVO theory and Young's equation. The experimental results showed that different surfactants promoted the transportation of PE in the column to different degrees. The promotion degree of cationic, anionic and nonionic surfactants on PE transport from large to small were BG > PQ28 > CTAB > BLB > TLB, SDS > SLDED > DSS > SL > SDBS, POES > T40 > T80 > X100 > TX20, respectively. The recovery of PE in the column ranged from 17% to 99.93% under the surfactants. The calculation results of the adhesion of surfactant on PE surface also showed the same law. The minimum single molecule adsorption area (A sL ) of surfactant on PE surface was negatively correlated with the recovery of PE in the column under the same type of surfactant. The high adhesion of surfactant on PE surface was caused by the small adsorption area of single molecule, which finally made PE obtain higher stability and penetration. These findings provide new insights and methods for the fate and transport of microplastic and surfactant coexisting systems in soil and the prediction of their potential risk of groundwater pollution.

Characteristics and polyethylene biodegradation function of a novel cold-adapted bacterial laccase from Antarctic sea ice psychrophile Psychrobacter sp. NJ228

Biotreatment of polyethylene (PE) waste is an emerging topic in environmental remediation; in particular, the degrading enzymes requires further exploration. This study described a novel cold-adapted laccase (PsLAC) from an Antarctic psychrophile and characterized its PE-degradation ability. Homology modeling revealed that PsLAC possessed a typical bacterial laccase catalytic structure and unique cold adaptation structural characteristics such as few hydrogen bonds. Recombinant PsLAC (rPsLAC) retained 54.3% residual activity at 0 ℃ and presented increased Km values at low temperatures and a relatively high kcat value (42.65 s−1). Collectively, these factors help resist cold stress. rPsLAC possessed substantial salt tolerance at 1.5 M NaCl, with 119.80% activity, and Cu2+ enhanced its activity to 127.10%. PE-degradation experiments indicated that 13.2% weight was lost, and the water contact angle was decreased to 74.6°. Polar functional groups such as carbonyl and carboxyl groups on PE surface were detected in Fourier transform infrared spectroscopy; X-ray diffraction exhibited that crystallinity reduced by 25%. Enormous damage to PE surface and interior was observed via scanning electron microscopy. Overall, PsLAC, with its unique cold-adapted catalytic structure and biochemical characteristics, could supplement the diversity of sources and properties of bacterial laccases and ensure PE-degradation with a novel cold-adapted enzyme resource.

Change in adsorption behavior of aquatic humic substances on microplastic through biotic and abiotic aging processes

Interactions between microplastics (MPs) and humic substances (HS) are inevitable in MP-contaminated aquatic environment because of the ubiquitous presence of HS. In this study, we explored the effects of abiotic and biotic aging processes on the adsorption behavior of aquatic HS on MPs. Aging experiments were conducted using polyethylene (PE) as a representative MP, in which UV irradiation and microbial incubation were applied for 15 to 18 days to mimic the natural abiotic and biotic aging processes. Surface modifications after the aging treatments were evidenced by the appearance of CO, CO, O-C=O, and -OH groups; the formation of grooves on UV-aged PE; and the formation of biofilms on the surface of bio-aged PE. The specific surface areas of both treated PE MPs increased with aging. Higher HS adsorption on PE surface was observed after the aging treatments, with a highest kinetic rate for UV-aged PE than that for bio-aged PE. The adsorption isotherm models revealed that the aging processes enhanced the HS adsorption tendency, as evidenced by the highest adsorption capacity for UV-aged PE (~187 μg C/m2), followed by bio-aged PE (~157 μg C/m2) and pristine PE (~87.5 μg C/m2) for a comparable extended aging period (15–18 days). The difference was more pronounced at a lower pH. The enhanced HS adsorption was mainly attributed to the formation of hydrogen bonds, whereas HS adsorption on pristine PE was dominated by hydrophobic interactions and weak van der Waals interactions. Among the two identified fluorescent components (terrestrial humic-like C1 and protein-like C2), C1 exhibited a higher affinity for adsorption onto PE irrespective of aging. Our findings provide insights into the substantial changes that occur in the interactions between MPs and aquatic organic matter with aging processes, which may alter the fate and environmental impacts of MPs in many aquatic systems.

Preparation of Waterproof and Breathable Polyethylene (PE) Film Through One-Step Plasma Treatment

The waterproof and breathable multifunctional films have been widely used in advanced wear protection, medical treatment, monitoring, and the aerospace industry. In this research, we prepared a new class/kind of waterproof and breathable intelligent (WBI) films through plasma surface treatment, which can be applied in the health care field. After air plasma treatments, the structural properties of polyethylene (PE) film were observed by Scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), Thermogravimetry (TG), and Differential scanning calorimetry (DSC). It was found that plasma treatment etches PE fibers due to the sputter etching effect of plasma modification, leading to a crystallinity decrease. In addition, the changes in water contact angle, air permeability, and water vapor transmission rate of PE films were measured to illustrate their waterproof and breathable properties. After plasma treatment, the water contact angle of PE film reduced from 112.67∘ to 45∘, indicating the PE surface converted from hydrophobic into hydrophilic. The air permeability increased to 0.450[Formula: see text]mm/s and the water vapor transmission rate increased to 1419.788[Formula: see text]g/m[Formula: see text], which means the treated PE films are breathable but not permeable to liquid water. The improved performance in waterproof and breathability expands the application of PE film in the pharmaceutical field.

Processing and interpretation of core-electron XPS spectra of complex plasma-treated polyethylene-based surfaces using a theoretical peak model.

Interpretation of X-ray photoelectron spectroscopy (XPS) spectra of complex material surfaces, such as those obtained after surface plasma treatment of polymers, is confined by the available references. The limited understanding of the chemical surface composition may impact the ability to determine suitable coupling chemistries used for surface decoration or assess surface-related properties like biocompatibility. In this work, XPS is used to investigate the chemical composition of various ultra-high-molecular-weight polyethylene (UHMWPE) surfaces. UHMWPE doped with α-tocopherol or functionalised by active screen plasma nitriding (ASPN) was investigated as a model system. Subsequently, a more complex combined system obtained by ASPN treatment of α-tocopherol doped UHMWPE was investigated. Through ab initio orbital calculations and by employing Koopmans' theorem, the core-electron binding energies (CEBEs) were evaluated for a substantial number of possible chemical functionalities positioned on PE-based model structures. The calculated ΔCEBEs showed to be in reasonable agreement with experimental reference data. The calculated ΔCEBEs were used to develop a material-specific peak model suitable for the interpretation of merged high-resolution C 1s, N 1s and O 1s XPS spectra of PE-based materials. In contrast to conventional peak fitting, the presented approach allowed the distinction of functionality positioning (i.e. centred or end-chain) and evaluation of the long-range effects of the chemical functionalities on the PE carbon backbone. Altogether, a more detailed interpretation of the modified UHMWPE surfaces was achieved whilst reducing the need for manual input and personal bias introduced by the spectral analyst.

Effect of freeze-thaw cycle aging and high-temperature oxidation aging on the sorption of atrazine by microplastics

This study aims to better understand the aging characteristics of microplastics in the environment and the influence of aging microplastics on the migration and transformation of organic pollutants. In this study, polyvinyl chloride (PVC) and polyethylene (PE) were chosen as research objects, and the effects of two aging methods (freeze-thaw cycle aging and high-temperature oxidation aging) on their surface properties and atrazine (ATZ) sorption were investigated. The crystallinity of PE increased after freeze-thaw cycling and decreased after high-temperature oxidation. The freeze-thaw cycle destroys the amorphous region of PE, reducing the micropores on the PE surface and decreasing the ATZ adsorbed by PE. Although aging had no significant effect on the surface structure of PVC, it caused new oxygen-containing functional groups to be produced on the PVC surface, which reduced the ATZ adsorption capacity. These results show that the two aging modes change the surface properties of PVC and PE, thus affecting the sorption mechanism of ATZ, and provide a theoretical premise for the natural behavior and ecological chance assessment of ATZ in the presence of microplastics.

Piscirickettsia salmonis forms a biofilm on nylon surface using a CDC Biofilm Reactor.

Research into Piscirickettsia salmonis biofilms on materials commonly used in salmon farming is crucial for understanding its persistence and virulence. We used the CDC Biofilm Reactor to investigate P.salmonis (LF-89 and EM-90) biofilm formation on Nylon, Stainless steel (316L), Polycarbonate and High-Density Polyethylene (HDPE) surfaces. After 144h of biofilm visualization by scanning confocal laser microscopy under batch growth conditions, Nylon coupons generated the greatest biofilm formation and coverage compared to Stainless steel (316L), Polycarbonate and HDPE. Additionally, P.salmonis biofilm formation on Nylon was significantly greater (p≤.01) than Stainless steel (316L), Polycarbonate and HDPE at 288h. We used Nylon coupons to determine the kinetic parameters of the planktonic and biofilm phases of P.salmonis. The two strains had similar latencies in the planktonic phase; however, LF-89 maximum growth was 2.5 orders of magnitude higher (Log cell ml-1 ). Additionally, LF-89 had a specified growth rate (µmax) of 0.0177±0.006h-1 and a generation time of 39.2h. This study contributes to a deeper understanding of the biofilm formation by P.salmonis and elucidates the impact of the biofilm on aquaculture systems.

Effect of Humic Acids on Biofilm Formation on Polyethylene Surface and Its Biodegradation by Soil Bacteria

Effect of Humic Acids on Biofilm Formation on Polyethylene Surface and Its Biodegradation by Soil Bacteria

Antibacterial Activity of Rose Bengal Entrapped in Organically Modified Silica Matrices.

Photosensitizers (PSs) are known as powerful antibacterial agents that are activated by direct exposure to visible light. PSs can be noncovalently entrapped into the silica gel network for their controlled release into a contaminated area. The immobilization of PS-containing gel matrices on a polymer support expands their possible applications, such as antibacterial surfaces and coatings, which can be used for the disinfection of liquids. In the current study, we report the use of Rose Bengal (RB) incorporated into organically modified silica matrices (RB@ORMOSIL matrices) by the sol-gel technique. The RB matrices exhibit high activity against Gram-positive and Gram-negative bacteria under illumination by white light. The amount and timing of solidifier addition to the matrix affected the interaction of the latter with the RB, which in turn could affect the antibacterial activity of RB. The most active specimen against both Gram-positive and Gram-negative bacterial cells was the RB6@ORMOSIL matrix immobilized on a linear low-density polyethylene surface, which was prepared by an easy, cost-effective, and simple thermal adhesion method. This specimen, RB6@OR@LLDPE, showed the low release of RB in an aqueous environment, and exhibited high long-term antibacterial activity in at least 14 rounds of recycled use against S. aureus and in 11 rounds against E. coli.

Biomechanical effects of fixed-bearing femoral prostheses with different coronal positions in medial unicompartmental knee arthroplasty

BackgroundTo study the biomechanical effects of femoral prostheses at different coronal positions using finite element analysis and provide a clinical reference for unicompartmental knee arthroplasty (UKA).MethodsA normal knee joint model was established and verified, establishing 13 working conditions for the femoral prosthesis: the standard position, varus and valgus angles of 3°, 6° and 9° and medial and lateral translations of 1 mm, 3 mm and 5 mm. The stress changes at different positions were analysed, including the polyethylene (PE) insert upper surface, the surface of lateral compartment cartilage and the surface of cancellous bone under tibial prosthesis.ResultsThe stresses on the PE insert upper surface and the cancellous bone surface increased with increasing femoral prosthesis valgus/varus, and the stress increased gradually during medial to lateral translation. The stress change is more significant during valgus and lateral translation. However, the stress on the cartilage surface decreases in the process of varus to valgus and medial translation to lateral translation.ConclusionThe fixed-bearing femoral prosthesis of the medial UKA should avoid translation or varus/valgus tilt on the coronal plane as much as possible. The obvious misalignment of the femoral prosthesis will significantly affect the stress on the internal structure of the knee joint, especially the PE insert and cartilage surface. A femoral prosthesis coronal tilt of more than 6° may significantly increase the stress on the PE surface, and varus of more than 6° may significantly increase the stress on the cartilage surface. For the femoral prosthesis position at the distal end of the femoral condyle, it is recommended to be placed in the centre.

An effective method to optimise plasma immersion ion implantation: Sensitivity analysis and design based on low‐density polyethylene

AbstractThe performance of polymer surface treatment using plasma immersion ion implantation (PIII) depends on many operating parameters, such as treatment duration, radiofrequency power, pulsed bias voltage and pulse repetition rate, and the ion fluence applied on the polymer surface. Currently, the identification of optimal operating parameters to achieve specific performance targets is heavily based on trail and error with extensive experimental testing. Herein, we present an optimisation method based on sensitivity analysis using polynomial chaos expansion and experimental design with Kriging surrogate model to greatly reduce the amount of experiments. The combined effects of PIII operating parameters on low‐density polyethylene surface modifications are investigated, demonstrating the validation and effectiveness of the method and design. The new approach offers highly accurate and computationally efficient way for achieving optimum radical density, wettability and optical transmittance that are important for biomedical applications.