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  • 1.
    Cabezas, Ana Lopez
    et al.
    iPack VINN Excellence Center, School of Information and Communication Technology, KTH, Stockholm.
    Liu, Xianjie
    Dept of Physics, Chemistry and Biology, Linköping universitet.
    Chen, Qiang
    iPack VINN Excellence Center, School of Information and Communication Technology, KTH, Stockholm.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zheng, Li-Rong
    iPack VINN Excellence Center, School of Information and Communication Technology, KTH, Stockholm.
    Zhang, Zhi-Bin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Influence of Carbon Nanotubes on Thermal Stability of Water-Dispersible Nanofibrillar Polyaniline/Nanotube Composite2012In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 5, no 2, p. 327-335Article in journal (Refereed)
    Abstract [en]

    Significant influence on the thermal stability of polyaniline (PANI) in the presence of multi-walled carbon nanotubes (MWCNTs) is reported. By means of in-situ rapid mixing approach, water-dispersible nanofibrillar PANI and composites, consisting of MWCNTs uniformly coated with PANI in the state of emeraldine salt, with a well-defined core-shell heterogeneous structure, were prepared. The de-protonation process in PANI occurs at a lower temperature under the presence of MWCNTs on the polyaniline composite upon thermal treatment. However, it is found that the presence of MWCNTs significantly enhances the thermal stability of PANI's backbone upon exposure to laser irradiation, which can be ascribed to the core-shell heterogeneous structure of the composite of MWCNTs and PANI, and the high thermal conductivity of MWCNTs.

  • 2.
    de Amorim Lima, Nayane Maria
    et al.
    Fed Univ Ceara UFC, Organ & Inorgan Chem Dept, Lab Prod & Proc Technol LPT, Campus Pici, BR-60440900 Fortaleza, Ceara, Brazil.
    Camargo Avila, Harold Jose
    Pontifical Catholic Univ Rio de Janeiro PUC Rio, Dept Phys, Mol Optoelect Lab LOEM, BR-22451900 Rio De Janeiro, RJ, Brazil;Univ Atlantic, Dept Phys, Puerto Colombia, Atlantico, Colombia.
    Marchiori, Cleber
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Sampaio, Samuel Gondim
    Fed Univ Ceara UFC, Organ & Inorgan Chem Dept, Lab Prod & Proc Technol LPT, Campus Pici, BR-60440900 Fortaleza, Ceara, Brazil.
    Ferreira Mota, Joao Paulo
    Fed Univ Ceara UFC, Organ & Inorgan Chem Dept, Lab Prod & Proc Technol LPT, Campus Pici, BR-60440900 Fortaleza, Ceara, Brazil.
    Pereira Ribeiro, Viviane Gomes
    Univ Int Integrat Afro Brazilian Lusophony, Inst Exact & Nat Sci ICEN, BR-62790000 Redencao, CE, Brazil.
    Clemente, Claudenilson da Silva
    Fed Univ Ceara UFC, Organ & Inorgan Chem Dept, Lab Prod & Proc Technol LPT, Campus Pici, BR-60440900 Fortaleza, Ceara, Brazil.
    Mele, Giuseppe
    Univ Salento, Dept Innovat Engn, Via Arnesano, I-73100 Lecce, Italy.
    Cremona, Marco
    Pontifical Catholic Univ Rio de Janeiro PUC Rio, Dept Phys, Mol Optoelect Lab LOEM, BR-22451900 Rio De Janeiro, RJ, Brazil.
    Mazzetto, Selma Elaine
    Fed Univ Ceara UFC, Organ & Inorgan Chem Dept, Lab Prod & Proc Technol LPT, Campus Pici, BR-60440900 Fortaleza, Ceara, Brazil.
    Light-Emitting Porphyrin Derivative Obtained from a Subproduct of the Cashew Nut Shell Liquid: A Promising Material for OLED Applications2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 7, article id 1063Article in journal (Refereed)
    Abstract [en]

    In this work, the meso-tetra[4-(2-(3-n-pentadecylphenoxy)ethoxy]phenylporphyrin (H2P), obtained from the cashew nut shell liquid (CNSL), and its zinc (ZnP) and copper (CuP) metallic complexes, were applied as emitting layers in organic light emitting diodes (OLEDs). These compounds were characterized via optical and electrochemical analysis and the electroluminescent properties of the device have been studied. We performed a cyclic voltammetry analysis to determine the Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) energy levels for the porphyrins, in order to select the proper materials to assemble the device. H2P and ZnP presented fluorescence emission band in the red region, from 601 nm to 718 nm. Moreover, we verified that the introduction of bulky substituents hinders the - stacking, favoring the emission in the film. In addition, the strongest emitter, ZnP, presented a threshold voltage of 4 V and the maximum irradiance of 10 W cm(-2) with a current density (J) of 15 mA cm(-2) at 10 V. The CuP complex showed to be a favorable material for the design of OLEDs in the infrared. These results suggest that the porphyrins derived from a renewable source, such as CNSL, is a promising material to be used in organic optoelectronic devices such as OLEDs.

  • 3.
    Filho, Luimar Correa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Schmidt, Susann
    López, Alejandro
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Cogrel, Mathilde
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Leifer, Klaus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Högberg, Hans
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    The Effect of Coating Density on Functional Properties of SiNx Coated Implants2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 20, article id 3370Article in journal (Refereed)
    Abstract [en]

    Ceramic coatings may be applied onto metallic components of joint replacements for improved wear and corrosion resistance as well as enhanced biocompatibility, especially for metal-sensitive patients. Silicon nitride (SiNx) coatings have recently been developed for this purpose. To achieve a high coating density, necessary to secure a long-term performance, is however challenging, especially for sputter deposited SiNx coatings, since these coatings are insulating. This study investigates the time-dependent performance of sputter-deposited SiNx based coatings for joint applications. SiNx coatings with a thickness in the range of 4.3–6.0 µm were deposited by reactive high power impulse magnetron sputtering onto flat discs as well as hip heads made of CoCrMo. SiNx compositional analysis by X-ray photoelectron spectroscopy showed N/Si ratios between 0.8 and 1.0. Immersion of the flat disks in fetal bovine serum solution over time as well as short-term wear tests against ultra-high molecular weight polyethylene (UHMWPE) discs showed that a high coating density is required to inhibit tribocorrosion. Coatings that performed best in terms of chemical stability were deposited using a higher target power and process heating.

  • 4.
    Fowler, Lee
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman-Mägi, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Effect of copper ion concentration on bacteria and cells2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 22, article id 3798Article in journal (Refereed)
    Abstract [en]

    In the oral cavity, dental implants—most often made of commercially pure titanium—come in contact with bacteria, and antibacterial management has been researched extensively to improve patient care. With antibiotic resistance becoming increasingly prevalent, this has resulted in copper being investigated as an antibacterial element in alloys. In this study, the objective was to investigate the copper ion concentrations at which cyto-toxicity is avoided while bacterial inhibition is ensured, by comparing Cu ion effects on selected eukaryotes and prokaryotes. To determine relevant copper ion concentrations, ion release rates from copper and a 10 wt. % Cu Ti-alloy were investigated. Survival studies were performed on MC3T3 cells and Staphylococcus epidermidis bacteria, after exposure to Cu ions concentrations ranging from 9 × 10−3 to 9 × 10−12 g/mL. Cell survival increased from <10% to >90% after 24 h of exposure, by reducing Cu concentrations from 9 × 10−5 to 9 × 10−6 g/mL. Survival of bacteria also increased in the same range of Cu concentrations. The maximum bacteria growth was found at 9 × 10−7 g/mL, probably due to stress response. In conclusion, the minimum inhibitory concentrations of Cu ions for these prokaryotes and eukaryotes were found in the range from 9 × 10−5 to 9 × 10−6 g/mL. Interestingly, the Cu ion concentration correlating to the release rate of the 10 wt. % Cu alloy (9 × 10−8 g/mL) did not kill the bacteria, although this alloy has previously been found to be antibacterial. Further studies should investigate in depth the bacteria-killing mechanism of copper.

  • 5.
    Fowler, Lee
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Masia, Nomsombuluko
    Advanced Materials Division, Mintek, Randburg 2124, South Africa; School of Chemical and Metallurgical Engineering, and DST-NRF Centre of Excellence in Strong Materials, hosted by the University of the Witswatersrand, Johannesburg 2000, South Africa.
    Cornish, Lesley A.
    School of Chemical and Metallurgical Engineering, and DST-NRF Centre of Excellence in Strong Materials, hosted by the University of the Witswatersrand, Johannesburg 2000, South Africa.
    Chown, Lesley H.
    School of Chemical and Metallurgical Engineering, and DST-NRF Centre of Excellence in Strong Materials, hosted by the University of the Witswatersrand, Johannesburg 2000, South Africa.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman-Mägi, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Development of antibacterial Ti-Cux alloys for dental applications: effects of ageing for alloys with up to 10wt%Cu2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 23, article id 4017Article in journal (Refereed)
    Abstract [en]

    Peri-implantitis, a disease caused by bacteria, affects dental implants in patients. It is widely treated with antibiotics, however, with growing antibiotic resistance new strategies are required. Titanium-copper alloys are prospective antibacterial biomaterials, with the potential to be a remedy against peri-implantitis and antibiotic resistance. The aim of this study was to investigate Ti-Cux alloys, exploring how Cu content (up to 10 wt%) and ageing affect the material properties. Electron microscopy, X-ray diffraction, hardness testing, bacteriological culture, and electrochemical testing were employed to characterize the materials. It was found that alloys with above 3 wt% Cu had two phases and ageing increased the volume fraction of Ti2Cu. An un-aged alloy of 5 wt% Cu showed what could be Ti3Cu, in addition to the α-Ti phase. The hardness gradually increased with increased Cu additions, while ageing only affected the alloy with 10 wt% Cu (due to changes in microstructure). Ageing resulted in faster passivation of the alloys. After two hours the aged 10 wt% Cu alloy was the only material with an antibacterial effect, while after six hours, bacteria killing occurred in all alloys with above 5 wt% Cu. In conclusion, it was possible to tune the material and antibacterial properties of Ti-Cux alloys by changing the Cu concentration and ageing, which makes further optimization towards an antibacterial material promising.

  • 6.
    Fowler, Lee
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Van Vuuren, Arno Janse
    Centre for High Resolution Transmission Electron Microscopy, Department of Physics, Nelson Mandela University, 6031 Port Elizabeth, South Africa.
    Goosen, William
    Centre for High Resolution Transmission Electron Microscopy, Department of Physics, Nelson Mandela University, 6031 Port Elizabeth, South Africa.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Öhman-Mägi, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Norgren, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Investigation of copper alloying in a TNTZ-Cux alloy2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 22, article id 3691Article in journal (Refereed)
    Abstract [en]

    Alloying copper into pure titanium has recently allowed the development of antibacterial alloys. The alloying of biocompatible elements (Nb, Ta and Zr) into pure titanium has also achieved higher strengths for a new alloy of Ti-1.6 wt.% Nb-10 wt.% Ta-1.7 wt.% Zr (TNTZ), where strength was closer to Ti-6Al-4V and higher than grade 4 titanium. In the present study, as a first step towards development of a novel antibacterial material with higher strength, the existing TNTZ was alloyed with copper to investigate the resultant microstructural changes and properties. The initial design and modelling of the alloy system was performed using the calculation of phase diagrams (CALPHAD) methods, to predict the phase transformations in the alloy. Following predictions, the alloys were produced using arc melting with appropriate heat treatments. The alloys were characterized using energy dispersive X-ray spectroscopy in scanning transmission electron microscopy (STEM-EDS) with transmission Kikuchi diffraction (TKD). The manufactured alloys had a three-phased crystal structure that was found in the alloys with 3 wt.% Cu and higher, in line with the modelled alloy predictions. The phases included the α-Ti (HCP-Ti) with some Ta present in the crystal, Ti2Cu, and a bright phase with Ti, Cu and Ta in the crystal. The Ti2Cu crystals tended to precipitate in the grain boundaries of the α-Ti phase and bright phase. The hardness of the alloys increased with increased Cu addition, as did the presence of the Ti2Cu phase. Further studies to optimize the alloy could result in a suitable material for dental implants.

  • 7.
    Fritze, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Koller, Christian M.
    TU Wien, Inst Mat Sci & Technol, A-1060 Vienna, Austria.
    von Fieandt, Linus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Malinovskis, Paulius
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Johansson, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Lewin, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Mayrhofer, Paul H.
    TU Wien, Inst Mat Sci & Technol, A-1060 Vienna, Austria.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Influence of Deposition Temperature on the Phase Evolution of HfNbTiVZr High-Entropy Thin Films2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 4, article id 587Article in journal (Refereed)
    Abstract [en]

    In this study, we show that the phase formation of HfNbTiVZr high-entropy thin films is strongly influenced by the substrate temperature. Films deposited at room temperature exhibit an amorphous microstructure and are 6.5 GPa hard. With increasing substrate temperature (room temperature to 275 degrees C), a transition from an amorphous to a single-phased body-centred cubic (bcc) solid solution occurs, resulting in a hardness increase to 7.9 GPa. A higher deposition temperature (450 degrees C) leads to the formation of C14 or C15 Laves phase precipitates in the bcc matrix and a further enhancement of mechanical properties with a peak hardness value of 9.2 GPa. These results also show that thin films follow different phase formation pathways compared to HfNbTiVZr bulk alloys.

  • 8. Fu, Chaochao
    et al.
    Zhou, Xiangbiao
    Wang, Yan
    Xu, Peng
    Xu, Ming
    Wu, Dongping
    Luo, Jun
    Zhao, Chao
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Schottky Barrier Height Tuning via the Dopant Segregation Technique through Low-Temperature Microwave Annealing2016In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 9, no 5, article id 315Article in journal (Refereed)
    Abstract [en]

    The Schottky junction source/drain structure has great potential to replace the traditional p/n junction source/drain structure of the future ultra-scaled metal-oxide-semiconductor field effect transistors (MOSFETs), as it can form ultimately shallow junctions. However, the effective Schottky barrier height (SBH) of the Schottky junction needs to be tuned to be lower than 100 meV in order to obtain a high driving current. In this paper, microwave annealing is employed to modify the effective SBH of NiSi on Si via boron or arsenic dopant segregation. The barrier height decreased from 0.4–0.7 eV to 0.2–0.1 eV for both conduction polarities by annealing below 400 °C. Compared with the required temperature in traditional rapid thermal annealing, the temperature demanded in microwave annealing is ~60 °C lower, and the mechanisms of this observation are briefly discussed. Microwave annealing is hence of high interest to future semiconductor processing owing to its unique capability of forming the metal/semiconductor contact at a remarkably lower temperature.

  • 9.
    Liu, Wenjuan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Hunan Univ Sci & Technol, Sch Mat Sci & Engn, Xiangtan 411201, Peoples R China;Uppsala Univ, Dept Engn Sci, Div Appl Mat Sci, Angstrom Lab, SE-75121 Uppsala, Sweden;Hunan Univ Sci & Technol, Hunan Prov Key Lab Controllable Preparat & Funct, Xiangtan 411201, Peoples R China.
    Huan, Zhiguang
    Chinese Acad Sci, Shanghai Inst Ceram, State Key Lab High Performance Ceram & Superfine, 1295 Dingxi Rd, Shanghai 200050, Peoples R China.
    Xing, Min
    Chinese Acad Sci, Shanghai Inst Ceram, State Key Lab High Performance Ceram & Superfine, 1295 Dingxi Rd, Shanghai 200050, Peoples R China.
    Tian, Tian
    Chinese Acad Sci, Shanghai Inst Ceram, State Key Lab High Performance Ceram & Superfine, 1295 Dingxi Rd, Shanghai 200050, Peoples R China.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Wu, Chengtie
    Chinese Acad Sci, Shanghai Inst Ceram, State Key Lab High Performance Ceram & Superfine, 1295 Dingxi Rd, Shanghai 200050, Peoples R China.
    Zhou, Zhihua
    Hunan Univ Sci & Technol, Hunan Prov Key Lab Controllable Preparat & Funct, Xiangtan 411201, Peoples R China;Hunan Univ Sci & Technol, Sch Chem & Chem Engn, Xiangtan 411201, Peoples R China.
    Chang, Jiang
    Chinese Acad Sci, Shanghai Inst Ceram, State Key Lab High Performance Ceram & Superfine, 1295 Dingxi Rd, Shanghai 200050, Peoples R China.
    Strontium-Substituted Dicalcium Silicate Bone Cements with Enhanced Osteogenesis Potential for Orthopaedic Applications2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 14, article id 2276Article in journal (Refereed)
    Abstract [en]

    Incorporating Sr element in biomaterials for bone implants is an effective way to improve their biological performance, as Sr element has been proved to enhance bone regeneration and depress bone resorption activity. In the present study, we developed a Sr-incorporated dicalcium silicate (C2S) bone cement as a potential candidate for bioactive self-setting bone cement in orthopaedics and stomatology. The Sr-C2S powders containing 0.3-6.8% Sr in molar ratio were prepared by means of chemical co-precipitation, and the results of XRD analysis indicated the incorporation of Sr element into the lattice of C2S. Sr-C2S bone cements, as prepared by mixing the powders with water, have a final setting time of 570 to 594 min, and compressive strength higher than that of C2S bone cement within certain incorporation range. The Sr-C2S bone cements possessed good in vitro bioactivity by inducing apatite formation in simulated body fluid (SBF) within 7 days. Moreover, the proliferation activity of human bone marrow mesenchymal stem cells (hBMSCs) with Sr-C2S bone cements was significantly higher than that with C2S bone cement, and the alkaline phosphatase (ALP) activity of hBMSCs was also enhanced with addition of Sr element in Sr-C2S groups. The Sr-C2S might therefore be a bioactive self-setting material with enhanced biological performance and holds the prospect for application in the bone regeneration area.

  • 10.
    Liu, Xiuwen
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Pujari-Palmer, Michael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Wenner, David
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Procter, Philip
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Insley, Gerard
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. GPBio Ltd, Unit 4D, Western Business Pk, Shannon V14 RW92, Clare, Ireland.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Uppsala Univ, Dept Engn, Appl Mat Sci, S-75121 Uppsala, Sweden.
    Adhesive Cements That Bond Soft Tissue Ex Vivo2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 15, article id 2473Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was to evaluate the soft tissue bond strength of a newly developed, monomeric, biomimetic, tissue adhesive called phosphoserine modified cement (PMC). Two types of PMCs were evaluated using lap shear strength (LSS) testing, on porcine skin: a calcium metasilicate (CS1), and alpha tricalcium phosphate (alpha TCP) PMC. CS1 PCM bonded strongly to skin, reaching a peak LSS of 84, 132, and 154 KPa after curing for 0.5, 1.5, and 4 h, respectively. Cyanoacrylate and fibrin glues reached an LSS of 207 kPa and 33 kPa, respectively. alpha TCP PMCs reached a final LSS of approximate to 110 kPa. In soft tissues, stronger bond strengths were obtained with alpha TCP PMCs containing large amounts of amino acid (70-90 mol%), in contrast to prior studies in calcified tissues (30-50 mol%). When alpha TCP particle size was reduced by wet milling, and for CS1 PMCs, the strongest bonding was obtained with mole ratios of 30-50% phosphoserine. While PM-CPCs behave like stiff ceramics after setting, they bond to soft tissues, and warrant further investigation as tissue adhesives, particularly at the interface between hard and soft tissues.

  • 11.
    Luo, Jun
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Faivre, Julien
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    The Addition of Poly(Vinyl Alcohol) Fibers to Apatitic Calcium Phosphate Cement Can Improve Its Toughness2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 9, article id 1531Article in journal (Refereed)
    Abstract [en]

    Calcium phosphate cements, and in particular hydroxyapatite cements, have been widely investigated for use as bone void fillers due to their chemical similarity to bone and related osteoconductivity. However, they are brittle, which limits their use to non-load-bearing applications. The aim of the current study was to improve the toughness of hydroxyapatite cements through fiber reinforcement. The effect of the addition of hydrophilic, poly(vinyl-alcohol) (PVA) fibers to hydroxyapatite cement was evaluated in terms of mechanical properties, including compressive strength, diametral tensile strength and toughness (work of fracture), as well as setting time, phase composition and cement morphology. The fiber reinforcement enhanced the fracture resistance of the hydroxyapatite cement, but also simultaneously reduced the compressive strength and setting time of the cements. However, cement with 5 wt % of fibers (of the powder component) could be considered a good compromise, with a compressive strength of 46.5 +/- 4.6 MPa (compared to 62.3 +/- 12.8 MPa of that without fibers), i.e., still much greater than that of human trabecular bone (0.1-14 MPa). A significantly higher diametral tensile strength (9.2 +/- 0.4 MPa) was found for this cement compared to that without fibers (7.4 +/- 1.5 MPa). The work of fracture increased four times to 9.1 +/- 1.5 kJ/m(2) in comparison to the pristine apatite. In summary, the hydroxyapatite cements could be reinforced by suitable amounts of PVA fibers, which resulted in enhancing the material's structural integrity and ductility, and increased the material's resistance to cracking.

  • 12.
    Oltean, Viorica-Alina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Renault, Stéven
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Valvo, Mario
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Brandell, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Sustainable Materials for Sustainable Energy Storage: Organic Na Electrodes2016In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 9, no 3, article id 142Article, review/survey (Refereed)
    Abstract [en]

    In this review, we summarize research efforts to realize Na-based organic materials for novel battery chemistries. Na is a more abundant element than Li, thereby contributing to less costly materials with limited to no geopolitical constraints while organic electrode materials harvested from biomass resources provide the possibility of achieving renewable battery components with low environmental impact during processing and recycling. Together, this can form the basis for truly sustainable electrochemical energy storage. We explore the efforts made on electrode materials of organic salts, primarily carbonyl compounds but also Schiff bases, unsaturated compounds, nitroxides and polymers. Moreover, sodiated carbonaceous materials derived from biomasses and waste products are surveyed. As a conclusion to the review, some shortcomings of the currently investigated materials are highlighted together with the major limitations for future development in this field. Finally, routes to move forward in this direction are suggested.

  • 13. Pfeiffer, Tobias V.
    et al.
    Kedia, Puneet
    Messing, Maria E.
    Valvo, Mario
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Schmidt-Ott, Andreas
    Precursor-Less Coating of Nanoparticles in the Gas Phase2015In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 8, no 3, p. 1027-1042Article in journal (Refereed)
    Abstract [en]

    This article introduces a continuous, gas-phase method for depositing thin metallic coatings onto (nano)particles using a type of physical vapor deposition (PVD) at ambient pressure and temperature. An aerosol of core particles is mixed with a metal vapor cloud formed by spark ablation by passing the aerosol through the spark zone using a hollow electrode configuration. The mixing process rapidly quenches the vapor, which condenses onto the core particles at a timescale of several tens of milliseconds in a manner that can be modeled as bimodal coagulation. Gold was deposited onto core nanoparticles consisting of silver or polystyrene latex, and silver was deposited onto gold nanoparticles. The coating morphology depends on the relative surface energies of the core and coating materials, similar to the growth mechanisms known for thin films: a coating made of a substance having a high surface energy typically results in a patchy coverage, while a coating material with a low surface energy will normally "wet" the surface of a core particle. The coated particles remain gas-borne, allowing further processing.

  • 14.
    Pujari-Palmer, Michael
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. 0000-0001-7004-2853.
    Guo, Hua
    Stockholm Univ, Dept Mat & Environm Chem, Stockholm, Sweden.
    Wenner, David
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Autefage, Hélène
    Karolinska Inst, Dept Med Biochem & Biophys, Stockholm, Sweden.
    Spicer, Christopher D.
    Karolinska Inst, Dept Med Biochem & Biophys, Stockholm, Sweden.
    Stevens, Molly M.
    Karolinska Inst, Dept Med Biochem & Biophys, Stockholm, Sweden; Imperial Coll London, Dept Bioengn, Dept Mat, London, England; Imperial Coll London, Inst Biomed Engn, London, England.
    Omar, Omar
    Univ Gothenburg, Inst Clin Sci, Dept Biomat, Gothenburg, Sweden.
    Thomsen, Peter
    Univ Gothenburg, Inst Clin Sci, Dept Biomat, Gothenburg, Sweden.
    Edén, Mattias
    Stockholm Univ, Dept Mat & Environm Chem, Stockholm, Sweden.
    Insley, Gerard
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Procter, Philip
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    A Novel Class of Injectable Bioceramics that Glue Tissues and Biomaterials2018In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 11, no 12, article id 2492Article in journal (Refereed)
    Abstract [en]

    Calcium phosphate cements (CPCs) are clinically effective void fillers that are capable of bridging calcified tissue defects and facilitating regeneration. However, CPCs are completely synthetic/inorganic, unlike the calcium phosphate that is found in calcified tissues, and they lack an architectural organization, controlled assembly mechanisms, and have moderate biomechanical strength, which limits their clinical effectiveness. Herein, we describe a new class of bioinspired CPCs that can glue tissues together and bond tissues to metallic and polymeric biomaterials. Surprisingly, alpha tricalcium phosphate cements that are modified with simple phosphorylated amino acid monomers of phosphoserine (PM-CPCs) bond tissues up to 40-fold stronger (2.5–4 MPa) than commercial cyanoacrylates (0.1 MPa), and 100-fold stronger than surgical fibrin glue (0.04 MPa), when cured in wet-field conditions. In addition to adhesion, phosphoserine creates other novel properties in bioceramics, including a nanoscale organic/inorganic composite microstructure, and templating of nanoscale amorphous calcium phosphate nucleation. PM-CPCs are made of the biocompatible precursors calcium, phosphate, and amino acid, and these represent the first amorphous nano-ceramic composites that are stable in liquids.

  • 15.
    Qian, Zhao
    et al.
    Shandong Univ, Minist Educ, Key Lab Liquid Solid Struct Evolut & Proc Mat, Shenzhen 518057, Peoples R China;Shandong Univ, Shenzhen Inst, Shenzhen 518057, Peoples R China.
    Zhang, Hongni
    Shandong Management Univ, Jinan 250100, Shandong, Peoples R China.
    Jiang, Guanzhong
    Shandong Univ, Minist Educ, Key Lab Liquid Solid Struct Evolut & Proc Mat, Shenzhen 518057, Peoples R China;Shandong Univ, Shenzhen Inst, Shenzhen 518057, Peoples R China.
    Bai, Yanwen
    Shandong Univ, Minist Educ, Key Lab Liquid Solid Struct Evolut & Proc Mat, Shenzhen 518057, Peoples R China;Shandong Univ, Shenzhen Inst, Shenzhen 518057, Peoples R China.
    Ren, Yingying
    Shandong Univ, Minist Educ, Key Lab Liquid Solid Struct Evolut & Proc Mat, Shenzhen 518057, Peoples R China;Shandong Univ, Shenzhen Inst, Shenzhen 518057, Peoples R China.
    Du, Wenzheng
    Shandong Univ, Minist Educ, Key Lab Liquid Solid Struct Evolut & Proc Mat, Shenzhen 518057, Peoples R China;Shandong Univ, Shenzhen Inst, Shenzhen 518057, Peoples R China.
    Ahuja, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Ab Initio Screening of Doped Mg(AlH4)(2) Systems for Conversion-Type Lithium Storage2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 16, article id 2599Article in journal (Refereed)
    Abstract [en]

    In this work, we have explored the potential applications of pure and various doped Mg(AlH4)(2) as Li-ion battery conversion electrode materials using density functional theory (DFT) calculations. Through the comparisons of the electrochemical specific capacity, the volume change, the average voltage, and the electronic bandgap, the Li-doped material is found to have a smaller bandgap and lower average voltage than the pure system. The theoretical specific capacity of the Li-doped material is 2547.64 mAhg(-1) with a volume change of 3.76% involving the electrode conversion reaction. The underlying reason for property improvement has been analyzed by calculating the electronic structures. The strong hybridization between Lis-state with H s-state influences the performance of the doped material. This theoretical research is proposed to help the design and modification of better light-metal hydride materials for Li-ion battery conversion electrode applications.

  • 16.
    Saketi, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Dalarna Univ, Mat Sci, SE-79188 Falun, Sweden.
    Odelros, Stina
    Sandvik Coromant, R&D, SE-12680 Stockholm, Sweden.
    Ostby, Jonas
    Sandvik Coromant, R&D, SE-12680 Stockholm, Sweden.
    Olsson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Dalarna Univ, Mat Sci, SE-79188 Falun, Sweden.
    Experimental Study of Wear Mechanisms of Cemented Carbide in the Turning of Ti6Al4V2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 17, article id 2822Article in journal (Refereed)
    Abstract [en]

    Titanium and titanium alloys such as Ti-6Al-4V are generally considered as difficult-to-machine materials. This is mainly due to their high chemical reactivity, poor thermal conductivity, and high strength, which is maintained at elevated temperatures. As a result, the cutting tool is exposed to rather extreme contact conditions resulting in plastic deformation and wear. In the present work, the mechanisms behind the crater and flank wear of uncoated cemented carbide inserts in the turning of Ti6Al4V are characterized using high-resolution scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and high-resolution Auger electron spectroscopy (AES).The results show that, for combinations of low cutting speeds and feeds, crater and flank wear were found to be controlled by an attrition wear mechanism, while for combinations of medium to high cutting speeds and feeds, a diffusion wear mechanism was found to control the wear. For the latter combinations, high-resolution SEM and AES analysis reveal the formation of an approximately 100 nm thick carbon-depleted tungsten carbide (WC)-layer at the cemented carbide/Ti6Al4V interface due to the diffusion of carbon into the adhered build-up layers of work material on the rake and flank surfaces.

  • 17.
    Saketi, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. Dalarna Univ, Mat Tech, SE-79188 Falun, Sweden.
    Östby, Jonas
    AB Sandvik Coromant, R&D, SE-68385 Sandviken, Sweden.
    Bexell, Ulf
    Dalarna Univ, Mat Tech, SE-79188 Falun, Sweden.
    Olsson, Mikael
    Dalarna Univ, Mat Tech, SE-79188 Falun, Sweden.
    A Methodology to Systematically Investigate the Diffusion Degradation of Cemented Carbide during Machining of a Titanium Alloy2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 14, p. 1-17, article id 2271Article in journal (Refereed)
    Abstract [en]

    Using Ti6Al4V as a work material, a methodology to systematically investigate the diffusion degradation of cemented carbide during machining is proposed. The methodology includes surface characterization of as-tested worn inserts, wet etched worn inserts, metallographic cross-sectioned worn inserts as well as the back-side of the produced chips. Characterization techniques used include scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Auger electron spectroscopy (AES) and time of flight secondary ion mass spectroscopy (ToF-SIMS). The results show that the characterization of wet etched worn inserts gives quick and useful information regarding the diffusion degradation of cemented carbide, in the present work the formation of a fine crystalline W layer (carbon depleted WC layer) at the tool-work material interface. The present study also illuminates the potential of AES analysis when it comes to analyzing the degradation of cemented carbide in contact with the work material during machining. The high surface sensitivity in combination with high lateral resolution makes it possible to analyze the worn cemented carbide surface on a sub-mu m level. Especially AES sputter depth profiling, resulting in detailed information of variations in chemical composition across interfaces, is a powerful tool when it comes to understanding diffusion wear. Finally, the present work illustrates the importance of analyzing not only the worn tool but also the produced chips. An accurate characterization of the back-side of the chips will give important information regarding the wear mechanisms taking place at the tool rake face chip interface. Surface analysis techniques such as AES and ToF-SIMS are well suited for this type of surface characterization.

  • 18.
    Skjöldebrand, Charlotte
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Schmidt, Susann
    Linkoping Univ, Thin Film Phys Div, Dept Phys Chem & Biol IFM, S-58183 Linkoping, Sweden..
    Vuong, Vicky
    McMaster Univ, Dept Mat Sci & Engn, Hamilton, ON L8S 4L7, Canada..
    Pettersson, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Grandfield, Kathryn
    McMaster Univ, Dept Mat Sci & Engn, Hamilton, ON L8S 4L7, Canada..
    Hogberg, Hans
    Linkoping Univ, Thin Film Phys Div, Dept Phys Chem & Biol IFM, S-58183 Linkoping, Sweden..
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Persson, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Influence of Substrate Heating and Nitrogen Flow on the Composition, Morphological and Mechanical Properties of SiNx Coatings Aimed for Joint Replacements2017In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 10, no 2Article in journal (Refereed)
    Abstract [en]

    Silicon nitride (SiNx) coatings are promising for joint replacement applications due to their high wear resistance and biocompatibility. For such coatings, a higher nitrogen content, obtained through an increased nitrogen gas supply, has been found to be beneficial in terms of a decreased dissolution rate of the coatings. The substrate temperature has also been found to affect the composition as well as the microstructure of similar coatings. The aim of this study was to investigate the effect of the substrate temperature and nitrogen flow on the coating composition, microstructure and mechanical properties. SiNx coatings were deposited onto CoCrMo discs using reactive high power impulse magnetron sputtering. During deposition, the substrate temperatures were set to 200 degrees C, 350 degrees C or 430 degrees C, with nitrogen-to-argon flow ratios of 0.06, 0.17 or 0.30. Scanning and transmission electron spectroscopy revealed that the coatings were homogenous and amorphous. The coatings displayed a nitrogen content of 23-48 at.% (X-ray photoelectron spectroscopy). The surface roughness was similar to uncoated CoCrMo (p = 0.25) (vertical scanning interferometry). The hardness and Young's modulus, as determined from nanoindentation, scaled with the nitrogen content of the coatings, with the hardness ranging from 12 +/- 1 GPa to 26 +/- 2 GPa and the Young's moduli ranging from 173 +/- 8 GPa to 293 +/- 18 GPa, when the nitrogen content increased from 23% to 48%. The low surface roughness and high nano-hardness are promising for applications exposed to wear, such as joint implants.

  • 19.
    Tian, Yuan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Larsson, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Effect by diamond surface modification on biomolecular adhesion2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 6, article id 865Article in journal (Refereed)
    Abstract [en]

    Diamond, as material, show very attractive properties. They include superior electronic properties (when doped), chemical inertness, controllable surface termination, and biocompatibility. It is thus clear that surface termination is very important for those applications where the implant material is based on diamond. The present theoretical work has focused on the effect of diamond surface termination, in combination with type of surface plane, on the adhesion of important biomolecules for vascularization and bone regeneration. These biomolecules include Arginine-Glycine-Aspartic acid (RGD), Chitosan, Heparin, Bone Morphogenetic Protein 2 (BMP2), Angiopoietin 1 (AGP1), Fibronectin and Vascular Endothelial Growth Factor (VEGF). The various surface planes are diamond diamond (100)-2x1 and (111). The theoretical results show that the non-covalent binding of these biomolecules is in proportion with their molecular weights. Moreover, three groups of biomolecules were observed for both types of surface planes. The most strongly binding biomolecule was the BMP2 molecule. The smaller polypeptides (RGD, Chitosan and Heparin) formed a less strongly binding group. Finally, the biomolecules VEGF, Fibronectin and Angiopoietin showed bond strengths numerically in between the other two groups (thereby forming a third group). Moreover, the (111) surface was generally observed to display a stronger bonding of the biomolecules, as compared with the (100)-2x1 surface.

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