The purpose of the current study was to evaluate the effect of etching with potassium hydrogen difluoride (KHF) and ammonium hydrogen difluoride (NHHF) on the bond strength of a self-polymerizing methyl methacrylate resin (MMA-TBB) bonded to zirconia. Zirconia disks were prepared using the following surface treatment: no treatment, alumina blasting, and etching with KHF or NHHF. The specimens were bonded with the MMA-TBB. The shear bond (Ø=5 mm) strength was measured. The surface free energies of the specimens were determined by measuring contact angles. The KHF and NHHF groups exhibited higher shear bond strength and surface free energy than did the alumina blasting and no treatment groups. Compared with alumina blasting, etching with KHF and NHHF exhibited superior bonding ability of mechanical retention to zirconia.
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http://dx.doi.org/10.4012/dmj.2018-152 | DOI Listing |
Phys Chem Chem Phys
January 2025
Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
We present first-principles molecular dynamics simulations of oxygen difluoride impinging upon the monohydrogenated Si{001}(2 × 1) surface. Adsorption occurred in fewer than 10% of our computed trajectories, but in each reactive case the initial step involved partial dissociation to yield an adsorbed fluorine atom and a free oxygen monofluoride radical. In one trajectory, the adsorbed fluorine atom displaced a hydrogen atom into an unusual Si-H-Si bridge position, consistent with three-centre two-electron bonding.
View Article and Find Full Text PDFACS Appl Mater Interfaces
November 2024
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
Two donor-acceptor dyes with an -phenylene-linked carbazole electron donor and a benzothiazole-fused boron heterocyclic acceptor were designed, synthesized, and spectroscopically investigated. Due to the steric effects of boron heterocyclic units, the dyes demonstrate different conformations in the crystalline state. The presence of numerous hydrogen-bonding intermolecular interactions and the very weak π-π stacking in the molecular packing results in intense solid-state emission with photoluminescence quantum yields of 40 and 18% for crystals and 50 and 42% for host-based light-emitting layers.
View Article and Find Full Text PDFArch Razi Inst
February 2024
Department of Pharmaceutical Analysis, GITAM Institute of Pharmacy, Gandhi Institute of Technology and Management (GITAM) (Deemed to be University), Visakhapatnam, Pin code: 530 045, Andhra Pradesh (State), India.
Selenium is a class 2B element according to the International Council for Harmonization Q3D guidelines. Selenium sulfide is an anti-infective agent with antifungal and antibacterial properties used to treat dandruff and seborrheic dermatitis. The literature survey revealed that most of the analytical techniques to estimate selenium were time-consuming and/or required high skill levels.
View Article and Find Full Text PDFACS Appl Mater Interfaces
August 2024
Department of Chemical Sciences, University of Naples Federico II, via Cintia 21, 80126 Naples, Italy.
The self-assembly of proteins and peptides into fibrillar amyloid aggregates is a highly promising route to define the next generation of functional nanomaterials. Amyloid fibrils, traditionally associated with neurodegenerative diseases, offer exceptional conformational and chemical stability and mechanical properties, and resistance to degradation. Here, we report the development of catalytic amyloid nanomaterials through the conjugation of a miniaturized artificial peroxidase (FeMC6*a) to a self-assembling amyloidogenic peptide derived from human transthyretin, TTR(105-115), whose sequence is YTIAALLSPYS.
View Article and Find Full Text PDFACS Appl Mater Interfaces
May 2024
Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pune 411008, India.
Ionic cocrystals with hydrogen bonding can form exciting materials with enhanced optical and electronic properties. We present a highly moisture-stable ammonium salt cocrystal [CHCHCH(CH)NH][CHCHCH(CH)NH][PF] () crystallizing in the polar monoclinic 2 space group. The asymmetry in was induced by its chiral substituents, while the polar order and structural stability were achieved by using the octahedral PF anion and the consequent formation of salt cocrystal.
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