Here we report syntheses and study of composite solid polymer electrolytes (SPEs) based on a poly(ethylene glycol)-in-Li triflate material that contains an organic-inorganic composite (OIC) in which boron species are incorporated into a silica network. The structure and properties of the SPEs synthesized were characterized by scanning transmission electron microscopy (STEM), 29 Si, 11 B and 13 C solid state NMR, differential scanning calorimetry, and impedance spectroscopy. STEM allowed assessment of OIC particles in their native environment without removal of an organic component. The Lewis acid tricoordinate boron sites formed in OIC are proposed to have a stronger interaction with triflate anions than silica sites, which results in enhanced lithium ion conductivity and Li transference numbers at optimal boron concentrations. The optimum triethyl borate (TEB) concentration also leads to formation of smaller (higher surface area) OIC particles, which expose more boron sites to triflate anions. The SPE sample prepared with 10 mol% TEB exhibited a conductivity of 4.3 Â 10 À5 S cm À1 and a Li transference number of 0.89, which represents nearly single-ion conductor behaviour for the salt-in-polymer-borosilicate composite.
Ionic liquids bolster the conductivity of hybrid composite polymer electrolytes based on poly(ethylene glycols) and organic–inorganic silica nanoparticles formed in situ.
Nanoparticle-based
contrast agents, when used in concert with imaging
modalities such as computed tomography (CT), enhance the visualization
of tissues and boundary interfaces. However, the ability to determine
the physiological state of the tissue via the quantitative assessment
of biochemical or biomechanical properties remains elusive. We report
the synthesis and characterization of tantalum oxide (Ta2O5) nanoparticle (NP) contrast agents for rapid, nondestructive,
and quantitative contrast-enhanced computed tomography (CECT) to assess
both the glycosaminoglycan (GAG) content and the biomechanical integrity
of human metacarpal phalangeal joint (MCPJ) articular cartilage. Ta2O5 NPs 3–6 nm in diameter and coated with
either nonionic poly(ethylene) glycol (PEG) or cationic trimethylammonium
ligands readily diffuse into both healthy and osteoarthritic MCPJ
cartilage. The CECT attenuation for the cationic and neutral NPs correlates
with the glycosaminoglycan (GAG) content (R
2 = 0.8975, p < 0.05 and 0.7054, respectively)
and the equilibrium modulus (R
2 = 0.8285, p < 0.05 and 0.9312, p < 0.05, respectively).
The results highlight the importance of the surface charge and size
in the design of NP agents for targeting and imaging articular cartilage.
Further, nanoparticle CECT offers the visualization of both soft tissue
and underlying bone unlike plain radiography, which is the standard
for imaging bone in musculoskeletal diseases, and the ability to provide
a real-time quantitative assessment of both hard and soft tissues
to provide a comprehensive image of the disease stage, as demonstrated
herein.
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