There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Hydrogels for tissue engineering.

https://yunus.hacettepe.edu.tr/~damlacetin/kmu407/index_dosyalar/4.%20makale.pdf

Biodegradable polymers as biomaterials

Hydrogels in pharmaceutical formulations.

Lithium (Li) metal is an ideal anode material for rechargeable batteries due to its extremely high theoretical specific capacity (3860 mA h g−1), low density (0.59 g cm−3) and the lowest negative electrochemical potential (−3.040 V vs. the standard hydrogen electrode). Unfortunately, uncontrollable dendritic Li growth and limited Coulombic efficiency during Li deposition/stripping inherent in these batteries have prevented their practical applications over the past 40 years. With the emergence of post-Li-ion batteries, safe and efficient operation of Li metal anodes has become an enabling technology which may determine the fate of several promising candidates for the next generation energy storage systems, including rechargeable Li–air batteries, Li–S batteries, and Li metal batteries which utilize intercalation compounds as cathodes. In this paper, various factors that affect the morphology and Coulombic efficiency of Li metal anodes have been analyzed. Technologies utilized to characterize the morphology of Li deposition and the results obtained by modelling of Li dendrite growth have also been reviewed. Finally, recent development and urgent need in this field are discussed.

Lithium metal anodes for rechargeable batteries

Photochromic spiropyrans were linked to polyphosphazenes through diethyleneoxy or triethyleneoxy spacer units. The reversion of photogenerated merocyanine groups to spiropyran units in these polymers in various solvents or in the solid state was investigated. Unlike the behavior of the free small-molecule spiropyran, the merocyanine relaxation in the polymeric species showed deviations from a first-order relationship in solution and in the solid state. Relaxations in THF and in the solid state were modeled by a biexponential process

Photochromic polyphosphazenes with spiropyran units

Small-molecule phosphazene rings as models for high polymeric chains

La polymerisation thermique, par ouverture de cycle du pentachlorocyclotrithiophosphazene Cl 5 N 3 P 2 S donne le polymere (SCl=N•PCl 2 =N-PCl 2 =N) n . Ce polymere etant sensible a l'humidite, les atomes de chlore sont remplaces par des groupes aryloxy par substitution nucleophile

Poly(thiophosphazenes): new inorganic macromolecules with backbones composed of phosphorus, nitrogen, and sulfur atoms

Conformation, bonding, and flexibility in short-chain linear phosphazenes

A series of mixed-substituent poly(organophosphazenes) with ethyleneoxy side groups has been synthesized. These polymers possess multiple electron-donor coordination sites that can form complexes with metal salts and generate “solid electrolyte” behavior. The polymers were characterized by 31P, 1H, and 13C NMR spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and elemental analysis. All the mixed-substituent polymers have low glass transition temperatures, from −70 to −56 °C, as well as at least one melting transition. Several polymer−lithium triflate complexes were examined by impedance analysis. The maximum conductivities for these polymers ranged from 1.6 × 10-6 to 3.9 × 10-5 S cm-1.

Harry R. Allcock

Papers

Photochromic polyphosphazenes with spiropyran units

Small-molecule phosphazene rings as models for high polymeric chains

Poly(thiophosphazenes): new inorganic macromolecules with backbones composed of phosphorus, nitrogen, and sulfur atoms

Conformation, bonding, and flexibility in short-chain linear phosphazenes

Synthesis of polyphosphazenes with ethyleneoxy-containing side groups: New solid electrolyte materials