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

Cyclic phosphonitrilic halides are formed rapidly and in high yield in a controllable multi-step process including the step of reacting a nitrogenous base (e.g. pyridine) with a phosphorus tetrahalide (e.g. phosphorus pentachloride) in a suitable inert liquid reaction medium (e.g. monochlorobenzene) to form a complex and in a subsequent step reacting this complex with an ammonium halide (e.g. ammonium chloride) at a temperature above about 90° C. up to the reflux temperature of the reaction medium to form cyclic phosphonitrilic halides, mainly trimer.

Pyridine phosphonitrilic halide trimer process

Metallocene and other transition metal derivatives of phosphazene oligomers and polymers: A retrospective summary

An immunoadjuvant soluble phosphazene polyelectrolyte is disclosed. In one embodiment, the polymeric adjuvant is a poly(organophosphazene) with (i) ionized or ionizable pendant groups that contain, for example, carboxylic acid, sulfonic acid, or hydroxyl moieties, and (ii) pendant groups that are susceptible to hydrolysis under the conditions of use, to impart biodegradability to the polymer.

Polyphosphazenes useful as immunoadjuvants

: Cyclic and high polymeric phosphazenes that bear 3-(4-oxyphenyl)-l- phenyl-2-propen-l-one (4-oxychalcone) side groups have been prepared in order to study their photochemical behavior. Small molecule cyclic trimers of the general formula N3P3R5R' where R= phenoxy, 2,2,2-trifluoroethoxy, chloro and 4- oxychalcone and R'= 4-oxychalcone were synthesized in order to model the crosslinking reactions at the high polymer level. Single-substituent and cosubstituent polymeric phosphazenes NPRR'2n' where R= phenoxy, 2,2,2- trifluoroethoxy or 4-oxychalcone, and R'= 4-oxychalcone were also prepared. Their photolytic crosslinking was followed by ultraviolet spectroscopy.

The Synthesis of Photocrosslinkable Chalcone-Bearing Polyphosphazenes

Polyphosphazenes are inorganic-organic high polymers with a backbone of alternating phosphorus and nitrogen atoms and two organic or organometallic side groups attached to each phosphorus. Most of these polymers are synthesized by macromolecular substitution reactions carried out on poly(dichlorophosphazene), (NPCl2)n. The chlorine substitution reactions involve alkoxides, aryloxides, primary or secondary amines, or a range of organometallic reagents. Structural variations are accomplished via the use of one, two, or more different nucleophiles and substituents along the polymer chain and by the employment of reagent size and reactivity to control polymer properties and emphasize specific uses. Applications have been developed for these polymers as elastomers, thermoplastics, biostable or bioerodible medical materials, fire-resistant lithium battery electrolytes, films, or foams, and gas and liquid separation membranes.

Harry R. Allcock

Papers

Pyridine phosphonitrilic halide trimer process

Metallocene and other transition metal derivatives of phosphazene oligomers and polymers: A retrospective summary

Polyphosphazenes useful as immunoadjuvants

The Synthesis of Photocrosslinkable Chalcone-Bearing Polyphosphazenes

Polyphosphazenes as an Example of the Element-Blocks Approach to New Materials