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

: Three classes of poly(organophosphazenes) have been synthesized with biomedical uses in view. These include hydrophobic poly(fluoroalkoxyphosphazenes), such as [NP(OCH 2 CF 3 ) 2 ], poly(amino acid ester phosphazenes), such as [NP(NHCH 2 COOC 2 H 5 ) 2 ] n , and coordination complexes of the type [NP(NHCH 3 ) 2 ] x (PtC1 2 ) y . The platinum-containing species were designed as water-soluble polymeric anticancer agents, and the amino acid ester substituted polyphosphazenes were designed to degrade hydrolytically to amino acid, phosphate, alcohol, and ammonia. The structure and reactions of the polymers are discussed.

Poly(organophosphazenes) designed for biomedical uses

Recent advances in polyphosphazene chemistry and related areas are used as examples of approaches that may be applicable to other inorganic/organometallic polymer systems. Emphasis is placed on the tailored synthesis of macromolecules via ring-opening polymerization and macromolecular substitution to generate properties, such as elasticity, solid ionic conductivity, electronic conductivity, biological compatibility or activity, and liquid crystalline or non-linear optical behavior.

The Current State of the Art in the Synthesis of Inorganic and Organometallic Polymers

The mass spectra of a series of monalkylpentachlotriphosphazenes

Di-alkylated phosphazene oligomers of the general formula: (NP(X2))..n NPRR' wherein X represents chloride, bromide, or iodide, R and R' represent a linear or branched, saturated or unsaturated hydrocarbon and n represents an integer from 2 to 8, are prepared by reacting, in a nonoxidizing atmosphere, a perhalopolyphosphazene, a Grignard reagent and a cuprous complex in solution, followed by the addition of alkyl iodide or an activated alkyl halide. Polymers, useful as high-temperature elastomers, are prepared from the above oligomers by heating them at a temperature from about 200° C. to about 300° C., followed by a reaction with an amine, metal alkoxide, or a metal aryloxide at a temperature from 20° C. to 200° C.

Dialkylated phosphazene oligomers and method of preparation thereof

Hydroxyapatite formed from low temperature setting calcium phosphate cements (CPC) are currently been used for various orthopaedic applications. CPCs are attractive candidates for the development of scaffolds for bone tissue engineering, since they are moldable, resorbable, set at physiological temperature without the use of toxic chemicals, and can be processed in an operating room setting. However they may have mechanical disadvantages which seriously limit them to non-load bearing orthopaedic applications. The aim of the present study was to develop composites from polyphosphazenes and calcium deficient hydroxyapatite precursors to form poorly crystalline hydroxyapatite-polymer composites. Composites were formed from calcium deficient hydroxyapatite precursors (Ca/P–1.5, 1.6) and biodegradable polyphosphazenes, poly[bis(ethyl alanato)phosphazene] (PNEA) and poly[(50%ethyl alanato) (50%methyl phenoxy)phosphazene] (PNEA50mPh50) at physiological temperature. The results demonstrated that poorly crystalline hydroxyapatite that resembled the mineral component of bone was formed in the presence of biodegradable polyphosphazenes. The surface morphology of all the four composites was identical with a porous microstructure. The composites supported the adhesion and proliferation of osteoblast like MC3T3-E1 cells making them potential candidates for bone tissue engineering.

Harry R. Allcock

Papers

Poly(organophosphazenes) designed for biomedical uses

The Current State of the Art in the Synthesis of Inorganic and Organometallic Polymers

The mass spectra of a series of monalkylpentachlotriphosphazenes

Dialkylated phosphazene oligomers and method of preparation thereof

Development of Novel Biodegradable Amino Acid Ester Based Polyphosphazene-Hydroxyapatite Composites for Bone Tissue Engineering