Structure of SrO/CaO Substituted BioglassesJincheng Du, University of North Texas, DMR 0907593

Strontium ions have been found to have the unusual dual effects of promoting bone growth and inhibiting bone absorption. Stontium/Calcium substitution thus becomes an effective way to improve bioactivity of bioactive glasses. The structure of these glasses are however largely unknown. We have obtained important structure and dynamic information of strontium substituted 45S5 bioactive glasses using molecular dynamics simulations.

It was found that strontium has slightly higher coordination number and longer Sr-O bond distance than calcium. Strontium substitution leads to an increase of density and molar volume. In these bioactive glasses, phosphate ions mostly form isolated orthophosphate groups. In related phosphosilicate glasses, transition metal ions were found to be preferentially surrounded by phosphate groups.

Fig. 1 (a) Validation of structure model from MD by comparing with neutron diffraction data, (b) Effect of SrO on glass density, (c) local environment of Sr, (c) isolated orthophosphate phosphate groups.

Ref: 1. Xiang and Du, Chem. Materials 23 (2011) 2703. 2. Du et al, J. Am. Ceram. Soc. 94 (2011) 2393.

Introducing Material Science to High School Students Jincheng Du, University of North Texas, DMR 0907593

We hosted the second Materials Camp for high school students this summer (July 18-20). Over 35 students from across Texas, California and one international participant from Canada participated the three day events. We led on the module of glass and ceramic materials, in which presented an hands module on glass melting on soda lime silicate glass, with composition similar to bioactive glasses.

As the faculty advisor to the Material Advantage UNT Chapter, Dr. Du supervised organization of the Summer Camp. Graduate student Ye Xiang supported this project led the Ceramic and Glass module of the Camp. In addition, Dr. Du and Ye has visited several leading bioglass and biomaterial research groups in UK, with the trip partly supported by NSF IMI of new functionality of glass.

Graduate student Ye Xiang is showing the summer camp students to prepare raw materials (top) and demonstrating pouring of glass melts (bottom).