BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 Organic(oil) phase Ae CaYCe: Figure 3. Vaterite spheroids formed from a microemulsion f octane: SDS: CaHCO3(71: 4: 25 wt %) Note the complex SDS surface patterning and uniform size of the spheres. Scale bar 10 um(Reproduced by permission from ref 14) Microemulsion mineralization OIr Figure 2. Porous vaterite microspheres waporatka feil attrated when the carbon dioxide slowly prec pate min fallowing release of tapped cOh Green et al. 2002) · Model of process 2. Loss of CO2 in solution increases the concentration of carbonate ions and thus the supersaturation r interface 1. Dissolved CO2 in the supersaturated solution separates into bubbles that are trapped at the oil-water interface 3. local supersaturation is highest next to CO2 bubbles, so first calcium carbonate precipitation occurs here Bubbles trapped at oil/water interface dictate foamed surface morphology of inorganic structure Vaterite formed in this process dictated by ostwald's rule of stages o Polymorph with highest solubility preferentially forms under kinetically-controlled Lecture 11-Inorganic biomaterials 9of12BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Lecture 11 – Inorganic Biomaterials 9 of 12 Aq CaHCO3 SDS Organic (oil) phase Microemulsion mineralization (Green et al. 2002) • Model of process:6 1. Dissolved CO2 in the supersaturated solution separates into bubbles that are trapped at the oil-water interface 2. Loss of CO2 in solution increases the concentration of carbonate ions and thus the supersaturation 3. local supersaturation is highest next to CO2 bubbles, so first calcium carbonate precipitation occurs here • Bubbles trapped at oil/water interface dictate ‘foamed’ surface morphology of inorganic structure • Vaterite formed in this process dictated by Ostwald’s rule of stages: o Polymorph with highest solubility preferentially forms under kinetically-controlled conditions