TY  - JOUR
A1  - Shkilnyy, Andriy
A1  - Schöne, Stefanie
A1  - Rumplasch, Claudia
A1  - Uhlmann, Annett
A1  - Hedderich, Annett
A1  - Günter, Christina
A1  - Taubert, Andreas
T1  - Calcium phosphate mineralization with linear poly(ethylene imine) a time-resolved study
JF  - Colloid and polymer science : official journal of the Kolloid-Gesellschaft
N2  - We have earlier shown that linear poly(ethylene imine) (LPEI) is an efficient growth modifier for calcium phosphate mineralization from aqueous solution (Shkilnyy et al., Langmuir, 2008, 24 (5), 2102). The current study addresses the growth process and the reason why LPEI is such an effective additive. To that end, the solution pH and the calcium and phosphate concentrations were monitored vs. reaction time using potentiometric, complexometric, and photometric methods. The phase transformations in the precipitates and particle morphogenesis were analyzed by X-ray diffraction and transmission electron microscopy, respectively. All measurements reveal steep decreases of the pH, calcium, and phosphate concentrations along with a rapid precipitation of brushite nanoparticles early on in the reaction. Brushite transforms into hydroxyapatite (HAP) within the first 2 h, which is much faster than what is reported, for example, for calcium phosphate precipitated with poly(acrylic acid). We propose that poly(ethylene imine) acts as a proton acceptor (weak buffer), which accelerates the transformation from brushite to HAP by taking up the protons that are released from the calcium phosphate precipitate during the phase transformation.
KW  - Calcium phosphate
KW  - Polyethylene imine
KW  - Mineralization
KW  - Kinetics
Y1  - 2011
U6  - https://doi.org/10.1007/s00396-011-2403-2
SN  - 0303-402X
VL  - 289
IS  - 8
SP  - 881
EP  - 888
PB  - Springer
CY  - New York
ER  -