The aqueous non-ionic surfactant decaethylene glycol hexadecyl ether (
C(16)EO(10)), in the presence of CaCl2, forms novel ''calcitropic'' la
mellar liquid-crystal phases. Thin films of these materials display no
table structure sensitivity to the hydrophobicity or hydrophilicity of
the underlying support. A structure-bonding model of these materials
is based upon Ca2+-crown ether-like coordination to the decaethylene g
lycol head group of one or two of the surfactant molecules. Ca2+ bindi
ng of two surfactant head groups, makes possible cis- and trans-confor
mations for the alkyl tails, resulting in normal and inverted structur
es with preferences for hydrophilic and hydrophobic surfaces, respecti
vely. The extent of Ca2+ ion clustering in the head group determines t
he geometrical packing requirements of the surfactant and the overall
dimensions of the resulting lamellar liquid-crystal phases. The effect
of various phosphate reagents (H3PO4, KH2PO4, K3PO4) On these ''calci
tropic'' liquid-crystal phases has also been investigated. The conditi
ons that favor the deposition of different calcium phosphate solid pha
ses from these ''calcitropic'' lamellar precursors have been investiga
ted, with a view to their possible use as ''controlled release biomate
rials'' for supplying thin-film and nanocrystalline forms of calcium p
hosphate for bone restoration, replacement, and augmentation applicati
ons. The nontoxic, biocompatible, biodegradable, and inexpensive natur
e of oligoethylene glycol alkyl ethers is a distinctive advantage for
these kinds of endeavors.