Morphological Control of Calcium Oxalate Dihydrate by a Double-Hydrophilic Block Copolymer

Abstract

The crystallization of calcium oxalate in aqueous solutions of a double-hydrophilic block copolymer poly(ethyleneglycol)-block-poly(methacrylic acid) (PEG-b-PMAA) has been investigated, focusing on morphological control of the calcium oxalate dihydrate (COD) crystals. It has been shown that with increasing polymer concentration, the morphology of the obtained COD crystals gradually changed from tetragonal bipyramids dominated by the {101} faces to rodlike tetragonal prisms dominated by the {100} faces, which is a morphology adopted by some plant COD crystals but not obtained in vitro previously. The concentration of calcium oxalate and the [Ca2+]/[C2O4 2-] ratio were also found to show considerable effects on the morphology of the obtained COD crystals. Seed growth experiments further demonstrated the drastic effect of the polymer on the COD crystal morphology. This effect was preliminarily discussed in terms of possible structural correlation between the short PMAA chain of the polymer and the COD {100} planes.

Polymer‐Induced Alignment of dl‐Alanine Nanocrystals to Crystalline Mesostructures

“…The strong morphology-directing effect of the block copolymer with its chiral sticker groups is clear, and nicely supports the DHBC concept, as previously applied to inorganic compounds, such as CaCO 3 , [27,[33][34][35][36][37][38] Ca x (PO 4 ) y (OH) z , [30] BaSO 4 , [39][40][41][42][43][44] BaCrO 4 , [45,46] ZnO, [47][48][49][50] CaC 2 O 4 *2H 2 O, [51] CdWO4, [52] and lanthanides [53] or Au. [54] Chiral aspects during the crystallization have been examined mainly by the Lahav group.…”

Effect of Diazotated Sulphonated Polystyrene Films on the Calcium Oxalate Crystallization

“…In Figure 6, it is possible to observe diffraction peaks that are attributable to both COD as COM crystals. However, more intense peaks, detected at 2θ, such as 15 • , 25 • , 30 • and 31 • , correspond to crystal planes {1 0 1}, {2 1 1}, {2 0 2} and {0 2 0} of COM crystals respectively, which confirm what is observed by the above analysis [43,[71][72][73][74]. In general, the use of this kind of functionalized DSPF film as a solid organic template could contribute to understanding the mechanisms underlying the formation of biologically important minerals, such as pathological urinary crystal forms, and it is kinetic on surface deposition.…”

Untitled

“…1e). This is because small caltrops contain mainly steroidal glycosides, steroidal saponins 16,17 , linoleic acid, oleic acid, and stearic acid 18 . Hence, these functional groups of protein and acid could transform the structure of COM to COD.…”