Well-defined carbohydrate-based polymers in calcium carbonate crystallization: Influence of stereochemistry in the polymer side chain on polymorphism and morphology

Abstract In this work we demonstrate the remarkable phase control on the crystallization of calcium carbonate by the stereochemistry of carbohydrate-based polymers. The polymers (poly(2-(2,3,4,6-tetra-O-acetyl-β- d -glucosyloxy)ethyl methacrylate) and poly(2-(2,3,4,6-tetra-O-acetyl-β- d -galactosyloxy)ethyl methacrylate)) have been synthesized from the respective glucose or galactose containing monomers (3 step synthesis) by RAFT polymerization leading to well-defined carbohydrate-based polymers with number averages of the molecular weights (Mw) of 10,000–18,000 g/mol and a dispersities (Đ) from 1.1 to 1.2. For the deprotected polymers we found differences in the phase selection of calcium …

Ab Initio Structure Determination of Vaterite by Automated Electron Diffraction

tion that is fundamental for understanding material properties. Still, a number of compounds have eluded such kinds of analysis because they are nanocrystalline, highly disordered, with strong pseudosymmetries or available only in small amounts in polyphasic or polymorphic systems. These materials are crystallographically intractable with conventional Xray or synchrotron radiation diffraction techniques. Single nanoparticles can be visualized by high-resolution transmission electron microscopy (HR-TEM) up to sub�ngstrom resolution, [2] but obtaining 3D information is still a difficult task, especially for highly beam-sensitive materials and crystal structures with long cell parameters. Elec…

PAA-PAMPS Copolymers as an Efficient Tool to Control CaCO3 Scale Formation

Scale formation, the deposition of certain minerals such as CaCO3, MgCO3, and CaSO4 center dot 2H(2)O in industrial facilities and household devices, leads to reduced efficiency or severe damage. Therefore, incrustation is a major problem in everyday life. In recent years, double hydrophilic block copolymers (DHBCs) have been the focus of interest in academia with regard to their antiscaling potential. In this work, we synthesized well-defined blocklike PAA-PAMPS copolymers consisting of acrylic acid (AA) and 2-acrylamido-2-methyl-propane sulfonate (AMPS) units in a one-step reaction by RAFT polymerization. The derived copolymers had dispersities of 1.3 and below. The copolymers have then b…

Phase selection of calcium carbonate through the chirality of adsorbed amino acids.

Inside Cover: Phase Selection of Calcium Carbonate through the Chirality of Adsorbed Amino Acids (Angew. Chem. Int. Ed. 29/2007)

Ab-initio-Strukturbestimmung von Vaterit mit automatischer Beugungstomographie

Innentitelbild: Phasenselektion von Calciumcarbonat durch die Chiralität adsorbierter Aminosäuren (Angew. Chem. 29/2007)

Interaction of Alkaline Metal Cations with Oxidic Surfaces: Effect on the Morphology of SnO2 Nanoparticles

Reaction pathways to SnO(2) nanomaterials through the hydrolysis of hydrated tin tetrachloride precursors were investigated. The products were prepared solvothermally starting from hydrated tin tetrachloride and various (e.g., alkali) hydroxides. The influence of the precursor base on the final morphology of the nanomaterials was studied. X-ray powder diffraction (XRD) data indicated the formation of rutile-type SnO(2). Transmission electron microscopy (TEM) studies revealed different morphologies that were formed with different precursor base cations. Data from molecular dynamics (MD) simulations provide theoretical evidence that the adsorption of the cations of the precursor base to the f…

Phasenselektion von Calciumcarbonat durch die Chiralität adsorbierter Aminosäuren

Reply to “Mirror Symmetry Breaking” of the Centrosymmetric CaCO3 Crystals with Amino Acids

CCDC 1429729: Experimental Crystal Structure Determination

Related Article: Enrico Mugnaioli, Iryna Andrusenko, Timo Schüler, Niklas Loges, Robert E. Dinnebier, Martin Panthöfer, Wolfgang Tremel, Ute Kolb|2012|Angew.Chem.,Int.Ed.|51|7041|doi:10.1002/anie.201200845

CCDC 1429728: Experimental Crystal Structure Determination

Related Article: Enrico Mugnaioli, Iryna Andrusenko, Timo Schüler, Niklas Loges, Robert E. Dinnebier, Martin Panthöfer, Wolfgang Tremel, Ute Kolb|2012|Angew.Chem.,Int.Ed.|51|7041|doi:10.1002/anie.201200845