Origins of saccharide-dependent hydration at aluminate, silicate, and aluminosilicate surfaces

Abstract

Sugar molecules adsorbed at hydrated inorganic oxide surfaces occur ubiquitously in nature and in technologically important materials and processes, including marine biomineralization, cement hydration, corrosion inhibition, bioadhesion, and bone resorption. Among these examples, surprisingly diverse hydration behaviors are observed for oxides in the presence of saccharides with closely related compositions and structures. Glucose, sucrose, and maltodextrin, for example, exhibit significant differences in their adsorption selectivities and alkaline reaction properties on hydrating aluminate, silicate, and aluminosilicate surfaces that are shown to be due to the molecular architectures of the saccharides. Solid-state 1 H, 13 C, 29 Si, and 27 Al nuclear magnetic resonance (NMR) spectroscopy measurements, including at very high magnetic fields (19 T), distinguish and quantify the different molecular species, their chemical transformations, and their site-specific adsorption on different aluminate and silicate moieties. Two-dimensional NMR results establish nonselective adsorption of glucose degradation products containing carboxylic acids on both hydrated silicates and aluminates. In contrast, sucrose adsorbs intact at hydrated silicate sites and selectively at anhydrous, but not hydrated, aluminate moieties. Quantitative surface force measurements establish that sucrose adsorbs strongly as multilayers on hydrated aluminosilicate surfaces. The molecular structures and physicochemical properties of the saccharides and their degradation species correlate well with their adsorption behaviors. The results explain the dramatically different effects that small amounts of different types of sugars have on the rates at which aluminate, silicate, and aluminosilicate species hydrate, with important implications for diverse materials and applications. S accharide molecules and their interactions with inorganic oxide surfaces play crucial roles in a variety of natural and synthetic processes, including biomineralization, biomolecule synthesis, bone resorption, heterogeneous catalysis, corrosion inhibition, and cement hydration. For example, mono-and oligosaccharides are thought to control the morphologies and structures of carbonate skeletons in marine organisms through sitespecific binding to the mineral phases (1, 2). Interactions of simple organic molecules with aluminosilicate surfaces and exchangeable cations in clays have been hypothesized to be key factors in abiotic syntheses of organic molecules (3). For example, sugar-silicate complexes have been shown to stabilize the abiotic formation of biologically important sugars, such as ribose (4). Similar interactions are thought to promote the adhesion of marine organisms at hydrated inorganic surfaces (5). Biofuels can be produced when polysaccharides are converted to monosaccharides and lower molecular weight alkenes at aluminosilicate zeolite surfaces by heterogeneous reactions in the presence of water (6). Saccharides have also been found to inhibit the corrosion of me...

Reactions and Surface Interactions of Saccharides in Cement Slurries

“…These results are consistent with the early hydration kinetics of tricalcium silicate in the presence of saccharides, where organic species have been shown to delay the onset of C−S−H formation at both ambient and elevated temperatures. 10,15 Thus, after hydration for 4 h at 95°C, the addition of 1% glucose or sucrose bwoc almost completely inhibits the formation of calcium silicate hydrates in white Portland cement.…”

“…For example, by comparing the relative integrated 29 Si NMR signal intensities associated with nonhydrated Q 0 species found in diand tricalcium silicate and the Q 1 and Q 2 moieties associated with C−S−H, the extent of silicate hydration can be determined. 10 Such analyses of the solid-state 1D single-pulse 29 Si MAS spectra for white Portland cement hydrated (4 h, 95°C…”

“…23 Polysaccharides, such as dextrins, have been studied to lesser extents, 24 with hydration inhibition shown to vary with their molecular weights and structures. Recent measurements 10 have established that maltodextrin exhibits intermediate efficacy at inhibiting the hydration of individual cement components, compared to sucrose and glucose. Although it has been inferred that saccharides adsorb at heterogeneous cement particle surfaces, until now, no direct measurements or identification of specific molecular interactions between adsorbed organic species and the various nonhydrated or hydrated components in cements have been reported.…”

“…In part, this has been due to challenges associated with the molecular characterization of interactions between organic molecules and inorganic surfaces in heterogeneous fluid−particle mixtures of diverse components. Recently, using advanced techniques of solid-state 2D nuclear magnetic resonance (NMR) spectroscopy in combination with surface forces measurements, Smith et al 10 showed that the hydration behaviors of individual cement components, such as tricalcium aluminate and tricalcium silicate, in the presence of glucose, sucrose, or maltodextrin are correlated with the alkaline stabilities, adsorption selectivities, and binding strengths of different organic species. Important questions, however, remain regarding the interactions of different saccharide species in complicated solution−solid mixtures of aluminate and silicate components, such as those found in hydrating white Portland and gray oilwell cements.…”

A force field for tricalcium aluminate to characterize surface properties, initial hydration, and organically modified interfaces in atomic resolution

“…5,10 A wide array of characterization techniques has thus been applied to cement phases, for example, X-ray diffraction (XRD), small angle neutron scattering (SANS), in situ imaging by transmission electron microscopy (TEM), atomic force microscopy (AFM) and nanoindentation, zeta potential measurements, nuclear magnetic resonance spectroscopy (NMR), infrared (IR), and Raman spectroscopy. [11][12][13][14][15][16][17][18] In addition, models and simulations have been developed to enhance understanding and materials design. 8,10,[19][20][21][22][23][24][25][26][27][28][29][30] Such approaches include electronic structure calculations, molecular dynamics, Monte Carlo, and continuum methods, as well as multi-scale combinations of methods.…”