Dense, hydrated polymer-ceramic composites are central to applications including additive manufacturing, cementitious infrastructure, and biomimetic mineralized materials. In these systems, polymers regulate flow behavior, transport phenomena, nucleation kinetics, and microstructural evolution across multiple length scales. However, establishing predictive relationships between polymer architecture, evolving structure, and material performance remains challenging because these processes occur within highly concentrated, hydrated environments. This dissertation employs multiscale characterization including rheometry, small-angle neutron and x-ray scattering (SANS/SAXS), x-ray diffraction (XRD), and cryogenic scanning electron microscopy (CryoSEM) to probe polymer-mediated structural evolution in hydrated composite systems.

 

The first component examines concentrated alumina suspensions (ϕ=0.55) containing non-adsorbing poly(vinyl pyrrolidone) (PVP), representative of highly loaded industrial ceramic formulations. Systematic variation of polymer molecular weight and concentration demonstrates that non-adsorbing polymers can tune suspension rheology. Increasing polymer loading and molecular weight increased the dynamic yield stress of the material, emhanced shear thinning, and delayed the onset of discontinuous shear thickening. Rheological measurements coupled with insights from SANS reveal how polymer and particle length scales govern suspension flow behavior.

 

The second component investigates alkoxysilane-functionalized hydrogels designed to actively participate in cement hydration and curing. CryoSEM demonstrates that silane functionalization promotes nucleation-dominated calcium silicate hydrate (C-S-H) growth, refines cement microstructure, and reduced hydrogel-induced macrovoid formation through increased integration with the cement matrix.

 

The final component examines confined C-S-H mineralization within polyacrylamide hydrogels using a one-dimensional double diffusion platform. Mineralization across multiple crosslink densities was characterized using macro photography, CryoSEM, SAXS, and XRD. Increasing crosslink density progressively constrained mesoscale mineral structure. Furthermore, mineralized regions retained the as-synthesized polymer swelling state throughout the 48-hour reaction despite substantial differences in the equilibrium swelling capacity of the unmineralized gels – indicating that mineralization arrests network expansion.

 

Collectively, these studies establish mechanistic relationships linking polymer structure to suspension rheology, hydrate nucleation, and mineralization. More broadly, this work demonstrates how multiscale characterization can be used to predict and control structure evolution in hydrated polymer-ceramic composites.