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Synthetic polyester elastomeric constructs have become increasingly important for a range of healthcare applications, due to tunable soft elastic properties that mimic those of human tissues. A number of these constructs require intricate mechanic design to achieve a tunable material with controllable curing. Here, we present the synthesis and characterization of poly(itaconate-co-citrateco-octanediol) (PICO), which exhibits tunable formation of elastomeric networks through radical crosslinking of itaconate in the polymer backbone of viscous polyester gels. Through variation of reaction times and monomer molar composition, we were able to generate materials with modulation of a wide range of elasticity (36-1476 kPa), indicating the tunability of materials to specific elastomeric constructs. This correlated with measured rapid and controllable gelation times. As a proof-of-principle, we developed scaffold support for cardiac tissue patches, which presented visible tissue organization and viability with appropriate elastomeric support from PICO materials. These formulations present potential application in a range of healthcare applications with requirement for elastomeric support with controllable, rapid gelation under mild conditions.

Understanding the surface properties and interactions of nonspherical particles is of both fundamental and practical importance in the rheology of complex fluids in various engineering applications. In this work, natural chrysotile, a phyllosilicate composed of 1:1 stacked silica and brucite layers which coil into cylindrical structure, was chosen as a model rod-shaped particle. The interactions of chrysotile brucite-like basal or bilayered edge planes and a silicon nitride tip were measured using an atomic force microscope (AFM). The force-distance profiles were fitted using the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, which demonstrates anisotropic and pH-dependent surface charge properties of brucite-like basal plane and bilayered edge surface. The points of zero charge (PZC) of the basal and edge planes were estimated to be around pH 10-11 and 6-7, respectively. Rheology measurements of 7 vol % chrysotile (with an aspect ratio of 14.5) in 10 mM NaCl solution showed pH-dependent yield stress with a local maximum around pH 7-9, which falls between the two PZC values of the edge and basal planes of the rod particles. On the basis of the surface potentials of the edge and basal planes obtained from AFM measurements, theoretical analysis of the surface interactions of edge-edge, basal-edge, and basal-basal planes of the chrysotile rods suggests the yield stress maximum observed could be mainly attributed to the basal-edge attractions. Our results indicate that the anisotropic surface properties (e.g., charges) of chrysotile rods play an important role in the particle-particle interaction and rheological behavior, which also provides insight into the basic understanding of the colloidal interactions and rheology of nonspherical particles.

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