Self-stabilized thermothickening colloids

Inventors

Shull, Kenneth R. • Chen, Yaoyao

Assignees

Northwestern University

Abstract

A thermothickening fluid is provided which comprises a liquid phase; a first polymer comprising functional groups and having a room temperature solubility in the liquid phase; and a second, different polymer comprising functional groups and having a room temperature solubility in the liquid phase, wherein functional groups on the first polymer are capable of associating with functional groups on the second polymer to form complexes, and the room temperature solubility of the first polymer is greater than the room temperature solubility of the second polymer. The fluid is a colloid at room temperature, a solution at an elevated temperature, and exhibits a thermothickening/thinning transition viscosity value at a thermo-thickening/thinning transition temperature between room temperature and the elevated temperature.

Core Innovation

The invention relates to a thermothickening fluid that includes a liquid phase with a first polymer and a second, different polymer. The first polymer has functional groups and a room temperature solubility in the liquid phase, and the second polymer also has functional groups and a room temperature solubility in the liquid phase, where the first polymer’s room temperature solubility is greater than the second polymer’s room temperature solubility. Functional groups on the first polymer associate with functional groups on the second polymer to form complexes.

The fluid is a colloid at room temperature and becomes a solution at an elevated temperature. It exhibits a thermothickening/thermothinning transition with a thermothickening/thinning transition viscosity value at a thermo-thickening/thinning transition temperature between room temperature and the elevated temperature. The approach uses complementary functional-group association together with different room-temperature solubilities to create the temperature-driven viscosity maximum.

The disclosed design includes charged functional groups that provide self-stabilization of the colloidal state. The design rationale includes polymer identity, a solubility parameter threshold concept, and polymer loading and stoichiometry to define the transition behavior. Characterization is described using turbidity, dynamic light scattering, and rheology.

Claims Coverage

The document includes one independent claim. It covers a thermothickening fluid defined by two different associating polymers with different room-temperature solubilities, complex formation by associating functional groups, and a temperature-dependent colloid-to-solution behavior that produces a thermothickening/thermothinning viscosity transition at an intermediate transition temperature.

Overall, the claim coverage is centered on a thermothickening fluid that relies on complexes formed between functional groups on two different polymers with different room-temperature solubilities, producing a colloid-to-solution transition and a thermothickening/thermothinning viscosity transition at an intermediate temperature between room temperature and the elevated temperature.

Stated Advantages

Documented Applications

No documented applications found