Topology sorting: Separating linear/star polymer blend components by imbibition in nanopores

Area of Science:

• Polymer Science
• Materials Science
• Nanotechnology

Background:

• Understanding polymer behavior in confined spaces is crucial for nanotechnology.
• Polymer blends exhibit complex dynamics influenced by architecture and confinement.

Purpose of the Study:

• To investigate the imbibition and adsorption kinetics of linear and star cis-1,4-polyisoprene blends in nanoporous anodic aluminum oxide (AAO).
• To explore the influence of polymer architecture and viscosity on confinement dynamics.
• To establish relationships between imbibition and adsorption timescales.

Main Methods:

• In situ nanodielectric spectroscopy was employed to monitor polymer chain dynamics.
• Symmetric linear/star cis-1,4-polyisoprene blends with varying molar masses were used.
• Analysis focused on the longest chain modes and dielectric strength evolution.

Main Results:

• Imbibition kinetics differed between linear and star polymers, with lower viscosity components penetrating first.
• Adsorption kinetics were generally slower in blends compared to homopolymers, except when linear chains acted as diluents for stars, inducing topology sorting.
• A universal relationship (τads ∼ 10 × tpeak) was identified, linking adsorption time (τads) to pore filling time (tpeak).

Conclusions:

• Imbibition timescale is a key factor governing polymer adsorption kinetics in nanopores.
• Polymer architecture significantly impacts confinement behavior and self-assembly.
• The findings enable prediction of adsorption times for various polymer architectures based on imbibition dynamics.