Nanoporous Polymer Films from Immiscible Polymer Blends: Pore Size and Composition Dependence

Abstract

Nanoporous polymer films have been prepared using immiscible blends of polyetherimide (PEI) and poly(caprolactone diol) (PCLD). The films were prepared by spin-coating from a common solvent -dichloromethane (DCM). To create the nanoporous films, PCLD was removed by immersing the films in acetone, which dissolves PCLD only. Field emission scanning electron microscopy was used to study the porous structure. The pore structure of the films was affected by many factors such as composition of the blend, molecular weight, and various processing parameters. The formation of nanometer size pores was mainly due to the fast phase separation process during spin-coating. The pore size and pore size distribution was found to depend on the blend composition.

Nanomembrane Materials Based on Polymer Blends

“…There are many factors that would influence these factors, such as polymer blend composition, molecular weight of the blend components, thermal history, and processing conditions. In order to study the effects of these on the final pore structures, a careful characterization of the pores is necessary [99]. Previous techniques to control the size of nanoporous membranes involve coating pores with polymers [109] or metal [110].…”

“…One other possible approach is to create a two-phase mixture and remove the minority phase through physical or chemical means [99]. Porous polymer films represent a distinct, yet important, subclass of responsive multi-functional materials [100,101].…”