title: Introducing porosity into polyimide nanoparticles.
abstract: Novel porous polyimides (PIs) having diameters of several hundred nanometers have been fabricated successfully from precursor poly(amic acid) (PAA) derivatives with poly(acrylic acid) (PAS) as the porogen, using a reprecipitation method and subsequent imidization. The superficial high porosity with deep pores was introduced when using a more compatible combination of PAA and the porogen, i.e., PI (BPDA-PDA) and PAS rather than PI (10FEDA-4FMPD and PAS); the pore sizes ranged from 20 to 100 nm. The resulting porous PI nanoparticles had thermally stabilities (determined from their 5% weight loss temperatures at 400 degrees C) similar to those of corresponding PI nanoparticles lacking porous structures. Microphase separation within the PAA nanoparticles after reprecipitation induced the porous surface structure, the properties of which were influenced by the molecular weight of PAS and the chemical structure of PAA. These unique porous PI nanoparticles have great potential for application as low-k materials in next-generation technologies.
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Aobaku, Sendai 980-8577, Japan.
authors.forename: Gufan
authors.initials: G
authors.lastname: Zhao
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ishizaka
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kasai
authors.forename: Hachiro
authors.initials: H
authors.lastname: Nakanishi
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Oikawa