Effect of Nonsolvent on the Formation of Polymer Nanomaterials in the Nanopores of Anodic Aluminum Oxide Templates

Abstract

We study the effect of nonsolvent on the formation of polymer nanomaterials in the nanopores of porous templates. Water (nonsolvent) is added into a poly (methyl methacrylate) (PMMA) solution in dimethylformamide (DMF) confined in the nanopores of an anodic aluminum oxide (AAO) template. Water forms a wetting layer on the pore wall and causes the PMMA solution to be isolated in the center of the nanopore, resulting in the formation of PMMA nanospheres or nanorods after the solvent is evaporated. The formation of the polymer nanomaterials induced by nonsolvent is found to be driven by the Rayleigh-instability-type transformation. Without adding the nonsolvent, PMMA chains precipitate on the walls of the nanopores after the solvent is evaporated, and PMMA nanotubes are obtained.

Wettability and Applications of Nanochannels

“…Moreover, the selective P2VP swelling in the PS‐ b ‐P2VP nanospheres caused internal structural reconstruction to form mesoporous nanospheres, which could be used as catalyst nanocontainers. Another Rayleigh instability‐based work was reported by Chen and co‐workers, studying the water effect on the polymeric nanomaterials formation in the internal nanochannels of AAO templates . Water was added into a dimethylformamide solution of PMMA confined within the nanochannels of the AAO template, which formed a wetting layer on the AAO channel wall and confined the PMMA solution in the center of the nanochannel.…”

“…Jin and co‐workers also reported utilizing AAO membrane with cylindrical nanochannels as template to prepare poly(styrene‐ b ‐2‐vinylpyridine) nanomaterials with various morphologies composed of nanotubes, nanorods, and nanospheres . Chen and co‐workers further studied the water effect on the PMMA nanomaterials formation in the nanochannels of the AAO template, indicating polymeric nanospheres or nanorods were formed with adding water to the polymeric solution, and polymeric nanotubes were obtained without adding water . PS‐ b ‐PDMS were also fabricated by Chen et al confined in the AAO nanochannels, and by regulation the weight ratios of PS, diverse morphologies of PS‐ b ‐PDMS nanomaterials were formed, containing nanorods, concentric lamellar, multihelical and spherical‐like morphology .…”

Fabrication of Multicomponent Polymer Nanostructures Containing PMMA Shells and Encapsulated PS Nanospheres in the Nanopores of Anodic Aluminum Oxide Templates

“…Therefore, the PS solution is isolated in the center of the nanopores. The cylindrical PS solution then undulates and becomes spherical solution domains to reduce the interfacial areas between PS solution and acetic acid . The transformation process is similar to the Rayleigh‐instability‐type transformation, which is driven by the reduction of the surface areas or the interfacial areas .…”

Ordered Organic Nanostructures Fabricated from Anodic Alumina Oxide Templates for Organic Bulk‐Heterojunction Photovoltaics

“…Therefore, nanoporous AAO templates with self‐organized hexagonal arrays of uniform parallel nanochannels have been intensively utilized as a popular template system for fabricating various functional polymer nanostructures. By infiltrating the polymers into nanopores, unusual 1D nanoscale structures with novel morphology, specific orientation, reduced crystallinity, enhanced mobility, gradient distributed composition, gradient distributed crystallites, and high thermal conductivity were produced in nanopores of AAO templates.…”