The spherical micelle and vesicle composed of [PW12O40](3-) and poly(styrene-b-4-vinylpyridinium methyl iodide) are regarded as a model system to study spherical polymer brushes (SPBs) in solvents of various quality. The pure repulsions occur for the brush chains in the chloroform solution and chloroform/methanol mixture with a methanol volume ratio of 9.1%, where the grafted polystyrene chains have a relatively extended conformation. Further increase in the methanol concentrations leads to the presence of the intra/inter-brush van der Waals attractions. Transmission electron microscopy studies show that there is a coexistence of isolated and oligomeric SPBs and multi-SPB aggregates (MSAs) with the methanol content from 17% to 23%. Only MSAs are detected with the increasing methanol content. Both the corona and core shrink significantly in the isolated and oligomeric SPBs and MSAs. The full interpenetration of the grafted chains is observed between the cores in the oligomeric SPBs and MSAs.

The controllable interactions of a spherical polymer brush modeled by a poly(styrene-b-4-vinylpyridinium methyl iodide)-polyoxometalate composite micelle, SVP-6, with a polyoxometalate-based supramolecular star polymer, PSP-4, in solvents of variable quality allow us to tune their self-assembly behaviors from self-recognition to supramolecular recognition. In the former case, isolated, contractive spheres together with a few vesicles formed by PSP-4 coexist with multimicelle aggregates formed by SVP-6, whereas SVP-6 is hosted inside the vesicle of PSP-4 in the latter case. This work represents an important step toward the development and understanding of programmable self-assembly of brushlike polymers into complex materials.

Polyoxometalate-based supramolecular star polymers, where an anionic polyoxometalate is closely encapsulated by a hydrophobic shell of cation terminated polystyrenes, are conceptually regarded as a model of star polymers to study their intra-and interstar interactions and self-assembled behaviors in solvents of variable quality. These model stars can self-assemble to form unilamellar freestanding sheets in the toluene/methanol mixture solvent with a methanol volume ratio of 50%. An increase in the methanol content to 75% or 80% results in a coexistence of free-standing sheets with vesicles, where several intermediates are captured for the morphological evolution from sheet to vesicle. With further increasing methanol content to 90%, pure vesicle phases form with unilamellar or oligolamellar features. All these aggregates are packed by the totally hydrophobic starlike polymers, where the core−shell structures are retained. This is distinctly different from the bilayered nanostructures formed by amphiphiles such as surfactants and block copolymers in selective solvents.

The development of a water-developable negative photoresist from b-CD using an acid-catalyzed chemical amplification method is investigated here. Tertiary butoxyl protected b-cyclodextrin (t-BOC-CD) is also synthesized and used to prepare a positive photoresist. Glutaraldehyde is added as a crosslinking agent for both positive and negative photoresists. Deprotection of t-BOC-CD is accelerated by a photo-induced acid. In the presence of glutaraldehyde and acid, both the deprotected t-BOC-CD and b-cyclodextrin are crosslinked. The introduction of a t-butoxyl group into the b-CD molecule and the addition of glutaraldehyde into the b-CD molecules are both found to decrease the crystallinity of the molecules, improving the resist film properties. The etching resistance of both positive and negative photoresist films is improved by the crosslinking method.

No abstract