Aggregation Behavior of Cyclodextrin‐Based [3]Rotaxanes

The aggregation of a cyclodextrin (CD)-based [3]rotaxane has been observed and analyzed in detail for the first time in this work. Although the hexagonal packing aggregation of CD-based polyrotaxane is a well known phenomenon, corresponding studies in terms of rotaxanes without any polymer structure have not been conducted so far, probably owing to the difficulty of the molecular design. We synthesized a series of [3]rotaxane species by using a urea-end-capping method and evaluated their aggregation behavior by XRD and SEM measurements. [3]Rotaxane species containing native CD rings showed clear signals assigned to the hexagonal packing by XRD measurement as did polyrotaxane; this proved their aggregation capability. Because the corresponding per-acetylated derivatives did not show this aggregation behavior, the driving force of this aggregation was suggested to be hydrogen bond formation among CD units. The effect of axle end structures and partial acetylation of CDs were also studied

A Bioinspired Hierarchical Underwater Superoleophobic Surface with Reversible pH Response

The development of oil-repellent surfaces in liquid environments has received considerable attention because of the urgent demand for antifouling coatings in marine industry. Inspired by the unique nanostructure surface of filefish scale, hierarchical films that consist of poly(pentafluorophenyl acrylate) free standing micropillars grafted with pH responsive poly(methacrylic acid) nanobrushes are fabricated by anodic aluminum oxide templating method combined with a subsequent post-polymerization modification strategy. The obtained films exhibit constantly underwater superoleophobicity, furthermore, a pH sensitive functionality, which enables reversible switching between low and high oil adhesion as a result of the adjustable oil sliding angle. This particular study provides a very mild method for the facile fabrication of bioinspired nanostructures with excellent oil-repellent performance and switchable oil-adhesion properties, thus paving the way toward novel functional materials with smart structures for promising applications, such as smart microfluidics, controllable bioadhesion, and intelligent materials for oil removal treatment and marine antifouling

A CO2_{2}-gated anodic aluminum oxide based nanocomposite membrane for de-emulsification

A carbon-dioxide-responsive organic–inorganic nanocomposite membrane based on a through-hole anodic aluminum oxide (AAO) template was constructed. The composite was prepared via a surface-initiated reversible addition–fragmentation chain-transfer (SI-RAFT) polymerization strategy to achieve the grafting of poly(methyl methacrylate-co-2-(diethylamino)ethyl methacrylate) brushes on the AAO membrane. The grafted polymer chain length could be controlled based on the feed ratio between the free chain transfer agent (CTA) and reactive monomer, e.g., methyl methacrylate and 2-(diethylamino)ethyl methacrylate, resulting in a membrane that features adjustable water permeability. Importantly, the membrane pore size and surface wettability could be switched from hydrophobic to hydrophilic upon the introduction of carbon dioxide and nitrogen gases. This allowed for the nanocomposite membrane to be utilized for controlled water flux and oil/water emulsion separation. The simple fabrication methodology as well as sustainable gaseous stimulus will be useful for the construction of future smart membranes

Synthesis and Post-Polymerization Modification of Poly(N-(4-Vinylphenyl)Sulfonamide)s

Herein, a straightforward synthesis of a novel class of polymers, that is, poly(N-(4-vinylphenyl)sulfonamide)s, and their monomers is reported. A set of monomers with varying electron densities, fine-tuned by different substituents on the aromatic sulfonamide moiety, is polymerized by free radical polymerization featuring low molar masses (2300 ≤ M$_{n}$ ≤ 3200 g mol$^{-1}$) and low dispersities (1.15 ≤ Đ ≤ 1.47). Further, the post-polymerization modification of the obtained polymers via aza-Michael addition with electron-deficient alkenes is demonstrated using organic superbases as catalysts, paving the way toward the facile synthesis of novel polymeric protected β-amino acid derivatives

Polymeric Janus nanorods via anodic aluminum oxide templating

We report a novel method for the fabrication of polymeric Janus nanorods via sequential polymerization from anodic aluminum oxide (AAO) templates. Dual compositions can be incorporated into individual nanorods and endow versatile potential applications. This fabrication strategy paves the way for constructing multifunctional nanostructures and brings together different materials in a single entity

Decarboxylation of Poly[ N ‐(acryloyloxy)phthalimide] as a Versatile Tool for Postpolymerization Modification

Herein the decarboxylation of poly[N-(acryloyloxy)phthalimide] (PAP) for the synthesis of functionalized polymers is reported. PAP homopolymer and block copolymers are used as precursor polymers for the straightforward functionalization via decarboxylation and subsequent Michael-type addition or nitroxide radical coupling (NRC)