Novel copolymers based on acrylamide （AM） and complex pseudorotaxane monomer N＇-（3-vinylbenzyl）-l,4- diaminobutane dihydrochloride with cucurbit[6]uril （CB[6]） （3VBCB） were prepared via free-radical polymerization in aqueous solution, and characterized by XH-NMR, FT-IR, elemental analysis and static light scattering. The compositions of the copolymers （PAM3VBCB） with pseudorotaxane units were determined by 1H-NMR and elemental analysis. Thermal properties of the copolymers were studied by TGA, and the effects of the copolymer concentration and pH on the average hydrodynamic radius （Rh） of the copolymer molecules were studied by dynamic light scattering （DLS）. The experiment data show that CB[6] beads are localized on 1,4-diaminobutane units in side chains of the copolymers. TGA results show that thermal stability of the copolymer increases with increasing the content of pseudorotaxane unit because of the enhanced rigidity and the bulky steric hindrance of 3VBCB in side chains of PAM3VBCB. DLS data show that the average hydrodynamic radius of copolymer molecules increases with the increase in the copolymer concentration, and both the pH and electrical conductivity of PAM3VBCB solutions demonstrate an acute change with addition of NaOH because of CB[6] dethreading from the side chains of PAM3VBCB. CB[6] threading and dethreading of PAM3VBCB could be controlled by addition of BaC12 and Na2SO4.
Novel dual-responsive superhydrophobic hybrid materials, ZnO/SAMs （self-assembled monolayers） of ionic liquids （ILs） with different counter-anions （I^-, BF4^-, PF6^- and Tf2N^-）, were synthesized and characterized. ZnO nanoparticles were first deposited on glass surfaces to produce roughness. Next, SAMs of fluorinated-alkyl-3-（3-triethoxysilylpropyl）-4,5-dihydro-imidazoliumiodide （abb. [C8Ftespim]I） were grafted onto these surfaces via -Si-O- covalent bonds using self-assembly technique. The I- ion could be subsequently exchanged with BF4, PF6-or Tf2N- through a simple aqueous anion-exchange reaction. The ZnO/ILs hybrid layers were characterized by atomic-force microscopy （AFM）, scanning-electron microscopy （SEM） and X-ray photoelectron spectroscopy （XPS）. Their wettability was estimated through the measurements of static and dynamic contact angles （CAs）. Compared to corresponding films of ZnO/[CsFtespim]I with CAs 140.7° ±2.0°, films of ZnO/[CsFtespim]PF6 and ZnO/[CsFtespim]Tf2N showed CAs with 154.0° ± 2.0° and 152.0° ± 2.0°, respectively that remained for a long time. This result suggests that anion-exchange can afford superhydrophobic materials. In addition, the wettability of ZnO/[CsFtespim]X hybrid layers can be reversibly switched by altering ultraviolet （UV） irradiation and dark storage, which shows a photo-induced reversible switch of wettability. The synergistic action of ZnO nanoparticles and SAMs of ILs produced light-anion dual-responsive superhydrophobic materials with ideal stability.
A fluorescent pyrene derivate, N-allyl-l-pyrenemethylammonium hydrochloride （APA＊）, was reported to form a stable host-guest complex with cucurbit[8]uril （CB[8]）, and this property can be utilized to determinate the purity of CB[8] via emission titration. Moreover, the 1：1 complex of APA and CB[8] can further bind methyl viologen （MV^2＋）, which is the main ingredient of a widely used herbicide, providing a good method to detect MV^2＋, especially at low concentrations.
We report layer-by-layer （LbL） assembly of TiO2 and H4SiW12O40 （SiW12） multilayer film on silicon wafers and glass slides for photocatalytic degradation of methyl orange （MO）. The photocatalytic efficiency of the obtained multilayer film increases along with the decrease of pH and salt concentration of the incubation solution. The results show that MO can be almost re- moved in pH 2.0 solution without salt addition in the first 60 min incubation when MO concentration is lower than 15 mg/L. Different salts show an apparent inhibitory effect on photocatalytic degradation of MO with the order of ZnC12〉KCI〉 NaC1〉LiCI. The TiO2/SiW12 multilayer film maintains photocatalytic activity even after five degradation cycles. The reaction of MO photodegradation accords with an apparent first-order dynamics.
