| Smart materials, which are sensitive to external stimuli (electric field, magneticfield, light irradiation, pressure response, thermal treatment, pH, glucose concentration, redox response, gas stimulation, humidity), leading to the dynamic transformation of their physical structures or chemical properties, such as surface wetting properties, assembly and disassembly in supramolecular chemistry, swelling and shrinkage in materials science and drug controlled-release. Functionally synergetic systems, which are fabricated from two or more smart surfaces or materials to yield a complex function, have attracted wide attention. In order to farther promote the development of the concept about the functionally cooperating device and achieve the integration and coordination of a variety of intelligent materials. It has many important applications in nanoscience, microfluidic control and controlled oil-water separation fields.We have designed and developed three new preparation methods of nano smart devices, we have respectively used for the transportation of small molecules in oil/water/oil three-phase system, efficient directional removal of underwater oil spill by additional magnetic field and controlled continuous separation of oil/water/oil. The main works was as follows:(1) Fabrication of temperature responsive smart device and application in directional transportion. Based on porous nickel foam, we have fabricated temperature responsive functionally cooperating device by integrating Pt wire with H2O2responsive properties and a temperature-responsive PNIPAAm by SI-ATRP that displayed a diving-surfacing cycle in response to thermal treatment. When the temperature was changed from above the LCST to below the LCST, the temperature-responsive transformation from superhydrophobicity to superhydrophilicity occurred and caused the deice to dive. When the temperature was subsequently raised above the LCST and3ml hydrogen peroxide was added, the smart device re-floated on the water surface, because of the oxygen bubbles generated by the decomposition of hydrogen peroxide catalyzed with the platinum. Furthermore, the smart device was used to realize a directional delivery of lipophilic molecules between three phases by adjusting temperature and improved the application value of the smart devices.(2) Magnetically directed clean-up of underwater oil spills through a functionally integrated device. The device was fabricated by the facile electroless metal deposition method, self-assembled monolayer membrane technology and magnetically responsive materials. Guided by an external magnet, the device could directionally collect oil both underwater and on the water surface quickly and efficiently. We further studied the separating efficiency, which demonstrated a re-collecting efficiency as high as90%. This result has provided important data support for directional and efficient oil removal in underwater.(3) A pH-responsive smart surface for the continuous separation of oil/water/oil ternary mixtures. A smart device was fabricated through electroless metal deposition followed by surface modification with a mixed thiol containing carboxylic groups and methyl groups. This modification allowed the surface wettability to be switched from superhydrophobic to superhydrophilic in response to the pH of an aqueous solution. The surface wettability of the smart device was investigated both in air and underwater under alkaline conditions, whereby superhydrophobicity/superoleophilicity and superhydrophilic/superoleophobic properties were observed, respectively. By taking advantage of this pH-dependant wettability, the smart device was applied to oil/water separations both in air and underwater. Efficient separation and collection of the individual components of a complex oil/water/oil mixture was realized in a continuous process with no ex situ treatments. |
PDF Full Text Request