Preparation Of Photonic Composite Films Based On Structure-directing Nanocrystalline Cellulose And Study On Optical Selective Recognition

Photonic crystals are extensively existing in natural organisms,which present coloring phenomenon due to their ordered-orientation structure.Inspired by this structural color,people began to create humanly constructed photonic crystals,using them in optical coating,anti-counterfeit tag and physicochemical sensor.Ordered colloid arrays and nematic liquid crystals are familiar assembly of photonic crystal.Among them,the photonic crystal materials constructed by nematic liquid crystals have the advantage of uniform color and easy of fabrication.Nanocrystalline crystalline as one of typical nematic liquid crystals,have been widespread use in the design of chemical sensor because of the advantages of abundant source and green initiative.These sensors are achievable for the optical recognition of society-relevant species,which their recognition process and recognition performance are respectively portable and easy to observe.However,the synthetic chemical sensors for recognition based on structural directing nanocrystalline crystalline showed the limitation of low selectivity.Therefore,the article would bring fluorescent technique into the system of nanocrystalline crystalline to fabricate an optical selective recognition of photonic crystal material,and then used in rapid fluorescence identification for aromatic compounds.In order to improve the specific recognition of photonic crystal chemical sensor,I brought molecular imprinting technique into the system of nanocrystalline crystalline to fabricate the chemical sensor for sulfa pollutants of optical selective naked-eye recognition.The detail of each experiments as follow:?1?Grafting Eu?III?-based complex into chiral nematic mesoporous silica formed by structural directing nanocrystalline crystalline,a dual recognized film showed both fluorescence and photonic crystal properties,which was used in rapid selective fluorescent recognition for nitrobenzene.The results of characterization showed:the film material was chiral nematic mesoporous structure,which its surface area and pore size were300 m² g^-1 and 7.0 nm respectively.The fluorescence analysis showed the mesoporous silica film was in response to strong fluorescent signals in the586 nm and 612 nm,which can be used in detecting 10?M nitrobenzene,and its fluorescence quenching within 5 minutes reached equilibrium with quenching efficiency of 50%.Meanwhile,the fluorescent silica films upon exposure to nitrobenzene vapor also showed fluorescence quenching.?2?A copolymerization of sulfanilamide-imprinted phenolic resin into nanocrystalline crystalline prepared the chiral nematic photonic crystal material.After the removal of templates,obtained imprinted film materials were used for optical selective recognition of sulfanilamide.A series of characterizations showed:imprinted composite film possessed layered porous structure and good hydrophilicity,which its static contact angle was63±2.3°.Besides the film showed tailorable flexibility and chiral nematic characteristic of strong birefringence and fingerprint textures.The results of naked-eye recognition analysis showed,the color of imprinted films changed from red to yellow with an increase of the sulfanilamide concentration,and a shift maximum of 27.6 nm was observed.Meanwhile,photonic imprinted film showed the naked-eye selective recognition for sulfonamides from antibiotics.?3?Combining sulfamethoxazole-imprinted phenol-formaldehyde-urea resin polymer with structural directing nanocrystalline cellulose,an optical composite film was fabricated.After the removal of templates,the obtained structural color chemical sensor was used for optical selective recognition of sulfamethoxazole in water.The results indicated:imprinted mesoporous film possessed chiral nematic structure and its surface area and pore size were 254 m²g^-1and 7.0 nm respectively.The optical recognition analysis showed,the analyte-fasten region of the film showed a yellow response and the response time was within 30 minutes,subsequently no further color changes can be observed.When use 1.0 mg mL^-1sulfamethoxazole solution to immerse imprinted film,a shift maximum of42 nm was recorded by UV-Vis-NIR spectrophotometer.Comparative experiments confirmed the imprinted films showed excellent optical selective recognition ability for sulfamethoxazole in water.