Functional Nacre-like Composites Based On Hyperbranched Poly (Aimdo Amine)

The natural nacre is of excellent properties, such as high strength and high toughness. These excellent properties come from the unqiue brick-and-mortar structure of nacre. Inspired by the natural nacre, many high-strength and high-toughness nacre-like composites have been fabricated. Furthermore, fluorescent and conductive nacre-like composites were fabricated by assembling functional structural materials and polymers, for example, the fluorescent layered double hydroxide or conductive graphene oxide nanosheets. However, there are only few reports on the multifunctional nacre-like composites.The fluorescent hyperbranched poly(amido amine) (HPAMAM) is a kind of polymer with a lots of amine and amide groups. It can form strong hydrogen bonds with nanoclay. Therefore, the HPAMAM is an ideal substrate polymer to fabricate fluorescent nacre-like composites. The HPAMAM can bind Cu2+ ions strongly. Moreover, the Cu2+ may introduce new functions to the fluorescent nacre-like composites assembled from HPAMAM and nanoclay. Because of the physical crosslinking effect of Cu2+ to the HPAMAM molecules, the mechanical strength of the nacre-like hybrid films could be greatly improved. Inherented from the Cu2+ ions, these composites also showed excellent anti-bacterial property. In the first part of this dissertation, we made full use of the structure features of HPAMAM and prepared a kind of nacre-like hybrid film with antibacterial, fluorescent property, and higher mechanical strength. This kind of hybrid films is of great potential to be applied widely in biological researches.HPAMAM has fluorescent property, in addition to the wide emission band. It is easy for the emission band of HPAMAM to overlap with that of the other fluorescent substances. Therefore, the high-efficient Frost resonance energy transfer may occure between the HPAMAM and the selected fluorescent substances. In the second part of this dissertation, we tried to elevate the luminescent intensity of HPAMAM first. After that, we introduced various types and amounts of fluorescence materials into the HPAMAM/nanoclay films. Multi-colour emission nacre-like composites were fabricated. When the HPAMAM was chosen as the fluorescence donor, and riboflavin (R):rhodamine B (RhB) as the fluorescence receptors and integrated them in approximate ratios, the obtained nacre-like composite could emit white colour under 365 nm UV irradiation. It was thought that this design could be good references to the research of multifunctional artificial nacre composites.In summary, we have obtained some interesting results in the research of functional nacre-like composites based on HPAMAM. Nevertheless, it is believed that there are more amounts of functional composites, which might be more interesting, based on the HPAMAM to be explored and developed.