Preparation Of ZnS Quantum Dots/Biopolymer Nanocomposites Based On In Situ Method

Biopolymers have drawn much attention owing to their attractive properties,such as low cost,environmentally friendly preparation,and good biocompatibility.Biopolymers are promising for applications in biomedical materials,packaging materials,food materials,and energy materials.Recently,the combined materials of nanomaterials and biopolymers have gained increased attention in the development of advanced nanocomposite material.This work investigated the preparation of ZnS quantum dots(QDs)/biopolymer(e.g.alginate,carboxymethyl cellulose)nanocomposites by the simple and novel in situ method.Moreover,the properties and applications of the QDs/biopolymer nanocomposites were studied and evaluated.Initially,on the base of the electrode simultaneously undergoes anodic electrochemical oxidation and generates metal ions in situ,and then the alginate molecules in the deposition solution are able to bind to metal ions,thereby forming ionically crosslinked alginate gel.a simple and environment-friendly method was presented to prepare ZnS QDs/alginate film via in situ coordinated electrodeposition method by making use of alginate as the stabilizer for ZnS QDs.The resulting QDs/alginate film is homogeneous which shows clear fluorescence.TEM images demonstrate that the QDs average size is around 3.0 nm.Thereby,the result QDs/alignate film has a huge potentail application in fluorescence bioimaging,biosensor and photocatalytic degradation.Furthermore,based on the coordination of alginate to the metal ions,a simple,environment-friendly and drop method was presented to generate ZnS QDs/alginate nanocomposite beads with alginate working as stabilizer.Druing in situ synthesis QDs,the resulting gel beads not only act as the reaction support for the in situ preparation of QDs,but they also can serve as the stabilizer to prevent QD aggregation.The method has many benefits such as the simple preparation,the environmentally friendly process,the mild conditions,and the easy post-treatment for the beads.The resulting QDs/alginate beads are homogeneous and stable gel spheres which show clear fluorescence,and the QDs average size is about 2.4 nm.Potentially,the QDs/alginate beads can be utilized for fluorescence bioimaging,as well as fluorescence detection toward metal ions.Besides,in this work,the ZnS quantum dots/carboxymethyl cellulose capsules were prepared by simple method by making use of carboxymethyl cellulose as the stabilizing agents.The resulting QDs/carboxymethyl cellulose capsules show a clear fluorescence under 302 nm of UV light and the QDs average size is about 3.0 nm.The method has many benefits such as the simple preparation,the environmentally friendly process,the mild conditions,and the easy post-treatment for the capsules,which are promising for appealing applications in fluorescence bioimaging,control reease and so on.In summary,concise and novel methods to directly produce QDs/biopolymer nanocomposite were developed.The methods have many benefits such as the simple preparation,the environmentally friendly process,the mild conditions,and the easy post-treatment.The resulting QDs/biopolymer nanocomposites clear fluorescence,which are promising for appealing applications in fluorescence bioimaging,control reease,photocatalytic degradation and biosensor.In addition,this work also provide important theoretical and practical basis for in situ construction QDs/biopolymer nanocomposite.