Design And Performance Research Of A New Material Based On Sodium Alginate Ultra-long-life Room Temperature Phosphorescence

In recent years,organic persistent room temperature phosphorescent(p-RTP)materials have attracted wide attention from researchers.In the past,afterglow materials were limited to inorganic complexes or rare earth complexes,which had the disadvantages of high cost,high biological toxicity,and large environmental pollution.The development of organic afterglow materials solved these shortcomings.As a natural product,sodium alginate has a wide range of sources and good biocompatibility.Therefore,sodium alginate-based materials have good application prospects.However,at present,the development of organic p-RTP materials based on sodium alginate is less,and the development of organic p-RTP materials of biological macromolecules including other polysaccharides is also relatively scarce.Therefore,according to the structural characteristics of SA and the characteristics of organic p-RTP materials,this article will combine the two to develop ultra-long-life room temperature phosphorescent materials based on sodium alginate.Sodium alginate not only has a large number of hydrogen bonds but also a large number of ionic bond interactions.Therefore,we propose an ionization strategy to construct sodium alginate-based p-RTP materials,that is,make full use of SA ionic bond and hydrogen bond interactions with the ionized phosphorescent chromophore to inhibit the non-radiative transition of the phosphorescent chromophores to achieve high-efficiency p-RTP(the highest phosphorescence quantum efficiency is 25%,and the longest phosphorescence lifetime is 1481ms).In addition,by adjusting the number and relative position of the ionogens of phosphorescent chromophores,the aggregation of the phosphorescent chromophores can be tuned to change its phosphorescence.Through a simple ionization doping method,it can be prepared into an p-RTP film or used as an anti-counterfeiting ink.SA also has the characteristic of semi-rigid molecular chain structure.Based on this characteristic,this paper proposes the design concept of dual polymer for the development of p-RTP materials.The progress is to modify the phosphorescent chromophores to the SA backbone firstly,and then blend the SA derivatives with PVA.Compared with the traditional single polymer p-RTP material,the advantage of the preparation method of this dual polymer is that it has both a rigid chain and a flexible chain.The rigid chain mainly plays a role in tuning the aggregation of the phosphorescent chromophores,the flexible main chain is wrapped around the rigid chain to improve the overall conformational rigidity of the materials.The two complement each other,not just the linear superposition of the two polymers.Using this design concept,a series of p-RTP materials have been successfully developed(the afterglow color changes from yellow to green to blue over time,with the longest phosphorescent life reaching 2132ms).The design concept of this dual-polymer p-RTP can also be extended to other material systems.