Proton-Activated Room-Temperature Phosphorescence Of PMMA And PLA Based On Sulfur Derivatives

Room temperature phosphorescence(RTP)materials play an important role in biological tissue engineering,bio-sensor,and data encryption and so on.The most advanced organic RTP materials are organometallic compounds containing precious metals.However,due to the problems of limited resources,high price,low toxicity,and narrow scope of molecular design,researchers are more interested in the research of non-metallic organic RTP light emitters.Because of oxygen,humidity and thermal movement can cause phosphorescence inactivation.Thus the crystal structure of organic small molecules can successfully achieve RTP,nevertheless after the crystal structure is destroyed,RTP will be greatly weakened or even disappear,so the small molecule RTP material is limited in the actual application process.The polymer’s large molecular weight and long-chain structure determine that it can have high rigidity and effectively block oxygen and humidity,thus promote the generation of RTP.In addition to small molecules with crystal structures,organic polymers are also an ideal way to achieve RTP.Polymer-based RTP materials have excellent properties such as good flexibility,thermal stability,low cost,and easy processing,and have broad application prospects in practical applications.Stimulus-responsive RTP polymers have attracted the attention of researchers in recent years.At present,RTP materials respond to acids are mainly concentrated in small molecule crystals,while there are fewer RTP polymers respond to acids.Therefore,it is urgent to find an RTP polymer with excellent performance,simple production operation and responsiveness to acid.1.This paper designed and synthesized three sulfur derivatives 2-(4-(benzothiazol-2-yl)-2-methoxyphenoxy)eth-l-ol(BOOH),2-(4-(Benzothiazol-2-yl)phenoxy)eth-1-ol(BOH)and 2-((4-(benzothiazol-2-yl)phenyl)thio)eth-1-ol(BSH),to verify the molecular structure by nuclear magnetic spectroscopy;the steady-state emission spectrum shows that the sulfur derivatives emit only weak blue fluorescence at room temperature,and after induction by protonic acid(hydrochloric acid),emit yellow fluorescence at room temperature;cyclic voltammetry test results show that charge transfer occurs within the protonated molecule.Since the RTP of the thiosulfin derivative is quenched at room temperature,it needs to be inserted into the polymer material to avoid RTP inactivation.2.Blend BOOH,BOH and BSH with polymethyl methacrylate(PMMA)to obtain PMMA/sulfurine derivative blend.After induction with protonic acid(benzenesulfonic acid),protonated PMMA/BOOHH+,PMMA/BOHH+and PMMA/BSHH+emit RTP under vacuum.When the molar ratio of PMMA/sulfurine derivative blend to benzene-sulfonic acid is 1:8,the steady-state emission spectrum shows that the maximum phosphorescence emission wavelength of the PMMA/BOOHH+blend is 564 nm,and the orange-red RTP is emitted;PMMA/BOHH+The phosphorescence maximum emission wavelength of the blend is 526 nm,which emits yellow RTP;the phosphorescence maximum emission wavelength of the PMMA/BSHH+blend is 562 nm,which emits orange-red RTP.3.BOOH,BOH and BSH were respectively polymerized with polylactide(PLA)to obtain PLA-sulfurine derivative.The results of nuclear magnetic spectrum and gel permeation chromatography showed that PLA-sulfurine derivative with high molecular weight was synthesized.After being induced by protonic acid(benzenesulfonic acid,oxalic acid and p-toluenesulfonic acid monohydrate),the steady-state emission spectrum shows that PLA-BOOHH+and PLA-BSHH+will have orange-red RTP,the maximum emission wavelength of PLA-BOOHH+is 558nm,and the phosphorescence life-time is 108.19ms.PLA-BSHH+has a maximum emission wavelength of 556nm and a phosphorescence lifetime of 16.10ms.The PLA-BOHH+emits yellow-green RTP,the maximum emission wavelength of PLA-BOHH+is 528nm,and the phosphorescence lifetime is 105.39ms.In addition to benzenesulfonic acid,oxalic acid and p-toluenesulfonic acid monohydrate can also induce PLA-thiosulfure derivatives to emit RTP,but benzenesulfonic acid induces PLA to produce RTP with a longer lifetime,with a maximum lifetime of 108.19ms.