The Preparation Of Helical Polydiacetylene Triggered By Visible/Near Infrared Circularly Polarized Light

Chirality(Kheir),was defined as chirality by the scientist of Lord Kelvin in the 1983.As one of the basic characters of nature,it often appared in the various interdisciplines and was used to describe the phenomenon that the object can not overlap with its mirror image.If the relationship between the object and counterpart was the same relation as left and right hand,with the same chemical elements composition and can not overlap together,we described the object was chiral,and defined them as enantiomer,isomer for short.Chiral compounds were ubiquitous in the area of Chemistry,Biomedical,Material science and their interdisciplines,such as D/L type amino acids,glucose,DNA.Introducting the chirality in to the polymers to synthesize the helical chiral polymers,it can generated the polyers several special characters:(1)Chiral sensors and chiral recognition;(2)Chiral amplication and switch;(3)enantioselective photo-polymerization;(4)The modulation of CPF.Due to the fact that chirality was ubiquitous ranging from astronomy to geography,from chemistry to biology,and usually acted in a specific form in nature,However,Circularly polarized light(CPL),which could be observed in star-forming regions of the Orion constellation,has long been proposed as one of the tools to synthesize helical structure conjugated polymers which behaved optical rotation,and modulate the asymmetric catalysis and cis-trans isomerism of photo-stimuli-resopnsive materials.Polydiacetylene is a particularly interesting photo-stimuli-responsive material,due to its fortunate conjunction of environmentally sensitive optical characteristics and easy formation in self-assembled systems,several morphologies have been fabricated such as vesicles,liposomes,tubes,LB films,casting films,nanocomposites or fibres,in the applications for sensors,Logic operations,imaging,displays.Introducting the novel electro-optical properties into PDA materials is of great value in the application of biological sensor,chiral medicine synthesize and the essence of life evolution.As we known,The solid-state polymerization of DA monomers is often required with UV,high-energy y-irradiation or heating treatment,however,High-energy y-irradiation and thermal treatment are not suitable for device fabrication because they may cause damage to integrated materials.Therefore,several methods have been made by doping cyanine dyes,TiO2 or Ruthenium complex to the system to sensitize solid-state polymerization of diacetylene in the visible light region.However,to the best of our knowledge,the mechanism of polymerization is not clear,and attempts to synthesize helical PDA with CPVL have not been described to date.Based on the previous works,In this paper,the main contents of my works and results are as follows:1.The 10,12-Pentacosadiynoic acid(PCDA)films with optimized concentration loading of([Ru(dupphen)3]Cl2)were prepared by spin-coating methods.Upon irradiation with 532 nm circularly polarized light(CPVL),the enantio-selective polymerization of DA units was realized,and the helical structure of PDA was prepared in the visible light region successfully.Moreover,the helical PDA could also achieved by the combination of upon irradiation with the combined light(the CPVL and unpolarized 254nm UV light,simultaneously)without any dopants,By changing the polarization of 532 nm,the screw direction of helical PDA could also be totally controlled by the handedness of incident 532 nm CPL.Furthermore,we also studied the polymerization rate constants,g values,and kinetics curves at 650 nm for PDA.Finally,we get the conclusion that the interaction between the CPVL and the PDA oligomer played a dominant role,and could effectively direct the handedness of the final obtained PDA chain.In this case,the radicals was assumed to be the asymmetric carbenes specious rather than diradicals.2.With the chemical reaction method,we designed novel benzaldehyde-substitute diacetylene(BSDA)monomer.As reported previously,benzaldehyde units are known as photo-active unit and would generated the benzoyl and the a-hydroxybenzyl intermediate radicals upon irradiation with visible light,which could be utilized to initiate the polymerization of the neighboring DA units in the visible light region.In order to polymerize the DA monomers in the near infrared(NIR)light region,we synthesize the Lanthanide-doped upconversion nanoparticles(UCNPs)and prepared the BSDA/UCNPs hybrd film.Lanthanide-doped upconversion nanoparticles(UCNPs)can convert low-energy near infrared(NIR)light into high-energy UV and visible light via the absorption of two or multi low-energy photons.It should be note here that the polarization state of upconvention emission(UCL)greatly depend on the aggregation state of NaYF4 UCNPs in the hybrid films.For pure NaYF4 UCNPs powder or the sample with highly aggregated NaYF4 UCNPs,the UCL exhibited polarization isotropy upon irradiation with 980 nm linearly polarized or circularly polarized light.Only single or few-particles aggregates of NaYF4 UCNPs,the polarization of UCL followed the same polarization direction as that of the excitation 980 nm light.Therefore,it is anticipated that the generated UCL could also be utilized to trigger the enantio-selective polymerization of the BSDA/NaYF4 UCNPs(w/w,100/1)hybrid film.The rate constant of polymeriation k1 was 1.3 × 10-3 s-1,a little lower than that upon irradiationwith circularly polarized UV or visible light.Therefore,the inherent chirality of 980 nm CPL could be transferred to the UCL during the upconversion process,making it possible for realizing NIR-CPL triggered enantioselective photo-polymerization of BSDA monomer by incorporating the NaYF4 UCNPs as the antenna species.3.Based on the previous work,we synthesized the amino subsituted DA monomers and prepared into vesicles.Then the vesicle was fabricated in to 1D PDA microtube through the hierarchiral self-assembly method in the presence of metal irons(Zn2+ or Pb2+).The microtube was about 1-3 ?m in outer diameter,the tube wall was about to be 0.5?m.Upon irradiation with 254nm light,the PDA microtube could be polymerized in to blue phase.With the treatment of acid or heating,the microtube exhibits an intense color change as well as fluorescence change.Interestingly,we demonstrate that the microtube could serve as an active optical material.Upon irridiation with 532nm light in the body of microtube,the locally excited FL could propagate along the microtube,and a tip emission of the microtube.2,4,6-Trinitrophenol(TNP),one kind of explosive in dye and food industries.Owing to the biotoxicity and explosibility,the rapid and selective detection of TNP has becoming a major significant topic.Due to the characters that the amino group on the surface of the mrcrotube,the TNP can ionization of proton form hydroxyl group.Then the electron transfer from the red phase PDA microtube to the TNP molecule,as well as quenching the fluorescence emission,and inhibit the waveguide process.However,the fluorescence of above microtube could also recover with the treatment of ethanol,which can removal the TNP form PDA microtube.Therefore,we developed the PDA microtube which serve as optical waveguide and was utlized as a highly reproducible and selective sensor for TNP,with a lower LOD(0.11ppm)than the maximun acceptable level in drinking water(0.5mg/ml).4.The fabrication of one-dimensional(ID)nano/micrometer-sized optoelectronic devices which have the potential applications in the areas such as information storage,processing and optoelectronic modulations,has drawed great attention to the scientists.the preparation and multiconfigurable logic gate operation in the one-dimensional waveguide devices is of great significance.We prepared the PDA microtube through the hierarchiral self-assembly method,and modified the tube with the electrical-responsive viologen units(VFPDA)by the same methods as the spiropyran functionalized polydiacetylene(SFPDA)microtubes.The fluorescence of red phase VFPDA microtube could be quenched uppon the applying volet of-1.5V,which is attributed to the fluorescence resonance energy transfer(FRET)mechanism between the viologen(Mv+)and PDA matrix,and the fluorescence could also recovered with the applying volet of 1.5V(no FRET between Mv2+ and VFPDA microtube).Therefore,we can modulate the waveguide with electricity.It should be note here that the arrangement between PDA chains in the viologen-microtube and the axis of tube was about 60°,uppon irridiation with 532 nm linear polarized light(LPL)was 60°,a strong tip emission in the tube,if the LPL was 150°,a weaker tip emission will be observed.So another modulation menthod is polarized light.The third factor is heating treatment which is attribute to the blue-to-red transition characters.Based on the above three factors,we constructed several logic gates(AND,INHIBIT,NOR,INHIBIT-INHIBIT,AND-INHIBIT)by the different stimus(heating treatment,electrical stimuli and LPL)in the viologen modified PDA microtube successfully,which may pave the way for the design smart devices for further develoment.