Lub luag haujlwm tseem ceeb ntawm optical brighteners stems los ntawm lawv cov qauv tsim qauv molecular. Cov kev teeb tsa molecular ntawm cov tebchaw no zoo sib xws rau lawv cov cwj pwm kho qhov muag thiab kev siv tau zoo. Kev nkag siab tob txog lawv cov yam ntxwv ntawm cov txheej txheem yuav pab kom nkag siab cov kev cai ntawm kev ua kom pom kev ua tau zoo hauv cov xwm txheej sib txawv.
Optical brightener molecules feem ntau muaj peb ntu: ib qho kev sib txuas uas muaj ntxhiab, cov pab pawg hloov pauv, thiab txuas txuas txuas txuas txuas. Lub aromatic conjugated system yog lub hauv paus ntawm fluorescence tiam -ib nruam π-electron cloud forms delocalized orbitals. Thaum lub molecule absorbs ultraviolet lub teeb, cov electrons zoo siab rau lub zog siab, thiab thaum de-excitation, lawv tso xiav -violet pom lub teeb. Cov txheej txheem no tso siab rau qhov rigidity thiab planarity ntawm lub conjugated system kom ntseeg tau tias lub zog hloov pauv tau zoo. Cov pob txha pob txha muaj xws li benzene rings, naphthalene rings, stilbene, los yog coumarin lug. Ntawm cov no, lub conjugation ntev ntawm polycyclic aromatic hydrocarbons ncaj qha cuam tshuam rau fluorescence wavelength thiab siv: luv conjugated systems emit xiav lub teeb, thaum lub sij hawm ntev conjugated systems yog biased rau violet lub teeb. Los ntawm kev kho tus naj npawb ntawm cov rings thiab txoj kev sib txuas, spectral defects ntawm lub hom phiaj cov khoom tuaj yeem ua tau raws li qhov tseeb.
Cov pab pawg hloov pauv ua haujlwm ob lub hom phiaj: ua ntej, lawv tswj cov solubility thiab compatibility ntawm molecules. Piv txwv li, qhia cov pab pawg sulfonic acid (-SO₃H) thiab carboxyl pawg (-COOH) txhim kho cov dej solubility, ua rau lawv haum rau cov dej hauv dej; ntev -chain alkyl pawg lossis polyoxyethylene ether chains txhim kho kev sib cais hauv cov xov xwm tsis muaj polar. Qhov thib ob, lawv cuam tshuam fluorescence quantum yield los ntawm cov teebmeem hluav taws xob-electron- pab pawg pub dawb (xws li -NH₂, -OCH₃) ua kom cov electron ceev ntawm cov kab ke sib txuas, txhim kho UV nqus; electron-cov pab pawg rho tawm (xws li -NO₂, -CN) tuaj yeem tua cov fluorescence, yuav tsum tau ceev faj kom tsis txhob ua haujlwm poob.
Cov txheej txheem yooj yooj yim ntawm kev sib txuas bridging bonds yog qhov tseem ceeb sib npaug. Cov qauv nruj nrog ib daim ntawv cog lus (xws li ethylene ob daim ntawv cog lus hauv stilbene) tuaj yeem txhim kho lub dav hlau conjugated, txo lub zog dissipation los ntawm kev sib hloov intramolecular; thaum hloov pauv cov ntawv cog lus (xws li ether bonds thiab amide bonds) tuaj yeem txhim kho qhov hloov pauv ntawm cov molecules hauv cov matrices sib txawv thiab txo qhov kev pheej hmoo ntawm crystallization. Qee qhov siab -kev ua tau zoo optical brighteners ntiav cyclic bridging bonds (xws li triazole rings thiab oxadiazole rings) txhawm rau txhawm rau cuam tshuam kev sib xyaw ua ke los ntawm steric hindrance, tsis txhob muaj fluorescence quenching ntawm ntau heev concentrations.
Kev tsim qauv zoo ntawm cov qauv molecular kuj yuav tsum xav txog kev ruaj ntseg thiab kev hloov pauv ib puag ncig. Piv txwv li, kev qhia txog fluorine atoms tuaj yeem txhim kho lub lightfastness ntawm molecules thiab txo UV-induced degradation; tsim loj- pawg sab nraud tuaj yeem txo cov neeg tsiv teb tsaws chaw, ua tau raws li cov kev cai nruj ntawm cov khoom noj khoom haus thiab lwm yam kev thov. Kev tshawb fawb tam sim no tab tom tshawb nrhiav heteroatom doping (xws li boron thiab phosphorus) thiab stereoisomerization kom kov yeej cov kev ua tau zoo ntawm cov qauv qub.
Yog li, cov qauv molecular ntawm optical brighteners yog cov khoom siv dav dav ntawm kev ua haujlwm kho qhov muag, kev sib raug zoo ntawm lub cev, thiab kev ruaj ntseg ib puag ncig. Hauv -kev tsom xam qhov tob ntawm lawv cov qauv- kev sib raug zoo ntawm kev ua haujlwm yuav txuas ntxiv tsav kev tsim kho tshiab hauv kev tsim qauv ntawm kev ua haujlwm- taw qhia cov molecules, muab cov kev daws teeb meem zoo dua rau cov ntawv hla - kev lag luam.