Cov dej ua solubility ntawm hloov kho cellulose ether yog cuam tshuam los ntawm qhov kub. Feem ntau hais lus, feem ntau cov neeg ua haujlwm cellulose yog soluble hauv dej ntawm tsawg kub. Thaum qhov kub nce, lawv solubility maj mam ua neeg pluag thiab thaum kawg ua insoluble. Txo cov kev daws qhov kub thiab txias (LCST: qis dua kev daws teeb meem rau kev hloov pauv ntawm qhov kub thiab txias rau qhov kub thiab txias, cellulose ethere yog insoluble hauv dej.
Cov cua sov ntawm aqueous methyCellulose kev daws teeb meem tau kawm thiab kev hloov pauv ntawm kev hloov pauv ntawm solubility tau piav qhia. Raws li tau hais los saum toj no, thaum kev daws teeb meem ntawm methylcellulose yog nyob rau ntawm qhov kub tsawg, macromolecules tau ncig los ntawm dej lwg me me los ua tus qauv tawb. Cov cua sov tau thov los ntawm qhov kub thiab txias yuav tawg ntawm cov pab pawg me me, thiab cov me me lub pob zeb me me, thiab cov me me lub pob zeb me me, uas ua rau nws npaj tau thiab kawm cov Hydrophobic Association ntawm hydroxypropyf methylcellose thermally induced hydrogel. Yog tias cov methyl pawg ntawm tib txoj saw hlau yog hydrophobically sib khi, kev sib txuam no yuav ua rau tag nrho cov me me tshwm sim. Txawm li cas los xij, qhov nce hauv qhov kub yuav ua rau pom cov lus tsa suab, kev sib txuam hydecuic yuav tsis ruaj khov, thiab cov molecular yuav hloov pauv ntawm lub xeev coiled mus rau lub xeev ntev. Nyob rau lub sijhawm no, kev sib cuam tshuam hydrophobic ntawm cov lwg me me pib thawj. Thaum qhov ntsuas kub maj mam nce, ntau dua thiab ntau dua thiab ntau dua cellule molecules tau sib sau ua ke los ntawm hydrophobic sib txuas lus los ua ib qho hydrophobic aggregate. Nrog rau kev nce ntxiv nyob rau hauv qhov kub ntxiv, thaum kawg txhua tus hydrophobic koom nrog mus txog qhov siab tshaj plaws, nce tus naj npawb thiab loj ntawm hydrophobic aggregates. Thaum lub sijhawm cov txheej txheem no, methylcellulose tau zuj zus ntawm insoluble thiab thaum kawg ua kom tiav insoluble hauv dej. Thaum qhov kub nce mus rau qhov chaw uas muaj peb-seem network network yog tsim ntawm macromolecules, nws zoo li tsim cov gel macroscopically.
Jun Gao thiab George Haidear thiab cov txiaj ntsig kub kawm txog kev daws teeb meem ntawm hydroxy ntawm hydroxyprropyl cellulose yog li 410c. Ntawm qhov ntsuas kub tsawg dua 390c, lub xeev molroxyprropyl ntawm cov molecules faib ntawm molecules faib, thiab tsis muaj kev sib sau ua ke ntawm macromolecules. Thaum qhov kub tau nce mus rau 390c, kev sib cuam tshuam hydrophobic nyob nruab nrab ntawm cov molecular charts ua kom muaj zog dua, thiab cov dej solubility, thiab cov dej solubility ntawm polymer ua tsis zoo. Txawm li cas los xij, ntawm qhov kub no, tsuas yog ib feem me me ntawm hydroxypropyl cellulose muaj qee qhov kev sib tw me me, thaum feem ntau ntawm cov lwg me me tseem nyob hauv lub xeev cov saw hlau sib txuas. Thaum qhov kub nce rau 400c, ntau macromolecules koom nrog kev tsim cov kev sib sau ua ke, thiab lub solubility ua rau muaj kev phem zuj zus thiab lub sijhawm no, qee cov lwg me ntsis tseem nyob hauv lub xeev ntawm ib lub saw hlau. Thaum qhov kub ntawm 410C-440C, vim muaj cov txiaj ntsig hydrophibic nyhuv ntau dua, ntau dua molecules sib sau ua ke los ua kom loj dua. Nce nce ua loj dua thiab denser. Qhov tsim ntawm cov hydrophobic aggregates ua rau kev tsim cov cheeb tsam ntawm kev ua siab thiab qis polymer hauv kev daws teeb meem, ib qho kev sib cais micreen sib cais.
Nws yuav tsum tau taw qhia tias Nanoparticle Aggregates yog nyob rau hauv lub xeev kinetically ruaj khov, tsis yog lub xeev thermodynamically tsis ruaj khov. Qhov no yog vim hais tias thawj tus qauv txheej txheem tau raug puas tsuaj, tseem muaj cov pab pawg hydrophilic xws li methyl thiab hydroxypropyl los ntawm kev sib txuas ntawm. Lub Nanoparticle argregates mus txog ib qho kev sib npaug sib luag thiab ruaj khov nyob rau hauv txoj kev sib koom tes ntawm ob qho teebmeem.
Ib qho ntxiv, txoj kev tshawb fawb kuj pom tias cov cua sov tus nqi tseem muaj kev cuam tshuam rau kev tsim cov khoom sib sau ua ke. Ntawm tus nqi cua sov nrawm dua, kev sib sau ua ke ntawm cov molecular chains sai dua, thiab qhov loj me ntawm cov nanoparticles tsim me; Thiab thaum tus nqi cua sov qeeb qeeb, Macromolecules muaj ntau txoj hauv kev los tsim loj dua-qhov loj me Nanoparticible.
Lub Sijhawm Post: Apr-16-202