Nanomaterials tau dhau los ua qhov tseem ceeb ntawm kev tshawb fawb vim lawv cov khoom siv physicochemical tshwj xeeb; Txawm li cas los xij, nanoparticles yog qhov yooj yim rau agglomeration thaum npaj. Qhov no ua rau txo qis ntawm thaj chaw tshwj xeeb thiab tsis zoo dispersibility, ua rau muaj kev cuam tshuam loj heev hauv kev siv xws li catalysis thiab kev hnov qab. Cov txheej txheem ziab khaub ncaws-xws li qhov cub kom qhuav los yog rotary evaporation-feem ntau ua rau cov khoom sib xyaw ua ke ntau dua vim qhov kub thiab txias los yog capillary rog. Chav ntsuas ntsug khov- cov tshuab ziab khaub ncaws muab cov kev daws teeb meem zoo rau qhov kev sib tw no los ntawm kev siv qhov tshwj xeeb qis- qhov kub thiab txias, ib puag ncig lub tshuab nqus tsev.
Nanoparticle agglomeration thaum lub sij hawm ziab yog feem ntau yog tsav los ntawm cov dej choj quab yuam thiab lub zog nto. Raws li cov dej evaporates los ntawm kev ncua, ib qho roj av nkhaus - cov ntaub ntawv sib txuas ua kua, ua kom muaj zog capillary zog uas compress thiab khi cov khoom nyob ib sab. Nyob rau tib lub sijhawm, cov khoom uas tsis muaj kev tiv thaiv hnyav yuav sib sau ua ke kom txo qis lub zog ntawm lub cev, uas tau tsav los ntawm lawv lub zog siab. Cov txheej txheem thermal ziab khaub ncaws zoo li ua kom cov txheej txheem no ua kom nruj.
Vertical khov- tshuab ziab khaub ncaws inhibit agglomeration los ntawm peb - cov txheej txheem tseem ceeb:
Kev siv tshuab khov nrawm nrawm yog ua haujlwm thaum tus qauv ua ntej- kho. Cov kua nitrogen los yog cov cuab yeej cryogenic yog siv los ua kom cov nanoparticle ncua kev kawm ntawv hauv milliseconds, tsim cov dej khov me me. Qhov no vitrification-zoo li khov khov zoo immobilizes cov khoom, tiv thaiv kev hloov kho thiab sib sau ua ke los ntawm kev loj hlob thiab nthuav dav ntawm cov dej khov nab kuab.
Lub tshuab nqus tsev sublimation ziab theem yog qhov tseem ceeb. Nyob rau hauv lub siab tej yam kev mob nyob rau hauv lub triple point, ice crystals sublime ncaj qha mus rau hauv dej vapor. Vim tias cov khoom siv - mus rau - roj hloov pauv hla cov kua dej theem, capillary rog uas tshwm sim los ntawm cov kua- theem nro saum npoo raug tshem tawm. Kev tsim qauv ntsug ua kom zoo dua qhov kev teeb tsa ntawm qhov chaw txias txias thiab cov qauv chav, tsim kom muaj qhov ntsuas kub ntsug uas ua kom yooj yim rau kev tsiv teb tsaws ntawm cov dej vapor mus rau qhov txias txias, yog li txo qis hauv zos micro-ib puag ncig hloov pauv los ntawm vapor backflow.
Kev tswj qhov kub thiab txias gradient yog siv thaum lub sijhawm tom qab-kev kho mob. Ib qho ntau-theem cua sov profile yog siv rau qhov kawg ntawm cov txheej txheem ziab, tso cai rau cov qauv ntsuas kub kom maj mam nce ntawm -60℃mus rau chav tsev kub. Qhov kev kho cua sov no maj mam tshem tawm cov dej adsorbed, tiv thaiv cov khoom sib tsoo thiab cov agglomeration los ntawm thermal stress los ntawm qhov kub thiab txias tam sim ntawd. Thaum xaiv cov cuab yeej siv, peb qhov kev ntsuas yuav tsum tau ua tib zoo saib: qhov ntsuas kub ntawm qhov ntsuas kub yuav tsum ncav cuag qis dua -86℃kom ntseeg tau tias dej ntes tau zoo; lub tshuab nqus tsev yuav tsum muaj kev khiav hauj lwm siab qis dua 10 Pa; thiab cov qauv khib yuav tsum yog qhov zoo ntawm ntau txheej txhuas tais nrog thermal conductivity zoo heev. Cov txheej txheem ua haujlwm suav nrog: tswj qhov kev ncua kev kawm ntawm 0.5% thiab 2%; ntxiv 5% trehalose raws li ib tug cryoprotectant; thiab teeb tsa lub voj voog kom qhuav lub sijhawm ntawm 24 thiab 72 teev, nyob ntawm cov qauv tuab.
Cov thev naus laus zis no tau ua tiav rau kev npaj ntawm cerium oxide nanozymes. Cov kev sim sib piv tau pom tias cov qauv ua tiav los ntawm kev khov kho ntsug- ziab ua tiav BET thaj chaw tshwj xeeb ntawm 120 m² / g-ze li peb zaug ntawm qhov cub- cov qauv qhuav. Transmission electron microscopy (TEM) tau lees paub lub xeev monodisperse particle nrog qhov nruab nrab qhov nruab nrab ntawm qhov loj me ntawm 8 nm, thaum pawg tswj tau nthuav tawm qhov tseem ceeb agglomeration, nrog ntau qhov sib sau ntau tshaj 50 nm hauv qhov loj.
Los ntawm kev siv cov txheej txheem tswj lub cev, lub chaw soj nstuam ntsug khov- tshuab ziab khaub ncaws hauv paus tshem tawm cov xwm txheej uas ua rau muaj kev sib txuam hauv cov txheej txheem ziab khaub ncaws. Nws daim ntawv thov nyob rau hauv cov teb xws li nanodrug cab kuj thiab quantum dot synthesis yuav txuas ntxiv tsav kev loj hlob ntawm nanomaterials mus rau kev ua tau zoo thiab kev siv tau zoo. Kev paub meej meej khov kho- cov txheej txheem ziab yuav yog tus yuam sij rau kev kov yeej cov fwj hauv qhov loj - nplai ntau lawm ntawm nanomaterials.
