Tsim cov yeeb yaj kiab zaj dab neeg

1. Coagulation yog qhov tshwm sim ntawm qhov kev sib txuas adsorption ntawm qhov matrix molecules thiab cov evaporating atoms

Hauv lub tshuab nqus tsev, thaum lub zog ntawm cov cua evaporating ntov rau saum npoo ntawm lub substrate, lub zog hloov pauv nrog cov substrate molecule yog mob los ntawm lub zog ntawm lub substrate, thiab lub cev adsorption thiab chemisorption tshwm sim ntawm cov evaporating atom thiab substrate molecule. Lub cev adsorption yog ob qho Vander Waals rog sib ze ntawm txhua qhov ntawm cov khoom siv molecules, thiab cov chemical adsorption yog cov tshuaj sib kis ntawm cov atoms. Tsis tag nrho cov evaporation atoms tau tawm nrog cov tshuaj substrate molecules, qee qhov atoms kom feem ntau ntawm lawv lub zog, thiab kev sib tsoo tshwm sim tom qab kev xav, txawm tias cov evaporated atoms adsorbed nws tseem tuaj yeem raug pauv mus rau hauv cov nqes sab hauv los yog los ntawm desorption thiab tawm ntawm saum npoo ntawm substrate. Tsis tas li ntawd, nyob rau saum npoo ntawm lub substrate, nws muaj ib qho kev sib txuas ntawm cov kab mob evaporated thiab tib lub hom atoms adsorbed rau saum npoo ntawm cov substrate. Cov txheej txheem ntawm evaporating atoms adsorbed los ntawm substrate yog hu ua agglomeration.

Qhov piv ntawm cov condensed atom rau cov xwm txheej atom yog hu ua coacervation coefficient ntawm evaporation atom. Vim muaj qhov sib txawv ntawm qhov atoms, lub agglomeration coefficient ntawm tib hom hom evaporation rau ntau hom substrates sib txawv.

Txhua cov evaporated atom muaj txawv txav ntawm cov yeeb yaj kiab uas ua rau nyias qhov sib txawv thiab qhov kub ntawm lub substrate yog qis tshaj qhov tseem kub ntawm qhov yeeb yaj kiab, nws yuav tsum condensed. Qhov tshwm sim no tuaj yeem raug txhais tau tias: Thaum lub ntsuas kub ntawm lub substrate siab dhau lawm, cov evaporating atoms impinging nyob rau hauv cov npoo sab substrate yog los yog thim rov qab los sis ua kom zoo dua. Nyob rau hauv zaj duab xis txoj kev ua yeeb yaj kiab (kev ua yeeb yaj kiab), txawm hais tias qhov kub ntawm lub substrate tshaj qhov kub hnyiab, tus yeeb yaj kiab tuaj yeem loj hlob tuaj, thiab nws lub xeev yuav hloov. Nyob rau theem pib ntawm cov yeeb yaj duab uas ua tiav, zaj duab xis nyob hauv amorphous lub cev los yog vitreous lub cev, nrog kev nce siab, zaj duab xis maj maj mus rau txoj kev hloov mus, yog tias qhov no tseem muaj ntxiv mus, nws yuav hloov mus rau qhov kawg, thaum kawg hauv cov duab xis.

2. Tsim cov txheej txheem ntawm nyias zaj duab xis

Thaum pib ua kom tiav, lub pob zeb substrate ua rau lub cev tsis sib haum ntawm cov atoms, qhov sib cuam tshuam ntawm cov atoms ntawm cov evaporation sib sau ua ke nyob rau hauv ib co nuclei uas loj hlob, tsiv teb tsaws, kev sib sau, tsim ntawm ntau lub me Islands tuaj (cov ntoo loj loj nuclei sib sau ua ke) , hla hiav txwv ntawm cov pob zeb no loj hlob zoo ib yam li ib leeg, txuas nrog rau cov kob loj loj. Nrog cov deposition, qhov siab ntawm cov Islands tuaj thiab cov kob me me tuaj zuj zus tuaj, thiab thaum kawg lub network qauv nrog ditches yog tsim los ntawm tag nrho lub hauv paus sab. Qhov tshwm sim ntawm kev sib evaporation, cov evaporation atoms yog ib qho tseem ceeb nucleated thiab cov kob nyob rau hauv lub trenches, thiab nws thiaj li cov tiav ditches maj sau. Thaum lub kwj deg thiab qhov hauv qhov chaw ntawm lub hauv paus puv lawm, cov cua hauv tsev no tseem ua kom txhua tus yeeb yam ntawm cov qauv no.

Hauv lub tshuab electron microscope, nws yuav pom tau tias cov pa thermal evaporation films yog txhua yam cylindrical lug. Cov kev taw qhia ntawm tus kheej kheej yog tib yam li qhov ntawm txoj kev loj hlob ntawm zaj yeeb yaj kiab, tiam sis perpendicular rau zaj duab xis interface, thiab muaj ntau ntau yam nruab nrab ntawm cov cylinders. Ntsuas qhov sib txawv tag nrho hauv zaj duab xis los ntawm kev ntim kom txaus:

Puv ntoob (P) = qhov ntim ntawm qhov yeeb yaj duab (lub tog raj kheej) / lub ntim ntawm zaj duab xis (kheej kheej + pore)

Kev txhaws ceev yog ib qho tseem ceeb ntawm cov khoom kub thiab feem ntau, cov ciaj ciam phom loj zuj zus tuaj nrog rau qhov nce ntawm substrate. Feem ntau, nce tus nqi evaporation tuaj yeem ua rau kom puv ntoob, thiab cov nyhuv ntawm qhov evaporation tus nqi yog qhov tshwj xeeb tshaj yog thaum naam yog tsawg dua. Cov pob ntim kuj nce nrog qhov nce ntawm kev ua kom tuab tuab. Qhov no ntshe vim yog qhov hloov ntawm cov qauv hauv xeev ntawm zaj duab xis thaum lub sijhawm ua yeeb yaj kiab. Nws kuj yuav yog vim qhov blockage ntawm qee qhov ntawm cov yeeb yaj kiab pores hauv zaj yeeb yaj kiab uas ua tiav.