Colloid systems yog qhov tseem ceeb hauv lub neej ntawm txhua tus neeg. Qhov no yog vim tsis tsuas yog lub fact tias yuav luag tag nrho cov kua roj ntsha nyob rau hauv ib tug muaj sia nyob tsim colloids. Tab sis muaj ntau yam xwm txheej ntuj (dua, smog), av, minerals, zaub mov, tshuaj kuj yog colloidal systems.
Chav tsev ntawm cov formations, xav txog lawv cov muaj pes tsawg leeg thiab cov khoom tshwj xeeb, suav tias yog macromolecule, lossis micelle. Cov qauv ntawm lub tom kawg yog nyob ntawm ntau yam, tab sis nws yog ib txwm ib tug multilayer particle. Niaj hnub nimno molecular kinetic txoj kev xav txiav txim siab colloidal cov kev daws teeb meem raws li ib qho tshwj xeeb ntawm cov kev daws teeb meem, nrog cov khoom loj ntawm cov kua nplaum.
Txoj kev kom tau txais cov tshuaj colloidal
Tus qauv ntawm micelle tsim thaum lub cev colloidal tshwm sim, ib feem nyob ntawm cov txheej txheem ntawm cov txheej txheem no. Txoj hauv kev kom tau txais cov colloids tau muab faib ua ob pawg sib txawv.
Txoj kev Dispersion yog txuam nrog kev sib tsoo ntawm cov khoom loj loj. Raws li cov txheej txheem ntawm cov txheej txheem no, cov txheej txheem hauv qab no yog qhov txawv.
- Kev kho dua tshiab. Yuav ua kom qhuav los yogtxoj kev ntub dej. Hauv thawj kis, cov khoom yog thawj zaug crushed, thiab tsuas yog tom qab ntawd cov kua ntxiv. Hauv qhov thib ob, cov khoom xyaw yog tov nrog cov kua, thiab tsuas yog tom qab ntawd nws hloov mus rau hauv homogeneous sib tov. Kev sib tsoo yog nqa tawm hauv cov zeb tshwj xeeb.
- Siab. Kev sib tsoo yog ua tiav vim qhov tseeb tias cov kuab tshuaj tau nkag mus rau hauv cov theem dispersed, uas yog nrog los ntawm kev nthuav dav ntawm nws cov khoom mus txog rau kev sib cais.
- Hluav taws xob poob siab dispersion. Demanded nyob rau hauv zus tau tej cov hlau sols. Nws yog nqa tawm los ntawm kev tso electrodes ua los ntawm cov hlau dispersible rau hauv cov kua, ua raws li los ntawm kev siv high voltage rau lawv. Yog li ntawd, lub voltaic arc yog tsim nyob rau hauv uas cov hlau yog txau thiab ces condenses mus rau hauv ib tug tov.
YDispersion by ultrasound. Cov khoom yuav tsum tau muab tso rau hauv cov kua thiab sonicated.
Cov qauv no tsim nyog rau ob qho tib si lyophilic thiab lyophobic colloidal hais. Cov qauv micelle tau ua tiav ib txhij nrog kev puas tsuaj ntawm cov qauv qub ntawm cov khoom.
Cov txheej txheem Condensation
Pab pawg thib ob ntawm txoj hauv kev raws li qhov loj me yog hu ua condensation. Cov txheej txheem no tuaj yeem ua raws li lub cev lossis tshuaj lom neeg tshwm sim. Txoj kev siv lub cev condensation muaj xws li hauv qab no.
- Hloov cov kuab tshuaj. Nws los mus rau kev hloov ntawm ib yam khoom los ntawm ib qho hnyav, nyob rau hauv uas nws dissolves zoo heev, mus rau lwm yam, nyob rau hauv uas lub solubility qis dua. Yog li ntawd, cov khoom me meyuav muab sib xyaw ua ke loj dua thiab cov tshuaj colloidal yuav tshwm sim.
- Vapour condensation. Ib qho piv txwv yog pos huab, nws cov khoom tuaj yeem nyob ntawm qhov chaw txias thiab maj mam loj tuaj.
Tshuaj condensation txoj kev suav nrog qee cov tshuaj tiv thaiv nrog los ntawm nag lossis daus ntawm cov qauv:
- Ion pauv: NaCl + AgNO3=AgCl↓ + NaNO3.
- Redox processes: 2H2S + O2=2S↓ + 2H2 O.
- Hydrolysis: Al2S3 + 6H2O=2Al(OH) 3↓ + 3H2S.
Cov xwm txheej rau cov tshuaj condensation
Cov qauv ntawm micelles tsim thaum cov tshuaj tiv thaiv no nyob ntawm qhov ntau dhau lossis tsis txaus ntawm cov tshuaj koom nrog hauv lawv. Tsis tas li ntawd, rau cov tsos ntawm cov kev daws teeb meem colloidal, nws yog ib qho tsim nyog yuav tsum tau soj ntsuam ntau yam kev mob uas tiv thaiv cov nag lossis daus ntawm ib qho chaw soluble:
- cov ntsiab lus ntawm cov tshuaj hauv cov tshuaj sib xyaw yuav tsum tsawg;
- lawv kev sib xyaw nrawm yuav tsum qis;
- ib qho kev daws yuav tsum tau ua ntau dhau.
Micelle structure
Qhov tseem ceeb ntawm micelle yog lub hauv paus. Nws yog tsim los ntawm ib tug loj tus naj npawb ntawm atoms, ions thiab molecules ntawm ib tug insoluble compound. Feem ntau cov tub ntxhais yog tus cwj pwm los ntawm cov qauv crystalline. Qhov saum npoo ntawm lub nucleus muaj qhov cia ntawm lub zog dawb, uas ua rau nws muaj peev xwm xaiv cov ions adsorb los ntawm ib puag ncig. Cov txheej txheem noua raws txoj cai Peskov, uas hais tias: nyob rau saum npoo ntawm cov khoom, cov ions feem ntau yog adsorbed uas muaj peev xwm ua tiav nws tus kheej siv lead ua lattice. Qhov no ua tau yog tias cov ions muaj feem cuam tshuam los yog zoo sib xws hauv cov xwm txheej thiab cov duab (qhov loj me).
Thaum lub sij hawm adsorption, ib txheej ntawm qhov zoo lossis qhov tsis zoo them ions, hu ua qhov kev txiav txim siab ions, yog tsim rau ntawm micelle core. Vim yog electrostatic rog, qhov tshwm sim tau them tag nrho attracts counterions (ions nrog tus nqi rov qab) los ntawm kev daws. Yog li, ib tug colloidal particle muaj ib tug multilayer qauv. Lub micelle tau txais ib txheej dielectric ua los ntawm ob hom kev them nyiaj rov qab.
YHydrosol BaSO4
Ua piv txwv, nws yog qhov yooj yim los txiav txim siab cov qauv ntawm barium sulfate micelle hauv cov tshuaj colloidal npaj rau ntau tshaj ntawm barium chloride. Cov txheej txheem no sib raug rau qhov sib npaug ntawm cov tshuaj tiv thaiv:
BaCl2(p) + Na2SO4(p)=BaSO 4(t) + 2NaCl(p).
me ntsis soluble hauv dej, barium sulfate tsim cov microcrystalline aggregate tsim los ntawm m-th tus naj npawb ntawm BaSO molecules4. Qhov saum npoo ntawm qhov sib sau no adsorbs n-th tus nqi ntawm Ba2+ ions. 2(n - x) Cl- ions txuas nrog rau txheej txheej ntawm qhov muaj peev xwm txiav txim siab ions. Thiab tus so ntawm cov counterions (2x) yog nyob rau hauv lub diffuse txheej. Ntawd yog, cov granule ntawm micelle no yuav raug nqi zoo.
Yog tias sodium sulfate noj ntau dhau, cesCov peev txheej txiav txim siab ions yuav yog SO 4 2- ions, thiab cov counterions yuav yog Na+. Hauv qhov no, tus nqi ntawm cov granule yuav tsis zoo.
Qhov piv txwv no qhia meej meej tias qhov kos npe ntawm tus nqi ntawm micelle granule ncaj qha nyob ntawm cov xwm txheej rau nws qhov kev npaj.
Qhia micelles
Qhov piv txwv yav dhau los tau pom tias cov qauv tshuaj ntawm micelles thiab cov mis uas qhia txog nws yog txiav txim siab los ntawm cov khoom uas tau noj ntau dhau. Cia peb xav txog txoj hauv kev ntawm kev sau cov npe ntawm ib tus neeg ntawm cov khoom siv colloidal siv piv txwv ntawm tooj liab sulfide hydrosol. Txhawm rau npaj nws, cov tshuaj sodium sulfide maj mam hliv rau hauv qhov ntau ntawm cov tshuaj tooj liab chloride:
CuCl2 + Na2S=CuS↓ + 2NaCl.
Tus qauv ntawm CuS micelle tau tshaj ntawm CuCl2 yog sau raws li hauv qab no:
{[mCuS]·nCu2+·xCl-}+(2n-x)·(2n-x)Cl-.
Cov qauv ntawm cov khoom sib xyaw ua ke
Nyob rau hauv square brackets sau cov mis ntawm ib tug sparingly soluble compound, uas yog lub hauv paus ntawm tag nrho cov particle. Nws yog feem ntau hu ua aggregate. Feem ntau, tus naj npawb ntawm cov molecules uas tsim cov aggregate yog sau nrog tsab ntawv Latin m.
Muaj peev xwm txiav txim siab ions muaj nyob rau hauv ntau dhau hauv kev daws teeb meem. Lawv nyob rau saum npoo ntawm cov aggregate, thiab nyob rau hauv cov qauv lawv tau sau tam sim ntawd tom qab square brackets. Tus naj npawb ntawm cov ions no yog qhia los ntawm lub cim n. Lub npe ntawm cov ions no qhia tias lawv cov nqi txiav txim siab tus nqi ntawm micelle granule.
A granule yog tsim los ntawm ib qho tseem ceeb thiab ib feemcounterions nyob rau hauv lub adsorption txheej. Tus nqi ntawm tus nqi granule yog sib npaug rau cov lej ntawm cov nqi ntawm qhov muaj peev xwm-txiav txim siab thiab adsorbed counterions: + (2n - x). Qhov seem ntawm cov counterions yog nyob rau hauv lub diffuse txheej thiab them nyiaj rau tus nqi ntawm cov granule.
Yog Na2S tau noj ntau dhau, tom qab ntawd rau cov tsim colloidal micelle cov qauv txheej txheem yuav zoo li:
{[m(CuS)]∙nS2–∙xNa+}–(2n – x) ∙(2n – x)Na+.
Micelles ntawm surfactants
Nyob rau hauv cov xwm txheej uas cov ntsiab lus ntawm cov khoom siv saum npoo av (surfactants) hauv dej siab dhau lawm, cov khoom sib xyaw ntawm lawv cov molecules (lossis ions) tuaj yeem pib tsim. Cov khoom loj no muaj cov duab ntawm ib lub kheej kheej thiab hu ua Gartley-Rebinder micelles. Nws yuav tsum raug sau tseg tias tsis yog txhua tus surfactants muaj peev xwm, tab sis tsuas yog cov uas qhov sib piv ntawm hydrophobic thiab hydrophilic qhov zoo tshaj plaws. Qhov piv no yog hu ua hydrophilic-lipophilic tshuav nyiaj li cas. Lub peev xwm ntawm lawv pawg polar los tiv thaiv cov tub ntxhais hydrocarbon los ntawm dej kuj ua lub luag haujlwm tseem ceeb.
Aggregates ntawm surfactant molecules yog tsim raws li qee txoj cai:
- tsis zoo li cov tshuaj tsis muaj molecular, cov khoom sib xyaw uas muaj xws li cov lej sib txawv ntawm cov molecules m, qhov muaj nyob ntawm cov micelles surfactant yog ua tau nrog tus lej ntawm cov molecules nruj me ntsis;
- yog rau cov tshuaj inorganic pib ntawm micellization yog txiav txim siab los ntawm kev txwv solubility, tom qab ntawd rau cov organic surfactants nws yog txiav txim siab los ntawm kev ua tiav ntawm qhov tseem ceeb ntawm micellization;
- ua ntej, tus naj npawb ntawm cov micelles hauv cov tshuaj nce ntxiv, thiab tom qab ntawd lawv qhov loj tuaj.
Kev cuam tshuam ntawm concentration ntawm cov duab micelle
Cov qauv ntawm surfactant micelles cuam tshuam los ntawm lawv cov concentration hauv cov tshuaj. Thaum ncav cuag qee qhov ntawm nws qhov tseem ceeb, colloidal hais pib sib cuam tshuam nrog ib leeg. Qhov no ua rau lawv cov duab hloov raws li hauv qab no:
- sphere hloov mus ua ellipsoid thiab ces mus rau hauv lub tog raj kheej;
- siab concentration ntawm lub tog raj kheej ua rau tsim cov theem hexagonal;
- nyob rau hauv qee kis, ib theem lamellar thiab cov khoom siv lead ua (xov xab npum) tshwm sim.
Type of micelles
Peb hom colloidal systems tau txawv raws li qhov peculiarities ntawm lub koom haum ntawm cov qauv sab hauv: suspensoids, micellar colloids, molecular colloids.
Suspensoids tuaj yeem hloov tsis tau cov colloids, nrog rau lyophobic colloids. Cov qauv no yog tsim rau kev daws teeb meem ntawm cov hlau, nrog rau lawv cov tebchaw (ntau oxides thiab ntsev). Cov qauv ntawm cov theem dispersed tsim los ntawm suspensoids tsis txawv ntawm cov qauv ntawm cov khoom siv compact. Nws muaj molecular lossis ionic crystal lattice. Qhov sib txawv ntawm kev tshem tawm yog qhov ntau dua dispersion. Irreversibility yog manifested nyob rau hauv lub peev xwm ntawm lawv cov kev daws teeb meem tom qab evaporation los ua ib tug qhuav precipitate, uas yuav tsis tau hloov mus rau hauv ib tug sol los ntawm yooj yim dissolution. Lawv hu ua lyophobic vim yog qhov tsis muaj zog ntawm kev sib cuam tshuam ntawm cov theem tawg thiab qhov nruab nrab dispersion.
Micellar colloids yog cov kev daws teeb meem uas nws cov colloidal hais tau tsimThaum ua cov diphilic molecules uas muaj pawg polar ntawm atoms thiab cov tsis-polar radicals. Piv txwv yog xab npum thiab surfactants. Molecules nyob rau hauv xws li micelles yog tuav los ntawm dispersion rog. Cov duab ntawm cov colloids tuaj yeem ua tsis tau tsuas yog kheej kheej xwb, tab sis kuj lamellar.
Molecular colloids yog qhov ruaj khov tsis muaj stabilizers. Lawv structural units yog tus kheej macromolecules. Cov duab ntawm colloid particle tuaj yeem sib txawv nyob ntawm seb cov khoom ntawm cov molecule thiab kev sib cuam tshuam intramolecular. Yog li cov kab molecule tuaj yeem ua tus pas nrig lossis lub kauj.
