Isiphumo sokumanzisa, imfuneko: HLB: 7-9
Ukumanzisa kuchazwa njengemeko apho igesi efunxwa kumphezulu oqinileyo isuswa lulwelo. Izinto ezinokuphucula lo mthamo wokufuduka zibizwa ngokuba zii-wetting agents. Ukumanzisa ngokuqhelekileyo kuhlulwe ngeentlobo ezintathu: ukumanzisa okunxibelelanayo (ukumanzisa okunamathelayo), ukumanzisa okuntywilisiweyo (ukumanzisa okunzulu), kunye nokumanzisa okusasazekayo (ukusasazeka). Phakathi kwezi, ukusasazeka kubonisa umgangatho ophezulu wokumanzisa, kwaye i-coefficient yokusasazeka idla ngokusetyenziswa njengesalathisi sokuvavanya ukusebenza kokumanzisa phakathi kweenkqubo ezahlukeneyo. Ukongeza, i-angle yokuqhagamshelana nayo ikwayindlela yokugweba umgangatho wokumanzisa. Ii-surfactants zingasetyenziselwa ukulawula inqanaba lokumanzisa phakathi kwezigaba zolwelo kunye neziqinileyo.
Kwishishini lee-pesticide, ezinye ii-granular formulations kunye nee-dust powders nazo ziqulathe inani elithile le-surfactants. Injongo yazo kukuphucula ukunamathela kunye nobungakanani be-pesticide kwindawo ekujoliswe kuyo, ukukhawulezisa izinga lokukhululwa kunye nokwandisa indawo yokusasazeka kwezithako ezisebenzayo phantsi kweemeko ezimanzi, ngaloo ndlela kuphucula ukusebenza kakuhle kokuthintela izifo kunye nonyango.
Kwishishini lezinto zokuthambisa, izinto ezisurfactants zisebenza njengeemulsifiers kwaye zizinto ezibalulekileyo kwiimveliso zokhathalelo lolusu ezifana neekhrimu, iilotion, izicoci zobuso kunye nezisusa izimonyo.
I-Micelles kunye ne-Solubilization,iimfuno: C > CMC (HLB 13–18)
Uxinzelelo oluncinci apho iimolekyuli ze-surfactant zidibana khona ukuze zenze ii-micelles. Xa uxinzelelo ludlula ixabiso le-CMC, iimolekyuli ze-surfactant zizihlela ngokwazo zibe zizakhiwo ezifana nolwakhiwo olujikelezayo, olufana nenduku, olufana ne-lamellar, okanye olufana nepleyiti.
Iinkqubo zokunyibilikisa ziinkqubo zokulinganisela ze-thermodynamic. Okukhona i-CMC isezantsi kwaye inqanaba lokudibana liphezulu, kokukhona i-maximum additive concentration (MAC) inkulu. Isiphumo sobushushu ekunyibilikiseni sibonakala kwiinkalo ezintathu: sichaphazela ukwakheka kwe-micelle, ukunyibilikisa kwee-solubilizates, kunye nokunyibilikisa kwee-surfactants ngokwazo. Kwii-ionic surfactants, ukunyibilikisa kwazo kuyanda kakhulu xa kushushu, kwaye ubushushu apho oku kunyuka ngequbuliso kwenzeka khona bubizwa ngokuba yi-Krafft point. Okukhona i-Krafft point iphezulu, kokukhona i-critical micelle concentration iphantsi.
Kwi-polyoxyethylene nonionic surfactants, xa ubushushu bunyuka bufikelela kwinqanaba elithile, ukunyibilika kwazo kwehla kakhulu kwaye imvula iyenzeka, nto leyo ebangela ukuba isisombululo sijike sibe mdaka. Le nto yaziwa ngokuba yi-clouding, kwaye ubushushu obuhambelanayo bubizwa ngokuba yi-cloud point. Kwi-surfactants ezinobude obufanayo be-polyoxyethylene chain, kokukhona inde i-hydrocarbon chain, kokukhona i-cloud point iphantsi; ngokuchaseneyo, ngobude obufanayo be-hydrocarbon chain, kokukhona inde i-polyoxyethylene chain, kokukhona i-cloud point iphakama.
Izinto ezingezona ezo ziphilayo (umz., ibenzene) zinobunyibiliko obuphantsi kakhulu emanzini. Nangona kunjalo, ukongeza ii-surfactants ezifana ne-sodium oleate kunokunyusa kakhulu ubunyibiliko be-benzene emanzini—inkqubo ebizwa ngokuba yi-solubilization. Ukunyibilika kwahlukile ekunyibilikeni okuqhelekileyo: i-benzene enyibilikayo ayisasazeki ngokulinganayo kwiimolekyuli zamanzi kodwa ibanjwe ngaphakathi kwee-micelles ezenziwe zii-ion ze-oleate. Izifundo ze-X-ray diffraction ziqinisekisile ukuba zonke iintlobo zee-micelles ziyanda ukuya kumanqanaba ahlukeneyo emva kokunyibilika, ngelixa iipropati ze-colligative zesisombululo siphela zihlala zingatshintshi.
Njengoko uxinano lwee-surfactants emanzini lusanda, ii-molecules ze-surfactant ziqokelelana phezu kolwelo ukuze zenze umaleko we-monomolecular odibeneyo, ojolise kakhulu. Ii-molecules ezingaphezulu kwi-bulk phase zihlangana kunye namaqela azo e-hydrophobic ajonge ngaphakathi, enza ii-micelles. Uxinano oluncinci olufunekayo ukuqalisa ukwakheka kwe-micelle luchazwa njenge-critical micelle concentration (CMC). Kule concentration, isisombululo siyaphambuka kwindlela efanelekileyo yokuziphatha, kwaye inqaku elicacileyo le-inflection livela kwi-surface tension vs. concentration curve. Ukunyusa ngakumbi uxinano lwe-surfactant akuyi kunciphisa uxinano lomphezulu; endaweni yoko, kuya kukhuthaza ukukhula okuqhubekayo kunye nokuphindaphinda kwee-micelles kwi-bulk phase.
Xa iimolekyuli ze-surfactant zisasazeka kwisisombululo kwaye zifikelela kumda othile woxinzelelo, zidibana ukusuka kwiimonomers zomntu ngamnye (ii-ion okanye iimolekyuli) zibe zii-colloidal aggregates ezibizwa ngokuba yi-micelles. Olu tshintsho lubangela utshintsho olukhawulezileyo kwiimpawu zomzimba nezekhemikhali zesisombululo, kwaye uxinzelelo apho oku kwenzeka khona yi-CMC. Inkqubo yokwakheka kwe-micelle ibizwa ngokuba yi-micellization.
Ukwakheka kwee-micelles kwizisombululo ze-surfactant zamanzi yinkqubo exhomekeke kuxinzelelo. Kwizisombululo ezinyibilikiswe kakhulu, amanzi nomoya ziphantse zihlangane ngqo, ngoko uxinzelelo lomphezulu luyehla kancinci, luhlala lusondele kolo lwamanzi acocekileyo, kwaye zimbalwa kakhulu iimolekyuli ze-surfactant ezisasazeke kwisigaba sobuninzi. Njengoko uxinzelelo lwe-surfactant lusanda ngokulinganisela, iimolekyuli zingena ngokukhawuleza kumphezulu wamanzi, zinciphisa indawo yoqhagamshelwano phakathi kwamanzi nomoya kwaye zibangele ukwehla okukhulu koxinzelelo lomphezulu. Okwangoku, ezinye iimolekyuli ze-surfactant kwisigaba sobuninzi ziyahlangana kunye namaqela azo ahambelanayo e-hydrophobic, zenze ii-micelles ezincinci.
Njengoko uxinzelelo luqhubeka lunyuka kwaye isisombululo sifikelela kwi-saturation adsorption, ifilimu ye-monomolecular egcweleyo iyenzeka kumphezulu wolwelo. Xa uxinzelelo lufika kwi-CMC, uxinzelelo lomphezulu wesisombululo lufikelela kwixabiso laso elincinci. Ngaphaya kwe-CMC, ukonyusa uxinzelelo lwe-surfactant akuchaphazeli kangako uxinzelelo lomphezulu; endaweni yoko, kwandisa inani kunye nobukhulu bee-micelles kwisigaba sobuninzi. Isisombululo emva koko silawulwa yi-micelles, ezisebenza njengee-microreactors ekuhlanganiseni ii-nanopowders. Ngokukhula okuqhubekayo koxinzelelo, inkqubo itshintshela kancinci kwimo ye-crystalline yolwelo.
Xa uxinzelelo lwesisombululo se-surfactant esimanzi sifikelela kwi-CMC, ukwakheka kwee-micelles kuyacaca ngoxinzelelo olukhulayo. Oku kubonakala ngenqaku lokutshintsha koxinzelelo kumphezulu we-surface vs. log concentration curve (γ–log c curve), kunye nokuvela kweempawu zomzimba nezekhemikhali ezingezizo ezifanelekileyo kwisisombululo.
Ii-Ionic surfactant micelles zithwala ii-surface charges eziphezulu. Ngenxa yokutsalana kwe-electrostatic, ii-counterions zitsalwa kumphezulu we-micelle, zinciphisa inxalenye yee-positive kunye ne-negative charges. Nangona kunjalo, xa ii-micelles zenze izakhiwo ezitshajiweyo kakhulu, amandla okulibazisa e-ionic atmosphere eyenziwe zii-counterions ayanda kakhulu—ipropati enokusetyenziswa ukulungisa ukusasazeka kwee-nanopowders. Ngenxa yezi zizathu zimbini, ukuhanjiswa okulinganayo kwesisombululo kwehla ngokukhawuleza ngokwanda koxinzelelo ngaphaya kwe-CMC, okwenza le ngongoma ibe yindlela ethembekileyo yokumisela uxinzelelo olubalulekileyo lwe-micelle ye-surfactants.
Ulwakhiwo lwe-ionic surfactant micelles ludla ngokuba yingqukuva, luqulathe iindawo ezintathu: i-core, i-shell, kunye ne-diffuse electric double layer. I-core yenziwe nge-hydrophobic hydrocarbon chains, efana ne-liquid hydrocarbons, enobubanzi obuqala kwi-1 ukuya kwi-2.8 nm. Amaqela e-methylene (-CH₂-) akufutshane namaqela e-polar head ane-partial polarity, egcina ezinye iimolekyuli zamanzi ezijikeleze i-core. Ngoko ke, i-micelle core iquletheamanzi amaninzi avalelekileyo, kwaye la maqela e-CH₂- akadibani ngokupheleleyo ne-hydrocarbon core efana nolwelo kodwa endaweni yoko enza inxalenye yegobolondo le-micelle elingelolwelo.
Iqokobhe le-micelle likwaziwa ngokuba yi-micelle-water interface okanye i-surface phase. Alibhekiseli kwi-macroscopic interface phakathi kwe-micelles namanzi kodwa endaweni yoko libhekisa kummandla ophakathi kwe-micelles kunye nesisombululo se-monomeric aqueous surfactant. Kwi-ionic surfactant micelles, iqokobhe lenziwe yi-inside Stern layer (okanye i-fixed adsorption layer) ye-electric double layer, enobukhulu obuyi-0.2 ukuya kwi-0.3 nm. Iqokobhe aliqulathanga kuphela amaqela e-ionic head of surfactants kunye nenxalenye ye-bound counterions kodwa kunye ne-hydration layer ngenxa ye-hydration yezi ions. Iqokobhe le-micelle alikho umphezulu ogudileyo kodwa liyi-"rough" interface, ngenxa yokuguquguquka okubangelwa kukuhamba kobushushu kwee-surfactant monomer molecules.
Kwiindawo ezingezizo zamanzi (ezisekelwe kwioyile), apho iimolekyuli zeoyile zixhaphakileyo, amaqela e-hydrophilic e-surfactants ahlangana ngaphakathi ukuze enze i-polar core, ngelixa ii-hydrocarbon chain ze-hydrophobic zenza igobolondo langaphandle le-micelle. Olu hlobo lwe-micelle lunesakhiwo esiguqulweyo xa luthelekiswa nee-aqueous micelles eziqhelekileyo kwaye ngoko ke lubizwa ngokuba yi-reverse micelle; ngokwahlukileyo, ii-micelles ezenziwe emanzini zibizwa ngokuba yi-normal micelles. Umfanekiso 4 ubonisa imodeli yesicwangciso se-reverse micelles ezenziwe zii-surfactants kwizisombululo ezingezizo zamanzi. Kwiminyaka yakutshanje, ii-reverse micelles zisetyenziswe kakhulu ekuqulunqweni nasekulungiseleleni abathwali beziyobisi ze-nanoscale, ngakumbi ekufakweni kwezidakamizwa ze-hydrophilic.
Ixesha leposi: Disemba-26-2025