Umphumela wokumanzisa, imfuneko: HLB: 7-9
Ukumanzisa kuchazwa njengento lapho igesi efakwe endaweni eqinile isuswa khona uketshezi. Izinto ezingathuthukisa lo mthamo wokufuduka zibizwa ngokuthi ama-wetting agents. Ukumanzisa ngokuvamile kuhlukaniswa ngezinhlobo ezintathu: ukumanzisa kokuthintana (ukumanzisa okunamathelayo), ukumanzisa kokucwilisa (ukumanzisa okujulile), kanye nokumanzisa kokusakaza (ukusabalala). Phakathi kwalokhu, ukusabalala kumelela izinga eliphakeme kakhulu lokumanzisa, futhi i-coefficient yokusabalalisa ivame ukusetshenziswa njengesibonakaliso sokuhlola ukusebenza kokumanzisa phakathi kwezinhlelo ezahlukene. Ngaphezu kwalokho, i-angle yokuxhumana nayo iyisici sokwahlulela ikhwalithi yokumanzisa. Ama-surfactant angasetshenziswa ukulawula izinga lokumanzisa phakathi kwezigaba zoketshezi neziqinile.
Embonini yezibulala-zinambuzane, ezinye izinhlobo ze-granular kanye ne-dust powders nazo ziqukethe inani elithile lama-surfactants. Inhloso yazo ukuthuthukisa ukunamathela kanye nenani lokufakwa kwesibulala-zinambuzane endaweni eqondiwe, ukusheshisa izinga lokukhululwa kanye nokwandisa indawo yokusabalala kwezithako ezisebenzayo ngaphansi kwezimo ezimanzi, ngaleyo ndlela kuthuthukiswe ukusebenza kahle kokuvimbela nokwelapha izifo.
Embonini yezimonyo, ama-surfactant asebenza njenge-emulsifiers futhi ayizingxenye ezibalulekile emikhiqizweni yokunakekelwa kwesikhumba efana nama-creams, ama-lotion, izihlanzi zobuso kanye nezisusa izimonyo.
Ama-Micelles kanye nokuncibilika,izidingo: C > CMC (HLB 13–18)
Ukuhlushwa okuncane kakhulu lapho ama-molecule e-surfactant ehlangana khona ukuze akhe ama-micelle. Lapho ukuhlushwa kudlula inani le-CMC, ama-molecule e-surfactant azihlela abe izakhiwo ezifana nokuma okuyisiyingi, okufana nenduku, i-lamellar, noma okufana nepuleti.
Izinhlelo zokuncibilikisa ziyizinhlelo zokulinganisela ze-thermodynamic. Uma i-CMC iphansi futhi izinga lokuhlangana liphakeme, kulapho kuba khona ukugcwala okukhulu kwe-additive concentration (MAC). Umphumela wokushisa ekuncibilikiseni ubonakala ezicini ezintathu: kuthonya ukwakheka kwe-micelle, ukuncibilikisa kwama-solubilizates, kanye nokuncibilika kwama-surfactants uqobo. Kuma-ionic surfactants, ukuncibilika kwawo kuyanda kakhulu ngokushisa okukhuphukayo, futhi izinga lokushisa lapho lokhu kukhula okungazelelwe kwenzeka khona libizwa ngokuthi i-Krafft point. Uma i-Krafft point iphakeme, kulapho ukugcwala kwe-critical micelle kunciphisa khona.
Kuma-surfactants e-polyoxyethylene angewona ama-ionic, lapho izinga lokushisa likhuphuka liye ezingeni elithile, ukuncibilika kwawo kwehla kakhulu futhi imvula ivele, okwenza ikhambi liphenduke i-turbid. Lesi simo saziwa ngokuthi i-clouding, futhi izinga lokushisa elihambisanayo libizwa ngokuthi i-cloud point. Kuma-surfactants anobude obufanayo be-polyoxyethylene chain, uma i-hydrocarbon chain inde, i-cloud point iphansi; ngokuphambene nalokho, ngobude obufanayo be-hydrocarbon chain, uma i-polyoxyethylene chain inde, i-cloud point iphakeme.
Izinto ezingezona ezi-organic (isb., i-benzene) zinokuncibilika okuphansi kakhulu emanzini. Kodwa-ke, ukufaka ama-surfactants njenge-sodium oleate kungathuthukisa kakhulu ukuncibilika kwe-benzene emanzini—inqubo ebizwa ngokuthi ukuncibilika. Ukuncibilika kuhlukile ekuncibilikeni okuvamile: i-benzene encibilikile ayihlakazeki ngokulinganayo kuma-molecule amanzi kodwa ibanjwe ngaphakathi kwama-micelles akhiwe ama-ion e-oleate. Izifundo ze-X-ray diffraction ziqinisekisile ukuthi zonke izinhlobo zama-micelles zanda zibe amazinga ahlukahlukene ngemva kokuncibilika, kuyilapho izakhiwo ze-colligative zesisombululo sonke zihlala zingashintshi kakhulu.
Njengoba ukugcwala kwama-surfactant emanzini kwanda, ama-molecule e-surfactant aqoqana phezu koketshezi ukuze akhe ungqimba oluhlanganisiwe, oluqondiswe eduze. Ama-molecule amaningi esigabeni esikhulu ahlangana namaqembu awo angathandi amanzi abheke ngaphakathi, akha ama-micelle. Ukugcwala okuncane okudingekayo ukuqala ukwakheka kwe-micelle kuchazwa njenge-critical micelle concentration (CMC). Kulokhu kugcwala, isixazululo siyaphambuka ekuziphatheni okuhle, futhi iphuzu elihlukile lokushintshashintsha livela ku-surface tension vs. concentration curve. Ukwandisa ukugcwala kwe-surfactant ngeke kusanciphisa ukugcwala kobuso; kunalokho, kuzokhuthaza ukukhula okuqhubekayo kanye nokuphindaphinda kwama-micelle esigabeni esikhulu.
Lapho ama-molecule e-surfactant ehlakazeka esixazululweni futhi efinyelela umkhawulo othile wokuhlushwa, ahlangana kusuka kuma-monomers ngamanye (ama-ion noma ama-molecule) abe ama-colloidal aggregates abizwa ngokuthi ama-micelles. Lokhu kuguquka kubangela izinguquko ezisheshayo ezakhiweni zomzimba nezamakhemikhali zesisombululo, futhi ukuhlushwa okwenzeka kukho yi-CMC. Inqubo yokwakheka kwe-micelle ibizwa ngokuthi i-micellis.
Ukwakheka kwama-micelles ezixazululweni ze-surfactant zamanzi kuyinqubo encike ekugxilweni. Ezixazululweni ezincibilikisiwe kakhulu, amanzi nomoya cishe kuthintana ngqo, ngakho-ke ukucindezelwa kobuso kwehla kancane, kuhlale kusondelene nokwamanzi ahlanzekile, ngama-molecule ambalwa kakhulu e-surfactant ahlakazekile esigabeni esikhulu. Njengoba ukugxilwa kwe-surfactant kukhuphuka ngokulinganisela, ama-molecule anamathela ngokushesha ebusweni bamanzi, anciphise indawo yokuxhumana phakathi kwamanzi nomoya futhi abangele ukwehla okukhulu kokucindezelwa kobuso. Okwamanje, amanye ama-molecule e-surfactant esigabeni esikhulu ahlangana namaqembu awo angenawo umoya, akha ama-micelles amancane.
Njengoba ukuhlushwa kuqhubeka nokwenyuka futhi isixazululo sifinyelela ekumuncweni kokugcwala, kwakheka ifilimu eligcwele kakhulu le-monomolecular ebusweni boketshezi. Lapho ukuhlushwa kufinyelela ku-CMC, ukuhlushwa kobuso besixazululo kufinyelela inani laso eliphansi. Ngale kwe-CMC, ukukhulisa ukuhlushwa kwe-surfactant akukuthinti kangako ukuhlushwa kobuso; kunalokho, kwandisa inani nosayizi wama-micelles esigabeni esikhulu. Isixazululo sibe sesibuswa ama-micelles, asebenza njengama-microreactors ekwakhiweni kwama-nanopowders. Ngokukhula okuqhubekayo kokuhlushwa, uhlelo lushintsha kancane kancane luye esimweni se-crystalline yoketshezi.
Lapho ukugcwala kwesixazululo se-surfactant esimanzi sifika ku-CMC, ukwakheka kwama-micelles kuba yinto evelele ngokwanda kokugcwala. Lokhu kubonakala ngephuzu lokushintshashintsha kwe-surface tension vs. log concentration curve (γ–log c curve), kanye nokuvela kwezakhiwo zomzimba nezamakhemikhali ezingezona ezifanelekile esixazululweni.
Ama-micelle e-Ionic surfactant athwala amacala aphezulu obuso. Ngenxa yokukhanga kwe-electrostatic, ama-counterion akhangwa ebusweni be-micelle, okwenza ingxenye yamacala amahle nangalungile ibe buthakathaka. Kodwa-ke, uma ama-micelle akha izakhiwo ezishajeke kakhulu, amandla okubambezela emkhathini we-ionic owakhiwe ama-counterion anda kakhulu—isici esingasetshenziswa ukulungisa ukuhlakazeka kwama-nanopowders. Ngenxa yalezi zizathu ezimbili, ukuhanjiswa okufanayo kwesisombululo kwehla ngokushesha ngokwanda kokugxila ngale kwe-CMC, okwenza leli phuzu libe yindlela ethembekile yokunquma ukuhlushwa kwe-micelle ebalulekile yama-surfactants.
Isakhiwo sama-micelle e-ionic surfactant ngokuvamile siyindilinga, sakhiwe izingxenye ezintathu: umongo, igobolondo, kanye nesendlalelo esiphindwe kabili sikagesi esisakazekile. Umongo wakhiwe ngamaketanga e-hydrophobic hydrocarbon, afana nama-hydrocarbon aketshezi, anobubanzi obusukela cishe ku-1 kuya ku-2.8 nm. Amaqembu e-methylene (-CH₂-) aseduze namaqembu ekhanda le-polar ane-polarity engaphelele, agcina amanye ama-molecule amanzi azungeze umongo. Ngakho-ke, umongo we-micelle uquketheinani elikhulu lamanzi avalelekile, futhi la maqembu e-CH₂- awahlanganisiwe ngokugcwele enkabeni ye-hydrocarbon efana noketshezi kodwa kunalokho akha ingxenye yegobolondo le-micelle elingelona uketshezi.
Igobolondo le-micelle liyaziwa nangokuthi i-interface ye-micelle-water noma isigaba sobuso. Alibhekiseli ku-interface ye-macroscopic phakathi kwe-micelles namanzi kodwa kunalokho libhekisela esifundeni esiphakathi kwe-micelles nesisombululo se-monomeric aqueous surfactant. Ku-micelles ye-ionic surfactant, igobolondo lakhiwa ungqimba olungaphakathi lwe-Stern (noma ungqimba olugxilile lwe-adsorption) lwengqimba ephindwe kabili kagesi, enobukhulu obungaba ngu-0.2 kuya ku-0.3 nm. Igobolondo aliqukethe kuphela amaqembu ekhanda le-ionic ama-surfactants kanye nengxenye ye-bound counterions kodwa futhi nongqimba lwe-hydration ngenxa ye-hydration yala ma-ion. Igobolondo le-micelle aliyona indawo ebushelelezi kodwa kunalokho liyi-interface "enzima", umphumela wokushintshashintsha okubangelwa ukunyakaza kokushisa kwama-molecule e-surfactant monomer.
Ezindaweni ezingezona ezimanzi (ezisekelwe ku-oyela), lapho ama-molecule kawoyela ebusa khona, amaqembu e-hydrophilic ama-surfactants ahlangana ngaphakathi ukuze akhe umongo we-polar, kuyilapho amaketanga e-hydrocarbon angenamanzi akha igobolondo langaphandle le-micelle. Lolu hlobo lwe-micelle lunesakhiwo esiguquliwe uma luqhathaniswa nama-micelle ajwayelekile angenamanzi ngakho-ke lubizwa ngokuthi i-reverse micelle; ngokuphambene nalokho, ama-micelle akhiwe emanzini abizwa ngokuthi ama-micelles ajwayelekile. Isithombe 4 sibonisa imodeli ye-schematic yama-micelles angemuva akhiwe ama-surfactants ezixazululweni ezingezona ezimanzi. Eminyakeni yamuva nje, ama-micelles angemuva asetshenziswe kabanzi ekuhlanganiseni nasekulungiseleleni abathwali bezidakamizwa ze-nanoscale, ikakhulukazi ekufakweni kwezidakamizwa ze-hydrophilic.
Isikhathi sokuthunyelwe: Disemba-26-2025