Tasirin jika, buƙata: HLB: 7-9
Ana bayyana rijiyar a matsayin abin da ke faruwa inda iskar da ke sha a saman wani abu mai ƙarfi ta hanyar ruwa. Ana kiran abubuwan da za su iya ƙara wannan ƙarfin rijiyar. Rijiyar gabaɗaya ana rarraba ta zuwa nau'i uku: rijiyar hulɗa (rijiyar mannewa), rijiyar nutsewa (rijiyar nutsewa), da rijiyar yaɗa (rijiyar yaɗawa). Daga cikin waɗannan, yaɗawa yana wakiltar mafi girman ma'aunin rijiyar, kuma ana amfani da ma'aunin yaɗawa azaman alama don kimanta aikin rijiyar tsakanin tsarin daban-daban. Bugu da ƙari, kusurwar hulɗa kuma ma'auni ne don tantance ingancin rijiyar. Ana iya amfani da surfactants don sarrafa matakin rijiyar tsakanin matakan ruwa da ƙarfi.
A masana'antar magungunan kashe kwari, wasu nau'ikan ƙwayoyin cuta da foda masu ƙura suma suna ɗauke da wani adadin surfactants. Manufarsu ita ce inganta yawan mannewa da adana maganin kashe kwari a saman da ake so, hanzarta saurin fitarwa da kuma faɗaɗa yankin yaɗuwar sinadaran da ke aiki a ƙarƙashin yanayi mai danshi, ta haka ne za a inganta ingancin rigakafin cututtuka da magani.
A masana'antar kayan kwalliya, surfactants suna aiki a matsayin emulsifiers kuma sune abubuwan da ba makawa a cikin kayayyakin kula da fata kamar man shafawa, man shafawa, masu tsaftace fuska da masu cire kayan shafa.
Micelles da Narkewa,buƙatu: C > CMC (HLB 13–18)
Mafi ƙarancin yawan da ƙwayoyin surfactant ke haɗuwa da samar da micelles. Lokacin da yawan ya wuce ƙimar CMC, ƙwayoyin surfactant suna tsara kansu zuwa tsari kamar su siffar ƙwallo, kamar sanda, lamellar, ko kuma kamar faranti.
Tsarin narkewar sinadarai tsarin ma'aunin thermodynamic ne. Mafi ƙarancin CMC da kuma mafi girman matakin haɗin kai, mafi girman yawan ƙari (MAC). Tasirin zafin jiki akan narkewar sinadarai yana bayyana a fannoni uku: yana tasiri ga samuwar micelle, narkewar sinadarai, da kuma narkewar sinadarai da kansu. Ga masu samar da sinadarai masu ionic, narkewar sinadaransu yana ƙaruwa sosai tare da ƙaruwar zafin jiki, kuma zafin da wannan ƙaruwar sinadarai ke faruwa kwatsam ana kiransa da ma'aunin Krafft. Mafi girman ma'aunin Krafft, mafi ƙarancin yawan micelle.
Ga polyoxyethylene nonionic surfactants, idan zafin jiki ya tashi zuwa wani mataki, narkewarsu yana raguwa sosai kuma ruwan sama yana faruwa, wanda ke haifar da ruwan ya zama turbid. Wannan lamari ana kiransa da girgije, kuma zafin da ya dace ana kiransa da wurin girgije. Ga surfactants masu tsawon sarkar polyoxyethylene iri ɗaya, tsawon sarkar hydrocarbon, ƙarancin wurin girgije; akasin haka, tare da tsawon sarkar hydrocarbon iri ɗaya, tsawon sarkar polyoxyethylene, mafi girman wurin girgije.
Abubuwan da ba su da alaƙa da sinadarai masu rai (misali, benzene) suna da ƙarancin narkewa a cikin ruwa. Duk da haka, ƙara surfactants kamar sodium oleate na iya ƙara yawan narkewar benzene a cikin ruwa - wani tsari da ake kira narkewa. Narkewa ya bambanta da narkewar yau da kullun: benzene da aka narke ba a warwatse shi ɗaya a cikin ƙwayoyin ruwa ba amma an kama shi a cikin micelles da ions oleate suka samar. Nazarin diffraction na X-ray ya tabbatar da cewa duk nau'ikan micelles suna faɗaɗa zuwa matakai daban-daban bayan narkewa, yayin da halayen haɗin gwiwa na maganin gabaɗaya ba su canzawa ba.
Yayin da yawan surfactants a cikin ruwa ke ƙaruwa, ƙwayoyin surfactant suna taruwa a saman ruwa don samar da wani Layer mai kama da juna, mai tsari. Kwayoyin da suka wuce gona da iri a cikin tarin babban lokaci tare da ƙungiyoyin su masu son hydrophobic suna fuskantar ciki, suna samar da micelles. Mafi ƙarancin yawan da ake buƙata don fara samar da micelles an bayyana shi azaman mahimmancin yawan micelles (CMC). A wannan yawan, maganin yana karkacewa daga ɗabi'a mai kyau, kuma wani wuri daban na juyawa yana bayyana akan tashin hankali na saman da lanƙwasa taro. Ƙara yawan surfactant ba zai ƙara rage tashin hankali na saman ba; maimakon haka, zai haɓaka ci gaba da girma da ninka micelles a cikin babban lokaci.
Lokacin da ƙwayoyin surfactant suka bazu a cikin wani bayani suka isa wani takamaiman matakin tattarawa, suna haɗuwa daga monomers daban-daban (ions ko ƙwayoyin halitta) zuwa gauraye na colloidal da ake kira micelles. Wannan sauyi yana haifar da canje-canje kwatsam a cikin halayen zahiri da na sinadarai na maganin, kuma yawan da hakan ke faruwa shine CMC. Tsarin samuwar micelle ana kiransa micellization.
Samuwar micelles a cikin ruwan surfactant tsari ne da ya dogara da yawan maida hankali. A cikin ruwan da ya yi laushi sosai, ruwa da iska kusan suna haɗuwa kai tsaye, don haka tashin hankalin saman yana raguwa kaɗan kaɗan, yana kasancewa kusa da na ruwan tsarki, tare da ƙananan ƙwayoyin surfactant da suka bazu a cikin babban matakin. Yayin da yawan surfactant ke ƙaruwa kaɗan, ƙwayoyin suna shiga cikin ruwan da sauri, suna rage yankin hulɗa tsakanin ruwa da iska kuma suna haifar da raguwar tashin hankalin saman. A halin yanzu, wasu ƙwayoyin surfactant a cikin babban matakin tare da ƙungiyoyin su na hydrophobic sun daidaita, suna samar da ƙananan micelles.
Yayin da yawan sinadarin ke ci gaba da ƙaruwa kuma ruwan ya kai ga cikar sinadarin, wani fim mai cike da sinadarai (monomolecular) ya fito a saman ruwa. Lokacin da yawan sinadarin ya kai ga CMC, matsin lamba a saman ruwan ya kai ga mafi ƙarancin ƙima. Bayan CMC, ƙarin yawan sinadarin da ke cikin ruwan ba shi da tasiri sosai ga ƙarfin sinadarin; maimakon haka, yana ƙara yawan sinadarin da ke cikin ruwan. Sannan sinadarin da ke cikin ruwan yana mamaye ruwan, waɗanda ke aiki a matsayin microreactors a cikin haɗa sinadarin nanopowders. Tare da ci gaba da ƙaruwar yawan sinadarin, tsarin yana canzawa a hankali zuwa yanayin lu'ulu'u mai ruwa-ruwa.
Idan yawan sinadarin surfactant mai ruwa ya kai ga CMC, samuwar micelles zai bayyana tare da ƙaruwar yawan sinadarin. Wannan yana bayyana ta hanyar ma'aunin juyawa a cikin matsin lamba na saman da lanƙwasa yawan sinadarin log (γ–log c curve), tare da bayyanar halayen jiki da sinadarai marasa kyau a cikin maganin.
Micelles na ionic surfactant suna ɗauke da manyan caji na saman. Saboda jan hankalin lantarki, ana jan hankalin masu adawa zuwa saman micelle, wanda ke hana wani ɓangare na caji mai kyau da mara kyau. Duk da haka, da zarar micelles sun samar da tsari mai ƙarfi, ƙarfin da ke hana yanayin ionic da aka samar ta hanyar masu adawa yana ƙaruwa sosai - wani abu da za a iya amfani da shi don daidaita wargajewar nanopowders. Saboda waɗannan dalilai guda biyu, daidaitaccen watsawar maganin yana raguwa da sauri tare da ƙaruwar maida hankali fiye da CMC, wanda hakan ya sa wannan batu ya zama hanya mai inganci don tantance mahimmancin yawan micelle na surfactants.
Tsarin micelles na ionic surfactant yawanci yana da siffar zagaye, wanda ya ƙunshi sassa uku: tsakiya, harsashi, da kuma wani yanki mai faɗi na lantarki mai faɗi. Tsakiyar ta ƙunshi sarƙoƙin hydrocarbon masu kama da ruwa, waɗanda diamitansu ya kama daga kusan 1 zuwa 2.8 nm. Ƙungiyoyin methylene (-CH₂-) da ke kusa da ƙungiyoyin kan polar suna da ɓangaren polarity, suna riƙe da wasu ƙwayoyin ruwa a kusa da tsakiya. Don haka, tsakiyar micelle ta ƙunshiruwa mai yawa da aka makale, kuma waɗannan ƙungiyoyin -CH₂- ba a haɗa su gaba ɗaya cikin tsakiyar hydrocarbon mai kama da ruwa ba, amma a maimakon haka suna zama wani ɓangare na harsashin micelle mara ruwa.
Ana kuma san harsashin micelle da haɗin ruwa na micelle ko kuma matakin saman. Ba ya nufin haɗin macroscopic tsakanin micelles da ruwa ba, sai dai yankin da ke tsakanin micelles da maganin monomeric aquatic surfactant. Ga micelles na ionic surfactant, harsashin yana samuwa ne ta hanyar mafi girman Layer na Stern (ko madaidaicin Layer na sha) na layin lantarki mai kauri biyu, tare da kauri kusan 0.2 zuwa 0.3 nm. Ba wai kawai ya ƙunshi ƙungiyoyin kan ionic na surfactants da wani ɓangare na abubuwan da aka ɗaure ba, har ma da Layer na hydration saboda hydration na waɗannan ions. Shell ɗin micelle ba saman santsi bane amma a maimakon haka haɗin "mai tsauri", sakamakon canzawar da motsi na zafi na ƙwayoyin monomer na surfactant ke haifarwa.
A cikin hanyoyin da ba na ruwa ba (wanda ke tushen mai), inda ƙwayoyin mai suka fi rinjaye, ƙungiyoyin surfactants masu ruwa suna taruwa a ciki don samar da tsakiyar polar, yayin da sarƙoƙin hydrocarbon masu ruwa suna samar da harsashin waje na micelle. Wannan nau'in micelle yana da tsarin juyawa idan aka kwatanta da micelles na ruwa na gargajiya kuma saboda haka ana kiransa micelle na baya; akasin haka, micelles da aka samar a cikin ruwa ana kiransu micelles na yau da kullun. Hoto na 4 yana nuna samfurin tsari na micelles masu ruwa da aka samar ta hanyar surfactants a cikin mafita marasa ruwa. A cikin 'yan shekarun nan, an yi amfani da micelles masu ruwa da baya sosai wajen haɗawa da shirya masu ɗaukar magunguna nanoscale, musamman don lulluɓe magungunan hydrophilic.
Lokacin Saƙo: Disamba-26-2025