Amasomo y'ubushakashatsi
Kubera ko ari umutungo kamere, mwinshi kandi ushobora kongera gukoreshwa, selulose ihura n'imbogamizi zikomeye mu mikoreshereze yayo ifatika bitewe n'ubushobozi bwayo bwo kudashonga no gushonga gake. Ubucucike bwinshi bwa kristali n'imigozi ya hydrogen ifite ubucucike bwinshi mu miterere ya selulose bituma ibora ariko ntishonge mu gihe cyo kuyifata, kandi ntishonge mu mazi no mu bintu byinshi biyungurura ibinyabuzima. Ibikomoka kuri byo bikorwa no gupima no gupima amatsinda ya hydroxyl ku bice bya anhydroglucose mu muyoboro wa polymer, kandi bizagaragaza imiterere itandukanye ugereranije na selulose karemano. Uburyo selulose ipima ether bushobora kubyara ether nyinshi za selulose zishonga mu mazi, nka methyl cellulose (MC), hydroxyethyl cellulose (HEC) na hydroxypropyl cellulose (HPC), zikoreshwa cyane mu biribwa, mu mavuta yo kwisiga, mu miti no mu buvuzi. CE ishonga mu mazi ishobora gukora polymeri zifatanye na hydrogen hamwe na aside polycarboxylic na polyphenols.
Guteranya urwego ku rundi (Layer-by-layer assemblies - LBL) ni uburyo bwiza bwo gutegura filime nto za polymer. Ibi bikurikira bivuga cyane cyane ihuriro rya LBL rya CE eshatu zitandukanye za HEC, MC na HPC na PAA, bigereranya imyitwarire yazo, kandi bigasesengura ingaruka z'ibintu bisimbura ihuriro rya LBL. Reba ingaruka za pH ku bugari bwa filime, n'itandukaniro ritandukanye rya pH ku miterere ya filime no kuyisesa, kandi utegure imiterere yo kwinjiza amazi ya CE/PAA.
Ibikoresho byo kugerageza:
Aside ya Polyacrylic (PAA, Mw = 450.000). Uburemere bw'umuti w'amazi wa hydroxyethylcellulose (HEC) wa 2wt.% ni 300 mPa·s, naho urwego rwo gusimbuza ni 2.5. Methylcellulose (MC, umuti w'amazi wa 2wt.% ufite uburemere bwa 400 mPa·s n'urwego rwo gusimbuza 1.8). Hydroxypropyl cellulose (HPC, umuti w'amazi wa 2wt.% ufite uburemere bwa 400 mPa·s n'urwego rwo gusimbuza 2.5).
Gutegura filime:
Byateguwe hakoreshejwe uburyo bwa crystal layer assemblée kuri silicon kuri 25°C. Uburyo bwo kuvura bwa slide matrix ni ubu bukurikira: shyira mu gikoresho cya aside (H2SO4/H2O2, 7/3Vol/VOL) mu gihe cy'iminota 30, hanyuma woge n'amazi ya deionized inshuro nyinshi kugeza pH ibaye ntarengwa, hanyuma ubyumishe na azote nziza. LBL assemblée ikorwa hakoreshejwe imashini zikora. Substrate yashyizwe mu gikoresho cya CE (0.2 mg/mL) n'igikoresho cya PAA (0.2 mg/mL), buri gikoresho cyashyizwe mu mazi mu gihe cy'iminota 4. Hakozwe inshuro eshatu zo koza umunota 1 buri kimwe mu mazi ya deionized hagati ya buri gikoresho kugira ngo hakureho polymer ifatanye neza. Ingano ya pH y'igikoresho cyo guteranya n'igikoresho cyo koza byombi byahinduwe kuri pH 2.0. Filimi zateguwe zigaragazwa nka (CE/PAA)n, aho n yerekana uruziga rw'igikoresho. (HEC/PAA)40, (MC/PAA)30 na (HPC/PAA)30 ahanini zateguwe.
Imiterere ya filime:
Ibipimo byo kurerekana hafi ya byose byafashwe amajwi kandi bigasesengurwa hifashishijwe NanoCalc-XR Ocean Optics, maze ubunini bwa filimi zashyizwe kuri silikoni burapimwa. Hakoreshejwe substrate ya silikoni idafite ibara nk'inyuma, spectrum ya FT-IR ya filimi ntoya iri kuri substrate ya silikoni yakusanyijwe kuri spectrometer ya infrared ya Nicolet 8700.
Imikoranire y'umugozi wa hydrogen hagati ya PAA na CE:
Guteranya HEC, MC na HPC hamwe na PAA muri filime za LBL. Imiterere ya infrared ya HEC/PAA, MC/PAA na HPC/PAA igaragara ku ishusho. Ibimenyetso bikomeye bya IR bya PAA na CES bigaragara neza muri spectra ya IR ya HEC/PAA, MC/PAA na HPC/PAA. Spectroscopy ya FT-IR ishobora gusesengura imiterere y'umugozi wa hydrogen hagati ya PAA na CES ikurikirana ihinduka ry'imirongo iranga imiterere. Umugozi wa hydrogen hagati ya CES na PAA ubaho cyane cyane hagati ya ogisijeni ya hydroxyl ya CES n'itsinda rya COOH rya PAA. Nyuma y'uko umugozi wa hydrogen ukozwe, umutuku urekura uhinduka ugana mu cyerekezo gito.
Hagaragaye uburebure bwa cm 1710-1 ku ifu ya PAA isanzwe. Iyo polyacrylamide yateranywaga mu mafirime afite CE zitandukanye, uburebure bwa HEC/PAA, MC/PAA na MPC/PAA bwari kuri cm 1718-1, cm 1720-1 na cm 1724-1, uko bikurikirana. Ugereranyije n'ifu ya PAA isanzwe, uburebure bwa HPC/PAA, MC/PAA na HEC/PAA bwahindutseho cm 14, 10 na 8-1, uko bikurikirana. Umugozi wa hydrogen hagati ya ogisijeni ya eteri na COOH uhagarika umugozi wa hydrogen hagati y'amatsinda ya COOH. Uko imigozi ya hydrogen ikorwa hagati ya PAA na CE, niko ihinduka ry'uburebure rya CE/PAA muri spectra ya IR rirushaho kwiyongera. HPC ifite urwego rwo hejuru rw'imigozi ya hydrogen, PAA na MC biri hagati, naho HEC ikaba ari yo iri hasi cyane.
Imyitwarire ikura ya filime zivanze za PAA na CE:
Imyitwarire ya PAA na CEs mu gukora filime mu gihe cyo guteranya LBL yakorewe ubushakashatsi hakoreshejwe QCM na interferometry ya spectral. QCM ikora neza mu gukurikirana imikurire ya filime aho iri mu bihe bya mbere byo guteranya. Interferometer za spectral zikwiriye filime zakuze mu gihe kirenga ukwezi 10.
Filime ya HEC/PAA yagaragaje iterambere ry’umurongo mu buryo burambuye mu gihe cyose cyo guteranya LBL, mu gihe filime za MC/PAA na HPC/PAA zagaragaje iterambere ry’umurongo mu ntangiriro z’iteranya hanyuma zigahinduka iterambere ry’umurongo mu buryo burambuye. Mu gace k’iteranya ry’umurongo, uko urwego rw’imiterere y’umurongo rurushaho kuba rwinshi, niko ubunini burushaho kwiyongera kuri buri cyiciro cy’iteranya.
Ingaruka za pH y'umuti ku mikurire ya filimi:
Agaciro ka pH k'umuti kagira ingaruka ku mikurire ya firime ya polimeri ifatanye na hydrogen. Nk'aho ari polyelectrolyte idakomeye, PAA izashyirwamo iyoni kandi igire amashanyarazi mabi uko pH y'umuti yiyongera, bityo bikabuza isano ya hydrogen. Iyo urugero rwa ionization ya PAA rugeze ku rwego runaka, PAA ntiyashoboraga guterana muri firime ifite hydrogen bond acceptors muri LBL.
Ubunini bwa firime bwaragabanutse bitewe n’ubwiyongere bwa pH y’umuti, kandi ubunini bwa firime bwaragabanutse mu buryo butunguranye kuri pH2.5 HPC/PAA na pH3.0-3.5 HPC/PAA. Ingingo y’ingenzi ya HPC/PAA ni pH 3.5, mu gihe iya HEC/PAA ari hafi 3.0. Ibi bivuze ko iyo pH y’umuti wo guteranya iri hejuru ya 3.5, firime ya HPC/PAA idashobora gukorwa, kandi iyo pH y’umuti iri hejuru ya 3.0, firime ya HEC/PAA idashobora gukorwa. Bitewe n’urugero rwo hejuru rw’ubufatanye bwa hydrogen bwa membrane ya HPC/PAA, agaciro ka pH k’ingenzi ka membrane ya HPC/PAA kari hejuru y’ako ka membrane ya HEC/PAA. Mu gisubizo kidafite umunyu, agaciro ka pH k’ingenzi ka complexes za HEC/PAA, MC/PAA na HPC/PAA kari hafi 2.9, 3.2 na 3.7, uko bikurikirana. pH y’ingenzi ya HPC/PAA iri hejuru ugereranyije na HEC/PAA, ibi bikaba bihuye n’iya LBL membrane.
Uburyo bwo kwinjiza amazi mu ruhu rwa CE/PAA:
CES ikungahaye ku matsinda ya hydroxyl ku buryo ifata amazi neza kandi ikabika neza. Dufashe urugero rwa HEC/PAA membrane, ubushobozi bwo kwinjiza membrane ya CE/PAA ifite hydrogen-bonded hydrogen mu mazi mu bidukikije bwizweho. Bigaragazwa na spectral interferometry, ubugari bwa filime buriyongera uko filime ifata amazi. Yashyizwe ahantu hari ubushuhe bushobora guhindurwa kuri 25°C mu gihe cy'amasaha 24 kugira ngo habeho uburinganire bwo kwinjiza amazi. Filimi zarumishijwe mu itanura ridafite umwuka (40°C) mu gihe cy'amasaha 24 kugira ngo zikurweho ubushuhe burundu.
Uko ubushuhe bwiyongera, firime irakomera. Mu buso buto bw'ubushuhe bwa 30%-50%, ubushyuhe buragabanuka cyane. Iyo ubushuhe burenze 50%, ubushyuhe burakura vuba. Ugereranyije n'agace ka PPVON/PAA gafite hydrogen-bond, agace ka HEC/PAA gashobora kwinjiza amazi menshi mu bidukikije. Mu gihe cy'ubushuhe bwa 70% (25°C), uburebure bw'agace ka PPVON/PAA bungana na 4%, mu gihe ubwinshi bwa HEC/PAA bungana na 18%. Ibisubizo byagaragaje ko nubwo hari amatsinda ya OH muri sisitemu ya HEC/PAA yagize uruhare mu ishyirwaho ry'imigozi ya hydrogen, hari umubare munini w'amatsinda ya OH akorana n'amazi mu bidukikije. Kubwibyo, sisitemu ya HEC/PAA ifite ubushobozi bwo kwinjiza amazi neza.
mu gusoza
(1) Sisitemu ya HPC/PAA ifite igipimo cyo hejuru cya hydrogen combination cya CE na PAA niyo ikura vuba cyane muri zo, MC/PAA iri hagati, naho HEC/PAA ikaba iri hasi cyane.
(2) Filime ya HEC/PAA yagaragaje uburyo bwo gukura bukurikije umurongo umwe mu gihe cyose cyo gutegura, mu gihe izindi filime ebyiri MC/PAA na HPC/PAA zagaragaje iterambere ryimbitse mu byiciro bike bya mbere, hanyuma zihinduka uburyo bwo gukura bukurikije umurongo umwe.
(3) Ikura rya firime ya CE/PAA rishingiye cyane ku gisubizo cya pH. Iyo pH y'igisubizo iri hejuru y'ingingo yayo y'ingenzi, PAA na CE ntibishobora guterana bikavamo firime. Uduce twa CE/PAA twakusanyijwe twashongeshejwe mu gisubizo cya pH iri hejuru.
(4) Kubera ko firime ya CE/PAA ikungahaye kuri OH na COOH, uburyo bwo kuyivura butuma ihuzwa. Ururenda rwa CE/PAA ruhuzwa rufite ubushobozi bwo guhagarara neza kandi ntirushongeshwa mu bisubizo bifite pH nyinshi.
(5) Filime ya CE/PAA ifite ubushobozi bwo kwinjiza amazi mu bidukikije neza.
Igihe cyo kohereza: Gashyantare-18-2023