Semelo sa Lipatlisiso
E le mohloli oa tlhaho, o ngata le o ka nchafatsoang, cellulose e kopana le mathata a maholo lits'ebetsong tse sebetsang ka lebaka la thepa ea eona e sa qhibiliheng le e fokolang.Li-crystallinity tse phahameng le li-high-density hydrogen bonds ka har'a sebopeho sa cellulose li etsa hore e fokotsehe empa e se ke ea qhibiliha nakong ea ts'ebetso ea thepa, 'me e ke ke ea qhibiliha ka metsing le ka bongata ba metsoako ea lintho tse phelang.Li-derivatives tsa tsona li hlahisoa ke esterification le etherification ea lihlopha tsa hydroxyl ka li-unit tsa anhydroglucose tse ka har'a ketane ea polymer, 'me li tla bonts'a thepa e fapaneng ha e bapisoa le selulose ea tlhaho.Karabelo ea etherification ea selulose e ka hlahisa li-ether tse ngata tse qhibilihang ka metsing, tse kang methyl cellulose (MC), hydroxyethyl cellulose (HEC) le hydroxypropyl cellulose (HPC), tse sebelisoang haholo lijong, litlolo, litlhare le meriana.CE e qhibilihang ka metsi e ka etsa lipolymers tse kopantsoeng le hydrogen tse nang le li-polycarboxylic acid le polyphenols.
Kopano ea Layer-by-layer (LBL) ke mokhoa o sebetsang oa ho lokisa lifilimi tse tšesaane tse entsoeng ka polymer.Se latelang se hlalosa haholo-holo kopano ea LBL ea li-CE tse tharo tse fapaneng tsa HEC, MC le HPC tse nang le PAA, li bapisa boitšoaro ba tsona ba kopano, 'me li sekaseka tšusumetso ea ba nkang sebaka kopanong ea LBL.Batlisisa phello ea pH botenya ba filimi, le liphapang tse fapaneng tsa pH mabapi le ho etsoa ha filimi le ho qhibiliha, 'me u ntlafatse mekhoa ea ho monya metsi ea CE/PAA.
Lisebelisoa tsa Teko:
Polyacrylic acid (PAA, Mw = 450,000).The viscosity ea 2wt.% aqueous solution ea hydroxyethylcellulose (HEC) ke 300 mPa·s, 'me tekanyo ea ho fetola ke 2.5.Methylcellulose (MC, 2wt.% tharollo ea metsi e nang le viscosity ea 400 mPa·s le tekanyo ea ho fetola 1,8).Hydroxypropyl cellulose (HPC, 2wt.% tharollo ea metsi e nang le viscosity ea 400 mPa·s le tekanyo ea ho fetola 2.5).
Tokisetso ea filimi:
E hlophisitsoe ka kopano ea kristale ea mokelikeli holim'a silicon ka 25 ° C.Mokhoa oa phekolo oa matrix a li-slide ke o latelang: soak ka tharollo e nang le asiti (H2SO4/H2O2, 7/3Vol/VOL) bakeng sa 30min, ebe o hlatsoa ka metsi a hloekisitsoeng ka makhetlo a mangata ho fihlela pH e sa nke lehlakore, 'me qetellong e omme ka nitrogen e hloekileng.Kopano ea LBL e etsoa ka mochini o ikemetseng.Substrate e ne e kenngoa ka mokhoa o fapaneng ka tharollo ea CE (0.2 mg / mL) le tharollo ea PAA (0.2 mg / mL), tharollo e 'ngoe le e' ngoe e ne e kolobisitsoe ka metsotso e 4.Likoloi tse tharo tsa rinse tsa 1 min e 'ngoe le e' ngoe ka metsing a hloekisitsoeng li ne li etsoa pakeng tsa tharollo e 'ngoe le e' ngoe ho tlosa polymer e sa tsitsang.Litekanyetso tsa pH tsa tharollo ea kopano le tharollo ea ho rinse ka bobeli li fetotsoe ho pH 2.0.Lifilimi tse lokiselitsoeng li hlalosoa e le (CE/PAA) n, moo n e bolelang potoloho ea kopano.(HEC/PAA)40, (MC/PAA)30 le (HPC/PAA)30 li ne li lokisitsoe haholo-holo.
Sebopeho sa lifilimi:
Ho ile ha tlalehoa le ho hlahlobisisoa pono e haufi le e tloaelehileng ea ho bonahatsa lintho ka NanoCalc-XR Ocean Optics, 'me botenya ba lifilimi tse behiloeng holim'a silicon bo ile ba lekanngoa.Ka silicon substrate e se nang letho joalo ka bokamorao, ponahalo ea FT-IR ea filimi e tšesaane e holim'a silicon substrate e ile ea bokelloa ho Nicolet 8700 infrared spectrometer.
Litšebelisano tsa hydrogen bond lipakeng tsa PAA le CEs:
Kopano ea HEC, MC le HPC le PAA ho etsa lifilimi tsa LBL.Sebopeho sa infrared sa HEC/PAA, MC/PAA le HPC/PAA se bontšitsoe setšoantšong.Matšoao a matla a IR a PAA le CES a ka bonoa ka ho hlaka ho IR spectra ea HEC/PAA, MC/PAA le HPC/PAA.FT-IR spectroscopy e ka hlahloba ho kopanngoa ha hydrogen bond pakeng tsa PAA le CES ka ho beha leihlo ho fetoha ha lihlopha tsa ho monya.Maqhama a haedrojene pakeng tsa CES le PAA haholo-holo a hlaha pakeng tsa oksijene ea hydroxyl ea CES le sehlopha sa COOH sa PAA.Ka mor'a hore hydrogen bond e thehoe, tlhōrō e otlolohileng e khubelu e fetela ho tataiso e tlaase ea maqhubu.
Tlhōrō ea 1710 cm-1 e ile ea hlokomeloa bakeng sa phofo e hloekileng ea PAA.Ha polyacrylamide e ne e bokelloa lifiliming tse nang le li-CE tse fapaneng, litlhōrō tsa lifilimi tsa HEC/PAA, MC/PAA le MPC/PAA li ne li fumaneha ho 1718 cm-1, 1720 cm-1 le 1724 cm-1, ka ho latellana.Ha ho bapisoa le phofo e hloekileng ea PAA, bolelele ba tlhōrō ea lifilimi tsa HPC / PAA, MC / PAA le HEC / PAA li fetotsoe ke 14, 10 le 8 cm-1, ka ho latellana.Bond ea hydrogen pakeng tsa oksijene ea ether le COOH e sitisa tlamahano ea hydrogen pakeng tsa lihlopha tsa COOH.Ha maqhama a haedrojene a ntse a eketseha pakeng tsa PAA le CE, ke moo phetoho e kholo ea CE/PAA ho IR spectra.HPC e na le tekanyo e phahameng ka ho fetisisa ea hydrogen bond complexation, PAA le MC li bohareng, 'me HEC e tlaase ka ho fetisisa.
Boitšoaro ba kholo ea lifilimi tse kopaneng tsa PAA le CEs:
Boitšoaro ba ho etsa lifilimi ba PAA le CE nakong ea kopano ea LBL bo ile ba fuputsoa ho sebelisoa QCM le spectral interferometry.QCM e sebetsa hantle bakeng sa ho lekola kholo ea lifilimi sebakeng sa lipotoloho tse 'maloa tsa pele tsa likopano.Li-interferometer tsa Spectral li loketse lifilimi tse holisitsoeng ho feta li-cycle tse 10.
Filimi ea HEC / PAA e bonts'itse kholo ea mola ho pholletsa le ts'ebetso ea kopano ea LBL, ha lifilimi tsa MC / PAA le HPC / PAA li bonts'a kholo e kholo methating ea pele ea kopano ebe e fetoloa kholo ea mola.Sebakeng sa kholo ea mela, ha tekanyo ea ho rarahana e phahame, kholo ea botenya ka potoloho ea kopano.
Phello ea tharollo pH kholong ea filimi:
Boleng ba pH ba tharollo bo ama kholo ea hydrogen bonded polymer composite filimi.Joaloka polyelectrolyte e fokolang, PAA e tla behoa ionized le ho qosoa hampe ha pH ea tharollo e ntse e eketseha, kahoo e thibela mokhatlo oa hydrogen bond.Ha tekanyo ea ionization ea PAA e fihla boemong bo itseng, PAA e ne e sitoa ho bokana ka filimi e nang le li-receptors tsa hydrogen bond ho LBL.
Botenya ba filimi bo fokotsehile ka ho eketseha ha tharollo pH, 'me botenya ba filimi bo fokotsehile ka tšohanyetso ho pH2.5 HPC/PAA le pH3.0-3.5 HPC/PAA.Ntlha ea bohlokoa ea HPC/PAA e ka bang pH 3.5, ha ea HEC/PAA e ka ba 3.0.Sena se bolela hore ha pH ea tharollo ea kopano e phahame ho feta 3.5, filimi ea HPC / PAA e ke ke ea thehoa, 'me ha pH ea tharollo e phahame ho feta 3.0, filimi ea HEC / PAA e ke ke ea thehoa.Ka lebaka la tekanyo e phahameng ea motsoako oa hydrogen bond ea membrane ea HPC / PAA, bohlokoa ba pH ba lesela la HPC/PAA bo phahame ho feta ba lesela la HEC/PAA.Ka tharollo e se nang letsoai, litekanyetso tsa bohlokoa tsa pH tsa li-complexes tse entsoeng ke HEC / PAA, MC / PAA le HPC / PAA li ne li ka ba 2.9, 3.2 le 3.7, ka ho latellana.PH ea bohlokoa ea HPC/PAA e phahame ho feta ea HEC/PAA, e tsamaellanang le ea LBL membrane.
Ts'ebetso ea ho monya metsi ea lesela la CE / PAA:
CES e ruile ka lihlopha tsa hydroxyl hoo e nang le ho monya metsi hantle le ho boloka metsi.Ho nka lesela la HEC/PAA e le mohlala, matla a adsorption a hydrogen-bonded CE/PAA membrane ho metsi tikolohong e ile ea ithutoa.E khetholloa ke spectral interferometry, botenya ba filimi bo eketseha ha filimi e monya metsi.E ile ea behoa sebakeng se nang le mongobo o feto-fetohang ho 25 ° C bakeng sa lihora tse 24 ho finyella tekano ea ho monya metsi.Lifilimi li omisitsoe ka ontong ea vacuum (40 ° C) bakeng sa 24 h ho tlosa mongobo ka ho feletseng.
Ha mongobo o ntse o eketseha, filimi e teteaneng.Sebakeng sa mongobo o tlase oa 30% -50%, kholo ea botenya e batla e lieha.Ha mongobo o feta 50%, botenya bo hola ka potlako.Ha ho bapisoa le lesela la hydrogen-bonded PVPON/PAA, lesela la HEC/PAA le ka monya metsi a mangata ho tsoa tikolohong.Tlas'a boemo ba mongobo o lekanyelitsoeng oa 70% (25 ° C), mefuta e teteaneng ea filimi ea PVPON/PAA e ka bang 4%, ha filimi ea HEC/PAA e phahame hoo e ka bang 18%.Liphello li bontšitse hore le hoja palo e itseng ea lihlopha tsa OH tsamaisong ea HEC / PAA e kentse letsoho ho thehoeng ha li-hydrogen bond, ho ne ho ntse ho e-na le palo e kholo ea lihlopha tsa OH tse sebelisanang le metsi tikolohong.Ka hona, sistimi ea HEC/PAA e na le thepa e ntle ea ho monya metsi.
ha re phethela
(1) Tsamaiso ea HPC / PAA e nang le tekanyo e phahameng ka ho fetisisa ea hydrogen bonding ea CE le PAA e na le khōlo e potlakileng har'a bona, MC / PAA e bohareng, 'me HEC / PAA e tlaase ka ho fetisisa.
(2) Filimi ea HEC / PAA e bontšitse mokhoa oa ho hōla ka mokhoa o lekaneng nakong eohle ea ho itokisa, ha lifilimi tse ling tse peli MC / PAA le HPC / PAA li bonts'a khōlo e kholo ea lipotoloho tse seng kae tsa pele, ebe li fetoloa mokhoa oa ho hōla ka mela.
(3) Khōlo ea filimi ea CE / PAA e itšetlehile haholo ka tharollo ea pH.Ha tharollo ea pH e phahame ho feta ntlha ea eona ea bohlokoa, PAA le CE li ke ke tsa kopana ka filimi.Lera le kopaneng la CE/PAA le ne le qhibiliha ka tharollo e phahameng ea pH.
(4) Kaha filimi ea CE / PAA e ruile ho OH le COOH, phekolo ea mocheso e etsa hore e kopane.Lera la CE/PAA le amanang le sefapano le na le botsitso bo botle 'me ha le qhibilihe ka tharollo e phahameng ea pH.
(5) Filimi ea CE / PAA e na le bokhoni bo botle ba adsorption bakeng sa metsi tikolohong.
Nako ea poso: Feb-18-2023