Zvekutsvagisa
Sechisikigo, chakawanda uye chinogonekazve, cellulose inosangana nematambudziko makuru mumashandisirwo anoshanda nekuda kwekusanyungudika kwayo uye kushomeka kunyungudika. Iyo yakakwira crystallinity uye yakakwirira-density hydrogen zvisungo mune cellulose chimiro inoita kuti ideredze asi isinganyungudike panguva yekutora, uye isinganyungudika mumvura uye yakawanda organic solvents. Mamiriro avo anogadzirwa ne esterification uye etherification yemapoka ehydroxyl pane anhydroglucose mayunitsi mu polymer cheni, uye acharatidza zvimwe zvakasiyana zvivakwa zvichienzaniswa neakasikwa cellulose. Iyo etherification reaction ye cellulose inogona kugadzira akawanda-soluble cellulose ethers emvura, akadai semethyl cellulose (MC), hydroxyethyl cellulose (HEC) uye hydroxypropyl cellulose (HPC), iyo inoshandiswa zvakanyanya mukudya, zvizorwa, mumishonga nemishonga. Mvura-inonyungudika CE inogona kuumba hydrogen-bonded mapolymers ane polycarboxylic acids uye polyphenols.
Layer-by-layer assembly (LBL) inzira inoshanda yekugadzira mapolymer composite mafirimu matete. Izvi zvinotevera zvinonyanya kutsanangura gungano reLBL remaCE matatu akasiyana eHEC, MC neHPC nePAA, inoenzanisa maitiro egungano ravo, uye inoongorora pesvedzero yevanotsiva pagungano reLBL. Ongorora maitiro epH pakukora kwemafirimu, uye mutsauko wakasiyana wepH pakugadzira firimu uye kunyungudika, uye gadzira zvimiro zvekutora mvura zveEC/PAA.
Kuedza zvinhu:
Polyacrylic acid (PAA, Mw = 450,000). Iyo viscosity ye2wt.% aqueous solution yehydroxyethylcellulose (HEC) i300 mPa · s, uye dhigirii yekutsiva i2.5. Methylcellulose (MC, 2wt.% aqueous solution ine viscosity ye400 mPa · s uye dhigirii yekutsiva 1.8). Hydroxypropyl cellulose (HPC, 2wt.% aqueous solution ine viscosity ye 400 mPa · dhigirii yekutsiva 2.5).
Kugadzirira kwefirimu:
Yakagadzirirwa ne liquid crystal layer assembly pasilicon pa25°C. Nzira yekurapa yematrix yemasiraidhi ndeiyi: soak in acidic solution (H2SO4/H2O2, 7/3Vol/VOL) for 30min, wozogeza nemvura ine deionized kakawanda kusvika pH yave isina kwayakarerekera, uye pakupedzisira yakaoma nenitrogen yakachena. LBL musangano unoitwa uchishandisa otomatiki muchina. Iyo substrate yakasvibiswa yakanyoroveswa muEC solution (0.2 mg / mL) uye PAA solution (0.2 mg / mL), mhinduro imwe neimwe yakanyoroveswa 4 min. Zvitatu zvekugezesa zvinyoro zve 1 min imwe neimwe mumvura yakasvibiswa yakaitwa pakati pemhinduro yega yega soak kuti ibvise yakasununguka yakanamirwa polymer. Huwandu hwepH hwemushonga wegungano uye mushonga wekusuka zvese zvakagadziridzwa kuita pH 2.0. Iwo mafirimu-akagadzirirwa anotsanangurwa se (CE/PAA) n, apo n inoreva kutenderera kwegungano. (HEC/PAA)40, (MC/PAA)30 uye (HPC/PAA)30 yainyanya kugadzirirwa.
Kuita Mafirimu:
Pedyo-yakajairika reflectance spectra yakarekodhwa uye yakaongororwa neNanoCalc-XR Ocean Optics, uye ukobvu hwemafirimu akaiswa pasilicon akayerwa. Iine isina silicon substrate semashure, iyo FT-IR spectrum yefirimu rakatetepa pasilicon substrate yakaunganidzwa paNicolet 8700 infrared spectrometer.
Hydrogen bond kudyidzana pakati pePAA neECs:
Gungano reHEC, MC uye HPC nePAA mumafirimu eLBL. Iyo infrared spectra yeHEC/PAA, MC/PAA uye HPC/PAA inoratidzwa mumufananidzo. Izvo zvakasimba IR zviratidzo zvePAA neCES zvinogona kunyatsoonekwa muIR spectra yeHEC/PAA, MC/PAA uye HPC/PAA. FT-IR spectroscopy inogona kuongorora iyo hydrogen bond yakaoma pakati pePAA neCES nekutarisa kuchinjika kwemabhendi ekunyudza. Iyo hydrogen bonding pakati peCES nePAA inonyanya kuitika pakati peiyo hydroxyl oxygen yeCES neCOOH boka rePAA. Mushure mekunge hydrogen bond yaumbwa, iyo inotambanudza peak tsvuku inoshanduka kune yakaderera frequency direction.
Nhamba yepamusoro ye1710 cm-1 yakaonekwa kune yakachena PAA powder. Pakaunganidzwa polyacrylamide kuita mafirimu ane maEC akasiyana, nhongonya dzeHEC/PAA, MC/PAA uye MPC/PAA mafirimu aive pa1718 cm-1, 1720 cm-1 uye 1724 cm-1, zvichiteerana. Kuenzaniswa neakachena PAA powder, kureba kwepamusoro kweHPC / PAA, MC / PAA uye HEC / PAA mafirimu akachinjwa ne14, 10 uye 8 cm-1, maererano. Chisungo chehydrogen pakati peether okisijeni neCOOH chinokanganisa chisungo chehydrogen pakati pemapoka eCOOH. Iyo yakawanda yehydrogen zvisungo inoumbwa pakati pePAA neEC, iyo yakakura shanduko yepamusoro yeEC/PAA muIR spectra. HPC ine dhigirii repamusoro rehydrogen bond complexation, PAA neMC zviri pakati, uye HEC ndiyo yakaderera.
Kukura maitiro emafirimu akasanganiswa ePAA neECs:
Maitiro ekugadzira firimu ePAA neEC panguva yegungano reLBL akaongororwa pachishandiswa QCM uye spectral interferometry. QCM inoshanda pakutarisa kukura kwemufirimu mu situ mukati mekutanga mashoma egungano kutenderera. Spectral interferometers inokodzera mafirimu akakura pamusoro pegumi.
Firimu reHEC/PAA rakaratidza kukura kwemutsara mukati memusangano weLBL, ukuwo MC/PAA neHPC/PAA mafirimu airatidza kukura kwakakura mumatanho ekutanga egungano ndokuzoshandurwa kuita mutsara wekukura. Munharaunda yekukura kwemutsara, iyo yakakwira dhigirii yekuomarara, ndiko kukura kwekukora pachikamu chegungano.
Mhedzisiro yemhinduro pH pakukura kwemafirimu:
Iyo pH kukosha kwemhinduro inokanganisa kukura kweiyo hydrogen bonded polymer composite film. Sezvo isina kusimba polyelectrolyte, PAA ichave ionized uye yakaipa mhosva sezvo pH yemhinduro inowedzera, nokudaro inhibiting hydrogen bond association. Pakasvika dhigirii reionization yePAA pane imwe nhanho, PAA haina kukwanisa kuungana kuita firimu rine mahydrogen bond anogamuchira muLBL.
Ukobvu hwefirimu hwakadzikira nekuwedzera kwemhinduro pH, uye ukobvu hwefirimu hwakadzikira kamwe kamwe papH2.5 HPC/PAA uye pH3.0-3.5 HPC/PAA. Iyo yakakosha poindi yeHPC/PAA inenge pH 3.5, nepo iyo yeHEC/PAA inenge 3.0. Izvi zvinoreva kuti kana pH yegadziriro yegungano yakakwirira kudarika 3.5, firimu yeHPC / PAA haigoni kuumbwa, uye kana pH yemhinduro yakakwirira kudarika 3.0, HEC / PAA firimu haigoni kuumbwa. Nekuda kweiyo yepamusoro dhigirii yehydrogen bond yakaoma yeHPC/PAA membrane, yakakosha pH kukosha kweHPC/PAA membrane yakakwirira kupfuura yeHEC/PAA membrane. Mune mhinduro isina munyu, iyo yakakosha pH kukosha kweiyo yakaoma yakaumbwa neHEC/PAA, MC/PAA uye HPC/PAA yaive inenge 2.9, 3.2 uye 3.7, zvichiteerana. Iyo yakaoma pH yeHPC/PAA yakakwirira kupfuura iyo yeHEC/PAA, inopindirana neiyo LBL membrane.
Kunyura kwemvura kuita kweEC / PAA membrane:
CES yakapfuma mumapoka ehydroxyl kuitira kuti ive nekutora mvura kwakanaka uye kuchengetedza mvura. Kutora HEC / PAA membrane semuenzaniso, iyo adsorption simba rehydrogen-bonded CE / PAA membrane kumvura munharaunda yakadzidzwa. Inoratidzwa ne spectral interferometry, iyo firimu ukobvu inowedzera sezvo firimu rinotora mvura. Yakaiswa munzvimbo ine humidity inogadziriswa pa 25 ° C kwemaawa makumi maviri nemana kuti iwane kuenzana kwemvura. Mafirimu akaomeswa muvheni yevacuum (40 ° C) kwe24 h kuti abvise zvachose unyoro.
Sezvo hunyoro hunowedzera, firimu rinowedzera. Munzvimbo yakaderera yehunyoro ye30% -50%, kukura kwekobvu kunononoka. Kana hunyoro hunopfuura 50%, ukobvu hunokura nekukurumidza. Kuenzaniswa nehydrogen-bonded PVPON/PAA membrane, HEC/PAA membrane inogona kutora mvura yakawanda kubva kunharaunda. Pasi pemamiriro ekunyorova kwe70% (25 ° C), kukora kwefirimu rePVPON/PAA kunosvika 4%, nepo HEC/PAA firimu rakakwirira kusvika 18%. Zvigumisiro zvakaratidza kuti kunyange zvazvo mamwe mapoka eOH ari muHEC/PAA system akabatanidzwa mukuumbwa kwehydrogen bonds, pakanga pachine nhamba yakawanda yemapoka eOH aipindirana nemvura munzvimbo. Naizvozvo, iyo HEC/PAA system ine yakanaka yekunyudza mvura zvivakwa.
mukupedzisa
(1) Iyo HPC/PAA system ine yakanyanya hydrogen bonding degree yeEC uye PAA ine kukurumidza kukura pakati pavo, MC/PAA iri pakati, uye HEC/PAA ndiyo yakaderera.
(2) Iyo HEC / PAA firimu yakaratidza mutsara wekukura modhi mukati megadziriro yekugadzirira, nepo mamwe mafirimu maviri MC/PAA neHPC/PAA airatidza kukura kwakanyanyisa mumitsetse mishoma yekutanga, ndokuzoshandurwa kuita mutsara wekukura modhi.
(3) Kukura kwemufirimu weEC / PAA kune kutsamira kwakasimba pane mhinduro pH. Kana iyo mhinduro pH yakakwira kupfuura iyo yakakosha point, PAA neEC haigone kuungana mufirimu. Iyo yakasanganiswa CE / PAA membrane yaive yakanyungudika mune yakakwirira pH mhinduro.
(4) Sezvo firimu reCE / PAA rakapfuma muOH uye COOH, kurapwa kwekupisa kunoita kuti ive yakabatana. Iyo muchinjiko-yakabatana CE/PAA membrane ine kugadzikana kwakanaka uye isinganyunguke mune yakakwirira pH mhinduro.
(5) Iyo CE / PAA firimu ine yakanaka adsorption kugona kwemvura munzvimbo.
Nguva yekutumira: Feb-18-2023