The effect of substrate on the phase morphologies of PMMA/PS blend films was investigated by means of phase contrast microscope. PMMA/PS blend films were cast onto various substrates(such as glass substrate and PP sub...The effect of substrate on the phase morphologies of PMMA/PS blend films was investigated by means of phase contrast microscope. PMMA/PS blend films were cast onto various substrates(such as glass substrate and PP substrate) by spin-coating with thickness of about 10 μm. It was observed that there was a large difference of the phase inversion region between the blend films cast on glass and on PP substrates. On glass substrate, the phase inversion occurred at about \%Φ\%_m=0 4(PS mass fraction) while at \%Φ\%_m=0 5 on PP substrate. This implies that there is a shift of the phase inversion region with the change of substrate in cast polymer blend films. In other words, phase inversion region depends on the substrate. ATR-FTIR analysis was used to detect the composition of the surface and the bottom of the films(about 100 μm thick) obtained by evaporating solvent from the polymer blend solution. The ATR-FTIR spectra of the surface and the bottom of the PMMA/PS blend thin films cast on glass substrate and PP substrate showed that PMMA component preferentially segregated to glass substrate and PS component was enriched on the PP substrate. This selective segregation was due to the difference of the wetting abilities of PS and PMMA on the two kinds of substrates. The polymer-substrate interfacial tension γ were calculated and the results supported the ATR-FTIR results. It could be inferred that the shift of the phase inversion region with the change of the substrate in PMMA/PS blend film was due to the fact that the composition of the blend in the bulk changed, owing to the selective enrichment of one component of polymer blend to the substrate. In other words, the affinity between polymer and substrate can strongly influence the phase morphologies and the phase inversion region in polymer blend films.展开更多
Thin films of poly(methyl methacrylate)/polystyrene (PMMA/PS 80/20 W/W) blend prepared on glass substrate by spin-coating from a cosolvent, chloroform were studied. The formation of regular Voronoi patterns was found ...Thin films of poly(methyl methacrylate)/polystyrene (PMMA/PS 80/20 W/W) blend prepared on glass substrate by spin-coating from a cosolvent, chloroform were studied. The formation of regular Voronoi patterns was found under phase contrast microscopy (PCM). It was observed that there were clear concave boundaries in the PCM images by atomic force microscopy (AFM). Although the sample was annealed at 220℃ more than 7 h, no changes of the Voronoi pattern occurred, implying that the phase separation structure in the Voronoi pattern was almost complete during spin-coating process. It was believed that the formation of this pattern was due to the convection during spin-coating procedure.展开更多
To obtain water-insoluble silk fibroin(SF) materials, polyethylene glycol diglycidyl ether(PEG-DE) was selected as a crosslinking agent to prepare SF films(blends). The reaction conditions were optimized for the cross...To obtain water-insoluble silk fibroin(SF) materials, polyethylene glycol diglycidyl ether(PEG-DE) was selected as a crosslinking agent to prepare SF films(blends). The reaction conditions were optimized for the crosslinking of the SF molecules. The hot water stability of the blends was measured using BCA protein assay and gravimetric analysis. The molecular conformation and crystalline structure of the blends were analyzed by FTIR and XRD, respectively. When the mass ratio of SF:PEG-DE was 1.0:0.8, the hot water loss rate of the SF blends was minimized. PEG-DE could induce SF molecules to form β-sheets during the gel reaction process, resulting in improved crystallinity and hot water dissolved resistance of the blend films. In order to demonstrate the cytotoxicity of the chemical reagents used to crosslink SF, L929 cells were seeded on the blend film(SF:PEG-DE = 1:1) and cultured for 3 days. Cells of L929 readily adhered and spread in the fusiform on the blend film resulting in high cell viability. The extracted liquid from the SF porous film did not inhibit cell proliferation, as estimated by the MTT assay.展开更多
The blend films with gelatin and poly(vinyl alcohol)(PVA) were prepared by a solution casting method. The compatibility between gelatin and PVA in the blend films was investigated. The transmittance, Fourier-transform...The blend films with gelatin and poly(vinyl alcohol)(PVA) were prepared by a solution casting method. The compatibility between gelatin and PVA in the blend films was investigated. The transmittance, Fourier-transform infrared spectroscopy(FTIR), x-ray diffraction(XRD), thermogravimetry analysis(TG), and differential scanning calorimetry(DSC) were employed to characterize the resultant blend films. According to optic result, the opacity of the blend film at the ratio of 20/80(w/w, Gel to PVA) was the lowest, indicating the best compatibility between Gel and PVA at the ratio. The results of IR, XRD, DSC, and TG revealed an intensive interaction and good compatibility between them in the blend film at the ratio. The mechanical properties and solubility showed that PVA content in the blend films obviously affected the elongation at break and solubility. The mechanical properties and water resistance of gelatin film may be improved by the introduction of PVA.展开更多
Deviations from bulk morphologies in thin films of binary blends of alkyne-functionalized diblock copolymer poly(ethylene oxide)-block-poly(n-butyl methacrylate-random-propargyl methacrylate) (PEO-b-P(nBMA-r-PgMA)) an...Deviations from bulk morphologies in thin films of binary blends of alkyne-functionalized diblock copolymer poly(ethylene oxide)-block-poly(n-butyl methacrylate-random-propargyl methacrylate) (PEO-b-P(nBMA-r-PgMA)) and Rhodamine B azide are reported, where thermal click reaction between the two components leads to microphase separated morphologies. Both in the bulk and in thin films, increasing the azide loading ratio resulted in the transition from a lamellar microdomain morphology to a hexagonally packed cylindrical mircodomain morphology. However, in thin films the lamellae-cylinder transition was observed at a different azide loading ratio, which was determined by film thickness. As a result, significant deviations from the bulk morphology were observed. These results indicate that surface interactions and confined geometry can play an important role in dictating the morphology in thin films of BCP/additive binary blends.展开更多
Thin films of polymer blends composed of alternating copolymer, diblock copolymer and/or homopolymer are studied using Monte Carlo simulation. A multilayer morphology is observed in the film, that is, the blended poly...Thin films of polymer blends composed of alternating copolymer, diblock copolymer and/or homopolymer are studied using Monte Carlo simulation. A multilayer morphology is observed in the film, that is, the blended polymers assemble into individual domains arranged from interior to the surfaces of the film. The coexisting components residing throughout the neighboring domains in the film make no distinguishable interface between any neighboring domains. By this means, it forms a vertical composition gradient in the polymeric film. Being different from layer-by-layer deposition of polyelectrolyte or hydrogen bonding approach etc., the layered structure in this study is formed by polymer blending in one step. Alternating copolymers are found to be essential components to form vertical composition gradient(layered structure) in thin films.展开更多
文摘The effect of substrate on the phase morphologies of PMMA/PS blend films was investigated by means of phase contrast microscope. PMMA/PS blend films were cast onto various substrates(such as glass substrate and PP substrate) by spin-coating with thickness of about 10 μm. It was observed that there was a large difference of the phase inversion region between the blend films cast on glass and on PP substrates. On glass substrate, the phase inversion occurred at about \%Φ\%_m=0 4(PS mass fraction) while at \%Φ\%_m=0 5 on PP substrate. This implies that there is a shift of the phase inversion region with the change of substrate in cast polymer blend films. In other words, phase inversion region depends on the substrate. ATR-FTIR analysis was used to detect the composition of the surface and the bottom of the films(about 100 μm thick) obtained by evaporating solvent from the polymer blend solution. The ATR-FTIR spectra of the surface and the bottom of the PMMA/PS blend thin films cast on glass substrate and PP substrate showed that PMMA component preferentially segregated to glass substrate and PS component was enriched on the PP substrate. This selective segregation was due to the difference of the wetting abilities of PS and PMMA on the two kinds of substrates. The polymer-substrate interfacial tension γ were calculated and the results supported the ATR-FTIR results. It could be inferred that the shift of the phase inversion region with the change of the substrate in PMMA/PS blend film was due to the fact that the composition of the blend in the bulk changed, owing to the selective enrichment of one component of polymer blend to the substrate. In other words, the affinity between polymer and substrate can strongly influence the phase morphologies and the phase inversion region in polymer blend films.
文摘Thin films of poly(methyl methacrylate)/polystyrene (PMMA/PS 80/20 W/W) blend prepared on glass substrate by spin-coating from a cosolvent, chloroform were studied. The formation of regular Voronoi patterns was found under phase contrast microscopy (PCM). It was observed that there were clear concave boundaries in the PCM images by atomic force microscopy (AFM). Although the sample was annealed at 220℃ more than 7 h, no changes of the Voronoi pattern occurred, implying that the phase separation structure in the Voronoi pattern was almost complete during spin-coating process. It was believed that the formation of this pattern was due to the convection during spin-coating procedure.
基金Funded by National Natural Science Foundation of China(Nos.51173125 and 51473108)Natural Science Foundation of Jiangsu Province of China(Nos.BK2012633 and BK2041210)+2 种基金College Natural Science Research Project of Jiangsu Province of China(No.12KJA43004)the Science and Technology Development Foundation of Suzhou of China(Nos.SYG201001 and SS201341)Priority Academic Program Development of Jiangsu Higher Education Institutions[PAPD]
文摘To obtain water-insoluble silk fibroin(SF) materials, polyethylene glycol diglycidyl ether(PEG-DE) was selected as a crosslinking agent to prepare SF films(blends). The reaction conditions were optimized for the crosslinking of the SF molecules. The hot water stability of the blends was measured using BCA protein assay and gravimetric analysis. The molecular conformation and crystalline structure of the blends were analyzed by FTIR and XRD, respectively. When the mass ratio of SF:PEG-DE was 1.0:0.8, the hot water loss rate of the SF blends was minimized. PEG-DE could induce SF molecules to form β-sheets during the gel reaction process, resulting in improved crystallinity and hot water dissolved resistance of the blend films. In order to demonstrate the cytotoxicity of the chemical reagents used to crosslink SF, L929 cells were seeded on the blend film(SF:PEG-DE = 1:1) and cultured for 3 days. Cells of L929 readily adhered and spread in the fusiform on the blend film resulting in high cell viability. The extracted liquid from the SF porous film did not inhibit cell proliferation, as estimated by the MTT assay.
基金Funded by the National Natural Science Foundation of China(Nos.21076199,51373158)
文摘The blend films with gelatin and poly(vinyl alcohol)(PVA) were prepared by a solution casting method. The compatibility between gelatin and PVA in the blend films was investigated. The transmittance, Fourier-transform infrared spectroscopy(FTIR), x-ray diffraction(XRD), thermogravimetry analysis(TG), and differential scanning calorimetry(DSC) were employed to characterize the resultant blend films. According to optic result, the opacity of the blend film at the ratio of 20/80(w/w, Gel to PVA) was the lowest, indicating the best compatibility between Gel and PVA at the ratio. The results of IR, XRD, DSC, and TG revealed an intensive interaction and good compatibility between them in the blend film at the ratio. The mechanical properties and solubility showed that PVA content in the blend films obviously affected the elongation at break and solubility. The mechanical properties and water resistance of gelatin film may be improved by the introduction of PVA.
基金supported by the Department of Energy Office of Basic Energy Science under Contract No. DE-FG02-96ER45612(XW, TPR design of experiments, synthesis of BCP)the NSF-supported Materials Research Science and Engineering Center and the NSF-supported Center for Hierarchical Manufacturing at University of Massachusetts Amherst(XS, WG, assistance with the GISAXS measurements)+1 种基金Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S.Department of Energy Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357Use of the Advanced Light Source is supported by the Director Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
文摘Deviations from bulk morphologies in thin films of binary blends of alkyne-functionalized diblock copolymer poly(ethylene oxide)-block-poly(n-butyl methacrylate-random-propargyl methacrylate) (PEO-b-P(nBMA-r-PgMA)) and Rhodamine B azide are reported, where thermal click reaction between the two components leads to microphase separated morphologies. Both in the bulk and in thin films, increasing the azide loading ratio resulted in the transition from a lamellar microdomain morphology to a hexagonally packed cylindrical mircodomain morphology. However, in thin films the lamellae-cylinder transition was observed at a different azide loading ratio, which was determined by film thickness. As a result, significant deviations from the bulk morphology were observed. These results indicate that surface interactions and confined geometry can play an important role in dictating the morphology in thin films of BCP/additive binary blends.
基金financially supported by the National Natural Science Foundation of China(Nos.20804001,20974001,21174001 and 51273001)the Research Fund for the Doctoral Program of Higher Education of China(20113401110003)+2 种基金the University Natural Science Research Project of Anhui Province(KJ2011z015)"211 Project""Incubation Fund for Excellent Young Researcher" of Anhui University
文摘Thin films of polymer blends composed of alternating copolymer, diblock copolymer and/or homopolymer are studied using Monte Carlo simulation. A multilayer morphology is observed in the film, that is, the blended polymers assemble into individual domains arranged from interior to the surfaces of the film. The coexisting components residing throughout the neighboring domains in the film make no distinguishable interface between any neighboring domains. By this means, it forms a vertical composition gradient in the polymeric film. Being different from layer-by-layer deposition of polyelectrolyte or hydrogen bonding approach etc., the layered structure in this study is formed by polymer blending in one step. Alternating copolymers are found to be essential components to form vertical composition gradient(layered structure) in thin films.
