In this study, commercial biaxially oriented polypropylene （BOPP）, polyvinyl chlo- ride （PVC） and poly （methyl methacrylate） （PMMA） films were treated with nitrogen plasma over different exposure times in a Py...In this study, commercial biaxially oriented polypropylene （BOPP）, polyvinyl chlo- ride （PVC） and poly （methyl methacrylate） （PMMA） films were treated with nitrogen plasma over different exposure times in a Pyrex tube surrounded by a DC variable magnetic field. The chemi- cal changes that appeared on the surface of the samples were investigated using Fourier transform infrared （FT4R） spectroscopy and attenuated total reflectance Fourier transform infrared （ATR- FTIR） spectroscopy after treatment for 2 min, 4 min and 6 rain in a nitrogen plasma chamber. Effects of the plasma treatment on the surface topographies and contact angles of the untreated and plasma treated films were also analyzed by atomic force microscopy （AFM） and a contact angle measuring system. The results show that the plasma treated films become more hydrophilic with an enhanced wettability due to the formation of some new polar groups on the surface of the treated films. Moreover, at higher exposure times, the total surface energy in all treated films increased while a reduction in contact angle occurred. The behavior of surface roughness in each sample was completely different at higher exposure times.展开更多
The photochemical kinetics of phenanthrenequinone （PQ） doped poly （methyl methacrylate） photopolymer in holographic recording was studied theoretically and experimentally. The diffusion of PQ molecules during holo...The photochemical kinetics of phenanthrenequinone （PQ） doped poly （methyl methacrylate） photopolymer in holographic recording was studied theoretically and experimentally. The diffusion of PQ molecules during holographic recording was negligible because of its small diffusion coefficient at room temperature. A photochemical reaction kinetics model of PQ/PMMA was established. The analytical expressions for the temporal variations of transmittance and diffraction efficiency were derived. By fitting the experimental curves, some parameters related with the polymer components were obtained by the proposed model, which can be used to analyze the photochemical process and will be helpful to the optimization of material preparation.展开更多
We proposed a novel method of fabricating polydimethylsiloxane (PDMS) microfluidic chip polymer master molds in this paper. The method mainly includes two steps. First, a stainless steel slice was laser etched to form...We proposed a novel method of fabricating polydimethylsiloxane (PDMS) microfluidic chip polymer master molds in this paper. The method mainly includes two steps. First, a stainless steel slice was laser etched to form a metal model. Then, the organic solution of poly(methyl methacrylate) (PMMA) was casted onto the metal model to fabricate the PMMA master which subsequently would be used to fabricate PDMS chips. We systematically researched different laser parameters influencing the surface status of microchannels and obtained optimized etching parameters. We investigated and optimized the organic solution composition of PMMA while casting chip masters, and developed a method to form fine polymer masters using two different viscosity solutions to cast the model in turn, and studied the repeatable replication. Then, we investigated physical performance of this chip and evaluated the practicability by analyzing Rhodamine B. Compared with present methods, the proposed method does not need photolithography on photoresistant and chemical etching. The entire fabricating progress is simple, fast, low-cost and can be controlled easily. Only several minutes are required to make a metal model, 3 hours for a PMMA master, and one day for PDMS chips.展开更多
Poly(methyl methacrylate)-titania hybrid glasses were synthesized by sol-gel processes using acrylic acid or allyl acetylacetone as coupling agent. Titanium butoxide modified with acrylic acid (or titanium isopropoxid...Poly(methyl methacrylate)-titania hybrid glasses were synthesized by sol-gel processes using acrylic acid or allyl acetylacetone as coupling agent. Titanium butoxide modified with acrylic acid (or titanium isopropoxide modified with allyl acetylacetone) was hydrolyzed to produce a titania network, and then poly(methyl methacrylate) (PMMA)chains formed in situ through a radical polymerization were chendcally bonded to the fortheng titania network to synthesize a hybrid glass. Transparent hybrid glasses with different contents of titania were achieved. With the increase of the titania content, the color of the products changed from yellow to red. The synthesis process was investigated stepwise by using FTIR spectroscopies, and the experimental results demonstrated that acrylic or acetylacetonate groups bound to titanium remain in the final hybrid glasses.The thermal stability of the hybrid materials were considerably improved relative to pure PMMA. The hybrid glasses using allyl acetylacetone as coupling agent exhibited ther mochromatic effect which both pure PMMA and titan ia do not manifest.展开更多
文摘In this study, commercial biaxially oriented polypropylene （BOPP）, polyvinyl chlo- ride （PVC） and poly （methyl methacrylate） （PMMA） films were treated with nitrogen plasma over different exposure times in a Pyrex tube surrounded by a DC variable magnetic field. The chemi- cal changes that appeared on the surface of the samples were investigated using Fourier transform infrared （FT4R） spectroscopy and attenuated total reflectance Fourier transform infrared （ATR- FTIR） spectroscopy after treatment for 2 min, 4 min and 6 rain in a nitrogen plasma chamber. Effects of the plasma treatment on the surface topographies and contact angles of the untreated and plasma treated films were also analyzed by atomic force microscopy （AFM） and a contact angle measuring system. The results show that the plasma treated films become more hydrophilic with an enhanced wettability due to the formation of some new polar groups on the surface of the treated films. Moreover, at higher exposure times, the total surface energy in all treated films increased while a reduction in contact angle occurred. The behavior of surface roughness in each sample was completely different at higher exposure times.
基金Project supported by the Fundamental Research Foundation of COSTIND (Grant No 2320060089)the MOST of China (973 Project Grant No 2007CB307001)Program of Excellent Team in Harbin Institute of Technology
文摘The photochemical kinetics of phenanthrenequinone （PQ） doped poly （methyl methacrylate） photopolymer in holographic recording was studied theoretically and experimentally. The diffusion of PQ molecules during holographic recording was negligible because of its small diffusion coefficient at room temperature. A photochemical reaction kinetics model of PQ/PMMA was established. The analytical expressions for the temporal variations of transmittance and diffraction efficiency were derived. By fitting the experimental curves, some parameters related with the polymer components were obtained by the proposed model, which can be used to analyze the photochemical process and will be helpful to the optimization of material preparation.
基金Funded by the Natural Science Foundation of China (No. 20775096)
文摘We proposed a novel method of fabricating polydimethylsiloxane (PDMS) microfluidic chip polymer master molds in this paper. The method mainly includes two steps. First, a stainless steel slice was laser etched to form a metal model. Then, the organic solution of poly(methyl methacrylate) (PMMA) was casted onto the metal model to fabricate the PMMA master which subsequently would be used to fabricate PDMS chips. We systematically researched different laser parameters influencing the surface status of microchannels and obtained optimized etching parameters. We investigated and optimized the organic solution composition of PMMA while casting chip masters, and developed a method to form fine polymer masters using two different viscosity solutions to cast the model in turn, and studied the repeatable replication. Then, we investigated physical performance of this chip and evaluated the practicability by analyzing Rhodamine B. Compared with present methods, the proposed method does not need photolithography on photoresistant and chemical etching. The entire fabricating progress is simple, fast, low-cost and can be controlled easily. Only several minutes are required to make a metal model, 3 hours for a PMMA master, and one day for PDMS chips.
文摘Poly(methyl methacrylate)-titania hybrid glasses were synthesized by sol-gel processes using acrylic acid or allyl acetylacetone as coupling agent. Titanium butoxide modified with acrylic acid (or titanium isopropoxide modified with allyl acetylacetone) was hydrolyzed to produce a titania network, and then poly(methyl methacrylate) (PMMA)chains formed in situ through a radical polymerization were chendcally bonded to the fortheng titania network to synthesize a hybrid glass. Transparent hybrid glasses with different contents of titania were achieved. With the increase of the titania content, the color of the products changed from yellow to red. The synthesis process was investigated stepwise by using FTIR spectroscopies, and the experimental results demonstrated that acrylic or acetylacetonate groups bound to titanium remain in the final hybrid glasses.The thermal stability of the hybrid materials were considerably improved relative to pure PMMA. The hybrid glasses using allyl acetylacetone as coupling agent exhibited ther mochromatic effect which both pure PMMA and titan ia do not manifest.
