Poly （methyl methacrylate） （PMMA） brushes were synthesized from silicon wafers via surface initiated atom transfer radical polymerization （SI-ATRP）. Energy disperse spectroscopy （EDS） and atomic force microsco...Poly （methyl methacrylate） （PMMA） brushes were synthesized from silicon wafers via surface initiated atom transfer radical polymerization （SI-ATRP）. Energy disperse spectroscopy （EDS） and atomic force microscopy （AFM） confirmed that PMMA brushes were successfully prepared on the silicon wafers, and the surface became more hydrophobic according to the contact angle of 69~. It is found that CuCI/1, 1, 4, 7, 10, 10-hexamethyl triethylenetetramine （HMTETA） system is more suitable than CuBr/N, N, N′, N″, N′″-pentamethyl diethylenetriamine （PMDETA） system to control the free radical polymerization of MMA in solution. Nevertheless, better control on the thickness of PMMA brushes was achieved in CuBr/PMDETA than in CuC1/HMTETA due to higher activity and better reversibility of the former system.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
基金Project(21376271)supported by the National Natural Science Foundation of ChinaProject(2013)supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,China+2 种基金Projects(CL12129,201310533008)supported by the Undergraduates Innovative Training Foundation of Central South University,ChinaProject(Z12060)supported by the Undergraduate Free Exploration Innovation Foundation of Central South University,ChinaProject(CSUZC2013008)supported by the Open-End Fund for the Valuable and Precision Instruments of Central South University,China
文摘Poly （methyl methacrylate） （PMMA） brushes were synthesized from silicon wafers via surface initiated atom transfer radical polymerization （SI-ATRP）. Energy disperse spectroscopy （EDS） and atomic force microscopy （AFM） confirmed that PMMA brushes were successfully prepared on the silicon wafers, and the surface became more hydrophobic according to the contact angle of 69~. It is found that CuCI/1, 1, 4, 7, 10, 10-hexamethyl triethylenetetramine （HMTETA） system is more suitable than CuBr/N, N, N′, N″, N′″-pentamethyl diethylenetriamine （PMDETA） system to control the free radical polymerization of MMA in solution. Nevertheless, better control on the thickness of PMMA brushes was achieved in CuBr/PMDETA than in CuC1/HMTETA due to higher activity and better reversibility of the former system.
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.
