Functional and surface-active membranes from poly(vinylidene fluoride)-graft-poly(acrylic acid) prepared via RAFT-mediated graft copolymerization
Functional and surface-active membranes from poly(vinylidene fluoride)-graft-poly(acrylic acid) prepared via RAFT-mediated graft copolymerization
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DOI：
10.1021/la049383v
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发表时间：
2004-07-06
期刊：
影响因子：
3.9
通讯作者：
Neoh, KG
中科院分区：
文献类型：
--
作者：
Ying, L;Yu, WH;Neoh, KG
以臭氧预处理的聚偏氟乙烯（PVDF）与丙烯酸（AAc）为原料，采用加成-断裂链转移（RAFT）介导的可逆接枝共聚法制备了具有“活”聚丙烯酸（PAAc）侧链的聚偏氟乙烯（PVDF-g-PAAc）。通过元素分析、傅立叶红外光谱和热重分析对共聚物的化学组成和结构进行了表征。该共聚物可以在水介质中通过相转化很容易地浇铸到表面（包括孔表面）富含活性PAAc接枝链的ph敏感微滤（MF）膜中。用x射线光电子能谱法测定了膜的表面组成。用扫描电镜对膜的形貌进行了表征。该膜的孔径分布比传统自由基接枝共聚法制备的PVDF-g-PAAc膜均匀得多。最重要的是，通过与n -异丙基丙烯酰胺（NIPAAM）的表面引发嵌段共聚，具有表面拴系PAAc宏观链转移剂的MF膜或活膜表面可以进一步功能化，得到PVDF-g-PAAc-b-PNIPAAM MF膜，该膜对水介质具有pH和温度依赖的渗透性。
Poly(vinylidene fluoride) (PVDF) with "living" poly(acrylic acid) (PAAc) side chains (PVDF-g-PAAc) was prepared by reversible addition-fragmentation chain transfer (RAFT)-mediated graft copolymerization of acrylic acid (AAc) with the ozone-pretreated PVDF. The chemical composition and structure of the copolymers were characterized by elemental analysis, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The copolymer could be readily cast into pH-sensitive microfiltration (MF) membranes with enriched living PAAc graft chains on the surface (including the pore surfaces) by phase inversion in an aqueous medium. The surface composition of the membranes was determined by X-ray photoelectron spectroscopy. The morphology of the membranes was characterized by scanning electron microscopy. The pore size distribution of the membranes was found to be much more uniform than that of the corresponding membranes cast from PVDF-g-PAAc prepared by the "conventional" free-radical graft copolymerization process. Most important of all, the MF membranes with surface-tethered PAAc macro chain transfer agents, or the living membrane surfaces, could be further functionalized via surface-initiated block copolymerization with N-isopropylacrylamide (NIPAAM) to obtain the PVDF-g-PAAc-b-PNIPAAM MF membranes, which exhibited both pH- and temperature-dependent permeability to aqueous media.