Tuning the morphology, network structure, and degradation of thermo-sensitive microgels by controlled addition of degradable cross-linker
Tuning the morphology, network structure, and degradation of thermo-sensitive microgels by controlled addition of degradable cross-linker
复制标题
通过控制添加可降解交联剂来调节热敏微凝胶的形态、网络结构和降解
DOI：
10.1007/s00396-017-4056-2
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发表时间：
2017-04-01
影响因子：
2.4
通讯作者：
Du, Binyang
中科院分区：
文献类型：
--
作者：
Cui, Ruiguang;Zhang, Zhijun;Du, Binyang
以过硫酸钾（KPS）和N，N，N '，N'-四甲基乙二胺为氧化还原引发剂，在50 ℃下通过无皂乳液聚合制备了聚N-异丙基丙烯酰胺（PNIPAm）微凝胶。NIPAm、2-丙烯酰胺基-2-甲基-1-丙磺酸钠（AMPS-Na）和N，N ′-双（丙烯酰基）胱胺（BAC）分别作为主单体、阴离子共聚单体和可降解交联剂。结果表明，通过控制BAC和AMPS-Na的添加量，可以调控微凝胶的形貌和网络结构，进而影响微凝胶的热敏性、稳定性和降解行为。通过延长KPS引发和BAC加入之间的时间tBAC，可以改善微凝胶的非均匀网络结构。微凝胶的形貌由球形转变为中空的内部球形。通过控制共聚单体AMPSNa的加入，可以提高微凝胶在生理条件下的稳定性。微凝胶的降解程度随着tBAC的增加而增加。
Thermo-sensitive degradable poly(N-isopropylacrylamide) (PNIPAm)-based microgels were prepared by surfactant-free emulsion polymerization with a redox initiator pair of potassium persulfate (KPS) and N,N,N',N'-tetramethylethylenediamine at 50 degrees C. NIPAm, sodium 2-acrylamido-2-methyl-1-propanesulfonate (AMPS-Na), and N,N'-bis(acryloyl) cystamine (BAC) were used as main monomer, anionic comonomer, and degradable cross-linker, respectively. It was found that the morphology and network structure of the resultant microgels could be tuned via the controlled addition of BAC and AMPS-Na, which, in turn, strongly affected the corresponding thermo-sensitivity, stability, and degradation behavior of the microgels. The inhomogeneous network structures of the microgels could be improved by increasing the time period tBAC between KPS initiation and the addition of BAC. The morphology of microgels changed from spherical into hollow interior spherical morphology. The stability of the microgels in physiological condition could be enhanced by the controlled addition of comonomer AMPSNa. The extent of microgel degradation increased with increasing tBAC.