Hydrogen-bonded multilayers of thermoresponsive polymers
Hydrogen-bonded multilayers of thermoresponsive polymers
复制标题
DOI：
10.1021/ma0516891
复制
发表时间：
2005-12-13
期刊：
影响因子：
5.5
通讯作者：
Sukhishvili, SA
中科院分区：
文献类型：
--
作者：
Kharlampieva, E;Kozlovskaya, V;Sukhishvili, SA
中性温度响应聚合物，例如聚（N-乙烯基己内酰胺）（PVCL）和聚（乙烯基甲基醚）（PVME），包括在使用这些聚合物与聚乙烯的层-层交替吸附的薄膜中使用原位FTIR-ATR定量膜内吸附的聚合物的量和羧基的电离（通过衰减全反射的傅里叶变换红外光谱）。通过氢键相互作用提供的层间粘附力的强度由多层分解的临界pH值（pH（CR））和临界电离（α（CR））推断，其为pH（CR）6.2，α（CR）2%和pHCR 6.95。PMAA/PVME和PMAA/PVCL膜的α（CR）分别为30%。当沉积到多孔支撑膜上时，PMAA/PVME和PMAA/PVCL多层膜显示出染料渗透性的温度响应性变化。该转变发生在25至35摄氏度的宽温度范围内，反映了膜内包含的PVME和PVCL链的相分离的较低协同性。最后，PMAA/PVME和PMAA/PVCL自组装进行到颗粒基材上，生产胶囊，其有望作为温度响应容器用于受控递送应用。
Neutral temperature responsive polymers, such as poly(N-vinylcaprolactam) (PVCL) and poly(vinyl methyl ether) (PVME), were included in ultrathin films using layer-by-layer alternating adsorption of these polymers with poly(methacrylic acid) (PMAA) at low pH. The amounts of polymers adsorbed and ionization of carboxylic groups within a film were quantified using in situ FTIR-ATR (Fourier transform infrared spectroscopy by attenuated total reflection). The strength of interlayer adhesion provided through hydrogen-bonding interactions was inferred from the critical pH value (pH(CR)) and critical ionization (alpha(CR)) for multilayer decomposition which were pH(CR) 6.2, alpha(CR) 2% and pHCR 6.95. alpha(CR) 30% for PMAA/PVME and PMAA/PVCL films, respectively. When deposited onto porous support membranes, PMAA/PVME and PMAA/PVCL multilayers exhibited temperature-responsive changes in dye permeability. The transition occurred in a wide temperature range from 25 to 35 degrees C, reflecting lower cooperativity of the phase separation of PVME and PVCL chains included within the film. Finally, PMAA/PVME and PMAA/PVCL self-assembly was performed onto particulate substrates, producing capsules which hold promise as temperature-responsive containers for controlled delivery applications.