Sengupta Arijit, Vu Anh, Qian Xianghong, Wickramasinghe S Ranil
Ralph E Martin Department of Chemical Engineering, University of Arkansas, Fayettteville, AR 72701, USA.
Bhabha Atomic Research Centre, Radiochemistry Division, Mumbai 400085, India.
Membranes (Basel). 2021 May 4;11(5):340. doi: 10.3390/membranes11050340.
Ultrafiltration membranes, that respond to an external magnetic field and local temperature have been developed. Surface-initiated activator-generated electron transfer (AGET) atom transfer radical polymerization (ATRP) has been used to graft poly(N-isopropylacrylamide) (PNIPAm) from the surface of 300 kDa regenerated cellulose membranes. The polymerization initiator was selectively attached to the entire membrane surface, only the outer membrane surface or only the inner pore surface. A superparamagnetic nanoparticle was attached to the end of the polymer chain. The DI water flux as well as the flux and rejection of bovine serum albumin were investigated in the absence and presence of a 20 and 1000 Hz oscillating magnetic field. In an oscillating magnetic field, the tethered superparamagnetic nanoparticles can cause movement of the PNIPAm chains or induce heating. A 20 Hz magnetic field maximizes movement of the chains. A 1000 Hz magnetic field leads to greater induced heating. PNIPAm displays a lower critical solution temperature at 32 °C. Heating leads to collapse of the PNIPAm chains above their Lower Critical Solution Temperature (LCST). This work highlights the versatility of selectively grafting polymer chains containing a superparamagnetic nanoparticle from specific membrane locations. Depending on the frequency of the oscillating external magnetic field, membrane properties may be tuned.
已开发出对外部磁场和局部温度有响应的超滤膜。表面引发的活化剂产生电子转移（AGET）原子转移自由基聚合（ATRP）已被用于从300 kDa再生纤维素膜表面接枝聚（N-异丙基丙烯酰胺）（PNIPAm）。聚合引发剂被选择性地连接到整个膜表面、仅外膜表面或仅内膜孔表面。一个超顺磁性纳米颗粒被连接到聚合物链的末端。在不存在和存在20 Hz和1000 Hz振荡磁场的情况下，研究了去离子水通量以及牛血清白蛋白的通量和截留率。在振荡磁场中， tethered超顺磁性纳米颗粒可引起PNIPAm链的移动或诱导加热。20 Hz磁场使链的移动最大化。1000 Hz磁场导致更大的诱导加热。PNIPAm在32℃显示较低临界溶液温度。加热导致PNIPAm链在其低临界溶液温度（LCST）以上塌陷。这项工作突出了从特定膜位置选择性接枝含有超顺磁性纳米颗粒的聚合物链的多功能性。根据振荡外部磁场的频率，可以调节膜的性能。
