Stott Jonathan, Schneider Jörg J
Technische Universität Darmstadt, Fachbereich Chemie, Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Alarich-Weiss Str. 12, 64287 Darmstadt, Germany.
Nanoscience for life GmbH & Co. KG, Regerstr. 1, 65193 Wiesbaden, Germany.
Beilstein J Nanotechnol. 2020 Jun 17;11:938-951. doi: 10.3762/bjnano.11.78. eCollection 2020.
Surface functionalization of porous materials allows for the introduction of additional functionality coupled with high mechanical stability of functionalized inner pores. Herein, we investigate the surface-initiated ring-opening polymerization (SI-ROP) of phenylalanine--carboxyanhydride (PA-NCA) in porous alumina membranes (ALOX-membranes) with respect to different solvent mixtures (tetrahydrofuran (THF) and dichloromethane (DCM)). It was found that increasing the volume fraction of DCM leads to an increasing amount of fibrillar polymer structures within the porous ALOX-membrane. A three-dimensional fibrillar network with intrinsic porosity was formed in DCM, whereas in THF, a dense and smooth polypeptide film was observed. A post-treatment with a mixture of chloroform and dichloroacetic acid leads to rearrangement of the morphology of the grafted polymer films. The analysis by scanning electron microscopy (SEM), near-infrared spectroscopy (NIR) and contact angle measurements (CA) reveals a change in morphology of the grafted polymer films, which is due to the rearrangement of the secondary structure of the polypeptides. No significant loss of the surface-grafted polypeptides was determined by thermogravimetric (TG) measurements, which indicates that the change in morphology of the polymer films is solely a result of a conformational change of the surface-grafted polypeptides. Furthermore, adsorption of a test analyte (chloroanilic acid) was investigated with respect to different polymer functionalization schemes for reversed-phase solid phase extraction applications. The adsorption capability of the functionalized composite membrane was increased from 16.7% to 38.1% compared to the native ALOX-membrane.
多孔材料的表面功能化能够引入额外的功能，同时使功能化的内部孔隙具有较高的机械稳定性。在此，我们研究了在多孔氧化铝膜（ALOX膜）中，针对不同溶剂混合物（四氢呋喃（THF）和二氯甲烷（DCM）），苯丙氨酸 - 羧基酸酐（PA - NCA）的表面引发开环聚合反应（SI - ROP）。研究发现，增加DCM的体积分数会导致多孔ALOX膜内纤维状聚合物结构的数量增加。在DCM中形成了具有固有孔隙率的三维纤维状网络，而在THF中，则观察到致密且光滑的多肽膜。用氯仿和二氯乙酸的混合物进行后处理会导致接枝聚合物膜的形态发生重排。通过扫描电子显微镜（SEM）、近红外光谱（NIR）和接触角测量（CA）分析表明，接枝聚合物膜的形态发生了变化，这是由于多肽二级结构的重排所致。热重分析（TG）测量未确定表面接枝多肽有明显损失，这表明聚合物膜形态的变化仅仅是表面接枝多肽构象变化的结果。此外，针对反相固相萃取应用，研究了不同聚合物功能化方案对测试分析物（氯苯胺酸）的吸附情况。与天然ALOX膜相比，功能化复合膜的吸附能力从16.7%提高到了38.1%。
