Stoica Iuliana, Epure Elena-Luiza, Constantin Catalin-Paul, Damaceanu Mariana-Dana, Ursu Elena-Laura, Mihaila Ilarion, Sava Ion
"Petru Poni" Institute of Macromolecular Chemistry, 700487 Iasi, Romania.
Faculty of Chemical Engineering and Environmental Protection, "Gheorghe Asachi" Technical University, 700050 Iasi, Romania.
Nanomaterials (Basel). 2021 Mar 22;11(3):812. doi: 10.3390/nano11030812.
Aromatic polyimides containing side azo-naphthalene groups have been investigated regarding their capacity of generating surface relief gratings (SRGs) under pulsed UV laser irradiation through phase masks, using different fluencies and pulse numbers. The process of the material photo-fluidization and the supramolecular re-organization of the surface were investigated using atomic force microscopy (AFM). At first, an AFM nanoscale topographical analysis of the induced SRGs was performed in terms of morphology and tridimensional amplitude, spatial, hybrid, and functional parameters. Afterward, a nanomechanical characterization of SRGs using an advanced method, namely, AFM PinPoint mode, was performed, where the quantitative nanomechanical properties (i.e., modulus, adhesion, deformation) of the nanostructured azo-polyimide surfaces were acquired with a highly correlated topographic registration. This method proved to be very effective in understanding the formation mechanism of the surface modulations during pulsed UV laser irradiation. Additionally to AFM investigations, confocal Raman measurements and molecular simulations were performed to provide information about structured azo-polyimide chemical composition and macromolecular conformation induced by laser irradiation.
含侧基偶氮萘基团的芳香族聚酰亚胺已被研究，考察其在脉冲紫外激光通过相位掩膜照射下产生表面起伏光栅（SRG）的能力，实验采用了不同的能量密度和脉冲数。利用原子力显微镜（AFM）研究了材料的光流体化过程以及表面的超分子重组。首先，从形态学、三维振幅、空间、混合和功能参数方面对诱导产生的SRG进行了AFM纳米级形貌分析。随后，使用一种先进方法，即AFM针尖模式对SRG进行了纳米力学表征，通过高度相关的形貌配准获得了纳米结构偶氮聚酰亚胺表面的定量纳米力学性能（即模量、粘附力、变形）。该方法在理解脉冲紫外激光照射期间表面调制的形成机制方面被证明非常有效。除了AFM研究外，还进行了共聚焦拉曼测量和分子模拟，以提供有关激光照射诱导的结构化偶氮聚酰亚胺化学成分和大分子构象的信息。
