Ovchinnikov I S, Vishnevskiy A S, Seregin D S, Rezvanov A A, Schneider D, Sigov A S, Vorotilov K A, Baklanov M R
MIREA-Russian Technological University (RTU MIREA), Vernadsky Avenue 78, Moscow 119454, Russian Federation.
Moscow Institute of Physics and Technology (MIPT), 9 Institutskiy per., Dolgoprudny, Moscow Region 141700, Russian Federation.
Langmuir. 2020 Aug 18;36(32):9377-9387. doi: 10.1021/acs.langmuir.0c01054. Epub 2020 Aug 7.
Characterization of mechanical properties of thin porous films with nanoscale resolution remains a challenge for instrumentation science. In this work, atomic force microscopy (AFM) in the PeakForce quantitative nanomechanical mapping (PFQNM) mode is used for Young's modulus measurements of porous organosilicate glass films. The test samples were prepared by sol-gel techniques using silicon alkoxide and methyl-modified silicon alkoxide to prepare films with different CH/Si ratios. The film porosity was engineered by using a Brij 30 template and the evaporation-induced self-assembly technique. The chemical composition, pore structure, and modification during air storage and thermal annealing were studied using FTIR spectroscopy and ellipsometric porosimetry (EP). Since PFQNM AFM was first used for evaluation of Young's modulus of thin porous films, the obtained results are benchmarked using nanoindentation (NI), surface acoustic wave (SAW) spectroscopy, and EP. The results have good agreement with each other, but PFQNM and NI give slightly larger values than SAW and EP. The difference is in agreement with previously reported data and reflects the different physical meaning of the obtained values. It is shown that the presence of physically adsorbed water strongly influences the results generated by PFQNM AFM, and therefore, reliable water removal from the studied materials is necessary.
对具有纳米级分辨率的薄多孔膜的力学性能进行表征，仍然是仪器科学面临的一项挑战。在这项工作中，采用峰值力定量纳米力学映射（PFQNM）模式下的原子力显微镜（AFM）来测量多孔有机硅酸盐玻璃薄膜的杨氏模量。测试样品通过溶胶 - 凝胶技术制备，使用硅醇盐和甲基改性硅醇盐来制备具有不同CH/Si比的薄膜。通过使用Brij 30模板和蒸发诱导自组装技术来设计薄膜的孔隙率。使用傅里叶变换红外光谱（FTIR）和椭圆偏振光孔隙率测定法（EP）研究了在空气储存和热退火过程中的化学成分、孔结构和改性情况。由于PFQNM AFM首次用于评估薄多孔膜的杨氏模量，因此使用纳米压痕（NI）、表面声波（SAW）光谱和EP对所得结果进行了基准测试。结果彼此之间具有良好的一致性，但PFQNM和NI给出的值比SAW和EP略大。这种差异与先前报道的数据一致，反映了所得值的不同物理意义。结果表明，物理吸附水的存在强烈影响PFQNM AFM产生的结果，因此，必须从研究材料中可靠地去除水分。
