Determination of Young's Modulus for Nanofibrillated Cellulose Multilayer Thin Films Using Buckling Mechanics
Determination of Young's Modulus for Nanofibrillated Cellulose Multilayer Thin Films Using Buckling Mechanics
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DOI：
10.1021/bm101330w
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发表时间：
2011-04-01
影响因子：
6.2
通讯作者：
Wagberg, Lars
中科院分区：
文献类型：
--
作者：
Cranston, Emily D.;Eita, Mohamed;Wagberg, Lars
采用应变诱导弹性屈曲不稳定性力学测量（SLEBIMM）技术测定了纳米原纤化纤维素（NFC）和聚乙烯亚胺（PEI）多层膜的杨氏模量。(1)采用静电逐层组装法在聚二甲基硅氧烷基底上制备多层膜。在50%相对湿度下，SIEBIMM对于35-75 nm厚的膜给出1.5 +/-0.2GPa的恒定杨氏模量。相反，在真空中，杨氏模量大10倍，为17.2 +/- 1.2 GPa。通过扫描电子显微镜原位压缩观察到屈曲波长随应变的增加而略有减小，并且在10%应变以上，发生平行于压缩方向的广泛开裂。我们的结论是，尽管PEI充当“胶水”将多层NFC保持在一起，但它阻止了氢键和特定原纤维-原纤维相互作用的充分发展，并且在高湿度下，与纯NFC膜相比，其吸湿性降低了弹性模量。
The Young's modulus of multilayer films containing nanofibrillated cellulose (NFC) and polyethyleneimine (PEI) was determined Using the strain-induced elastic buckling instability for mechanical measurements (SLEBIMM) technique.(1) Multilayer films were built up on polydimethylsiloxane substrates using electrostatic layer-by-layer assembly. At 50% relative humidity, SIEBIMM gave a constant Young's modulus of 1.5 +/- 0.2 GPa for 35-75 run thick films. Conversely, in vacuum, the Young's modulus was 10 times larger, at 17.2 +/- 1.2 GPa. A slight decrease in buckling wavelength with increasing strain was observed by scanning electron microscopy with in situ compression, and above 10% strain, extensive cracking parallel to the compressive direction occurred. We conclude that whereas PEI acts as a "glue" to hold multiple layers of NFC together, it prevents full development of hydrogen bonding and specific fibril-fibril interactions, and at high humidity, its hygroscopic nature decreases the elastic modulus when compared with pure NFC films.