Nanomechanical Thermal Analysis with Silicon Cantilevers of the Mechanical Properties of Poly(vinyl acetate) near the Glass Transition Temperature
Nanomechanical Thermal Analysis with Silicon Cantilevers of the Mechanical Properties of Poly(vinyl acetate) near the Glass Transition Temperature
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DOI：
10.1021/ma8020695
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发表时间：
2008-12-23
期刊：
影响因子：
5.5
通讯作者：
Jeon, Sangmin
中科院分区：
文献类型：
--
作者：
Jung, Namchul;Jeon, Sangmin
将聚醋酸乙烯酯(PVAc)涂覆在硅悬臂梁的一侧，同时测量了涂覆PVAc的硅悬臂梁的挠度、共振频率和Q值随温度的变化。悬臂梁的谐振频率的变化和Q因子的倒数分别与PVAc的弹性模数和损耗正切的变化有关。根据共振频率和Q因子计算出PVAc的损耗模数，并用来确定PVAc的玻璃化转变温度(T-g)(66℃)，发现T-g高于由悬臂梁挠度(43℃)获得的玻璃化转变温度；这种差异归因于悬臂梁的高共振频率(或施加应力的快速速率)。在不同频率下进行了一系列测量，以获得准确的玻璃化转变的T-g和表观活化能。
Poly(vinyl acetate) (PVAc) was coated onto one side of a silicon cantilever, and the variations with temperature in the deflection, resonance frequency, and Q factor of the PVAc-coated silicon cantilever were measured simultaneously. The changes in the resonance frequency and the inverse of the Q factor of the cantilever are related to the variations in the elastic modulus and the loss tangent of PVAc, respectively. The loss modulus of PVAc was calculated from the resonance frequency and Q factor and used to determine the glass transition temperature (T-g) of PVAc (66 degrees C), which was found to be higher than that obtained from the cantilever deflection (43 degrees C); this difference is attributed to the high resonance frequency of the cantilever (or the fast rate of the applied stress). A series of measurements at various frequencies were carried out to obtain the accurate T-g and apparent activation energy for the glass transition.