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首页> 外文会议>North American Thermal Analysis Society conference >Testing the behavior of glass-forming materials: Thermo-viscoelastic measurements on nano- to micro-gram quantities of materials
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Testing the behavior of glass-forming materials: Thermo-viscoelastic measurements on nano- to micro-gram quantities of materials

机译：测试玻璃成型材料的性能：对纳克至微克材料的热粘弹性测量

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Development of methods to measure the viscoelastic response of very small quantities of material has been driven by either the need to determine the nano-mechanical response of, e.g., glass-forming polymers or because unique materials have been produced that are only available in extremely small quantities, viz., vapor deposited materials that form ultra-stable glasses. In the present work we describe the bubble inflation method developed at Texas Tech University for the original purpose of exploring the dynamic (viscoelastic) behavior of ultrathin polymer films by a non-contact nano-mechanical method [1,2]. We describe first results from measurements on ultrathin polymer films in both glassy and above the glass temperature states. In the first instance, reductions in the glass transition temperature of polymer films of as much as 122 oC have been observed [3], while in the latter extreme stiffening that follows a material dependent power law in thickness is reported [4] and found to be consistent with ideas related to the separation of Rouse and segmental modes of relaxation [5]. In addition, we have followed the works of Ediger and co-workers [6,7] in which ultra-stable glasses have been created by a physical vapor deposition process, but now we [8] have succeeded in producing ultra-stable films of amorphous Teflon which show Active temperatures far below the nominal glass transition temperature which allows one to probe the viscoelastic response near to the Kauzmann [9] temperature and in a near to equilibrium state. The TTU bubble inflation experiment permits testing of the small quantities of material produced in the vapor deposition process, viz. nano- to micro-grams in quantity. The results of the experiments are consistent with prior work [9] on an ancient amber material (20 million years old) that is also "ultra-stable" that supports the contention that an "ideal" glass transition does not exist, rather the dynamics deviate from the super-Arrhenius like behavior of the Vogel [11] equation towards an Arrhenius temperature dependence, albeit with a high activation energy.
机译：由于需要确定例如形成玻璃的聚合物的纳米机械响应，或者由于已经生产出仅以极小量提供的独特材料，因此推动了用于测量非常少量材料的粘弹性响应的方法的开发。数量，即形成超稳定玻璃的气相沉积材料。在当前的工作中，我们描述了德克萨斯理工大学开发的气泡膨胀方法，其最初目的是通过非接触纳米机械方法探索超薄聚合物薄膜的动态（粘弹性）行为[1,2]。我们描述了在玻璃态和玻璃态以上的超薄聚合物薄膜上的测量结果。在第一种情况下，已观察到聚合物薄膜的玻璃化转变温度降低了多达122 oC [3]，而在后一种情况下，据报道，这种极端的硬化遵循了材料的幂律定律[4]，并且发现与有关唤醒和分段放松模式的想法相一致[5]。此外，我们遵循了Ediger和同事的工作[6,7]，其中通过物理气相沉积工艺创建了超稳定玻璃，但是现在[8]我们已经成功地生产了超稳定玻璃。非晶特氟隆，其活动温度远远低于标称玻璃化转变温度，这使人们可以探测接近Kauzmann [9]温度并处于接近平衡状态的粘弹性响应。 TTU气泡膨胀实验允许测试气相沉积过程中产生的少量材料，即。纳克至微克的数量。实验结果与先前的研究[9]相一致，后者是古老的琥珀色材料（2000万年），它也是“超稳定的”，支持不存在“理想的”玻璃化转变，而是动力学的观点。尽管具有很高的活化能，但它偏离了Vogel [11]方程的超级像阿伦尼乌斯的行为，对阿伦尼乌斯温度具有依赖性。

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