The in-plane coefficient of thermal expansion (CTE) of freestanding multilayer pristine graphene was directly measured by the thermal bulge method using a white light interferometric microscope. Graphene ribbons with 3, 5, and 10 layers were prepared by exfoliation of high-quality graphite flakes and then transferred over 60–120 μm wide trenches in a Si substrate. A novel transfer procedure was developed to achieve the freestanding configuration. All the measured CTE values were negative in the temperature range of 25–150 °C, and their absolute values decreased with increasing temperature and number of layers. The CTE of monolayer graphene can be approximated to about -7 × 10^-6/°C. It was speculated that a structure with more than 12 layers was graphite rather than graphene.

独立式多层原始石墨烯的面内热膨胀系数（CTE）通过热膨胀法使用白光干涉显微镜直接测量。通过剥落高质量的石墨薄片来制备具有3、5和10层的石墨烯带，然后将其转移到Si基板中60-120μm宽的沟槽中。开发了一种新颖的转移程序以实现独立配置。在25–150°C的温度范围内，所有测得的CTE值均为负值，并且其绝对值随温度和层数的增加而降低。单层石墨烯的CTE可以约为-7×10 ^-6 /°C。据推测，具有超过12层的结构是石墨而不是石墨烯。