Teichroeb J H, Forrest J A
Department of Physics and Guelph-Waterloo Physics Institute, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
Phys Rev Lett. 2003 Jul 4;91(1):016104. doi: 10.1103/PhysRevLett.91.016104. Epub 2003 Jul 3.
Atomic force microscopy was used to study the embedding of gold nanoparticles into the surface of polystyrene films. The rate of embedding was determined at temperatures near the bulk glass transition temperature T(g) by measuring the apparent nanosphere height as a function of annealing time. In particular, relative height measurements of the adhered particles were made at temperatures below the bulk T(g) value. In the absence of enhanced surface dynamics or yield processes no embedding is expected to occur for T<T(g). Measurements on 10 and 20 nm particles both indicated that the particles did embed 3-4 nm into the polymer for T<T(g). Both the extent and time frame for engulfment appear to be independent of the particle diameter. The results suggest a more mobile surface region on the order of 3-4 nm thick, with a lower glass transition temperature than the bulk.
利用原子力显微镜研究了金纳米颗粒嵌入聚苯乙烯薄膜表面的情况。通过测量表观纳米球高度随退火时间的变化，在接近本体玻璃化转变温度T(g)的温度下确定了嵌入速率。特别地，在低于本体T(g)值的温度下对附着颗粒进行了相对高度测量。在没有增强的表面动力学或屈服过程的情况下，预计对于T<T(g)不会发生嵌入。对10纳米和20纳米颗粒的测量均表明，对于T<T(g)，颗粒确实嵌入聚合物中3-4纳米。吞噬的程度和时间框架似乎都与颗粒直径无关。结果表明存在一个厚度约为3-4纳米的更具流动性的表面区域，其玻璃化转变温度低于本体。
