Grabowski Christopher A, Mukhopadhyay Ashis
Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48201, USA.
Phys Rev Lett. 2007 May 18;98(20):207801. doi: 10.1103/PhysRevLett.98.207801. Epub 2007 May 15.
We have studied the conformation change of a flexible linear polymer chain near the critical point of a binary liquid mixture using fluorescence correlation spectroscopy, which measured the hydrodynamic radius of the chains. Our results indicate that as the critical temperature (Tc) is approached, the chain size decreases. The polymer attains its most compact conformation when the correlation length of the critical fluctuations becomes comparable to the coil size. At very close to Tc, the polymer reexpands dramatically. To our knowledge, this is the first experimental evidence supporting the prediction of Brochard and de Gennes that a polymer chain will collapse and subsequently reswell on approaching Tc.
我们使用荧光相关光谱研究了柔性线性聚合物链在二元液体混合物临界点附近的构象变化，该光谱测量了链的流体力学半径。我们的结果表明，随着接近临界温度（Tc），链尺寸减小。当临界涨落的关联长度与线团尺寸可比时，聚合物达到其最紧密的构象。在非常接近Tc时，聚合物会急剧重新膨胀。据我们所知，这是支持布罗沙尔和德热纳预测的首个实验证据，即聚合物链在接近Tc时会塌缩并随后再膨胀。
