Anyfantakis M, Pamvouxoglou A, Mantzaridis C, Pispas S, Butt H-J, Fytas G, Loppinet B
FO. R. T. H., Institute of Electronic Structure & Laser , 71110 Heraklion Crete, Greece.
Dept. of Chemistry, University of Crete , 71003 Heraklion, Greece.
J Phys Chem B. 2017 Jul 27;121(29):7180-7189. doi: 10.1021/acs.jpcb.7b02239. Epub 2017 Jul 14.
When exposed to weak visible laser light, solutions of common polymers like poly(isoprene) and poly(butadiene) respond by local concentration variations, which in turn lead to refractive index changes. Various micropatterns have been recently reported, depending mostly on the solvent environment and the irradiation conditions. Here, we focused on the simpler case of single polymer-rich filaments and we employed phase contrast microscopy to systematically investigate the influence of laser illumination and material parameters on the kinetics of the optically induced local concentration increase in the polydiene solutions. The refractive index contrast of the formed filaments increased exponentially with the laser illumination time. The growth rate exhibited linear dependence on the laser power and increased with polymer chain length in semidilute solutions in good solvents. On the contrary, the kinetics of the formed filaments appeared to be rather insensitive to the polymer concentration. Albeit the origin of the peculiar light field-polymer concentration coupling remains yet elusive, the new phenomenology is considered necessary for the elucidation of its mechanism.
当暴露于弱可见光激光下时，诸如聚异戊二烯和聚丁二烯等常见聚合物溶液会通过局部浓度变化做出响应，这反过来又会导致折射率变化。最近报道了各种微图案，这主要取决于溶剂环境和辐照条件。在此，我们聚焦于更简单的单一富含聚合物细丝的情况，并采用相衬显微镜系统地研究激光照射和材料参数对聚二烯溶液中光致局部浓度增加动力学的影响。所形成细丝的折射率对比度随激光照射时间呈指数增加。在良溶剂中的半稀溶液中，生长速率对激光功率呈线性依赖，并随聚合物链长增加。相反，所形成细丝的动力学似乎对聚合物浓度相当不敏感。尽管这种特殊的光场 - 聚合物浓度耦合的起源仍然难以捉摸，但这种新现象学被认为对于阐明其机制是必要的。
