Fernández-López Cristina, Polavarapu Lakshminarayana, Solís Diego M, Taboada José M, Obelleiro Fernando, Contreras-Cáceres Rafael, Pastoriza-Santos Isabel, Pérez-Juste Jorge
†Departamento de Química Física, CINBIO, Universidade de Vigo and Instituto de Investigación Biomédica de Vigo (IBIV), 36310 Vigo, Spain.
‡Departamento de Teoría de la Señal y Comunicaciones, Universidade de Vigo, 36310 Vigo, Spain.
ACS Appl Mater Interfaces. 2015 Jun 17;7(23):12530-8. doi: 10.1021/am5087209. Epub 2015 Apr 7.
The thermoresponsive optical properties of Au nanorod-doped poly(N-isopropylacrylamide) (Au NR-pNIPAM) microgels with different Au NR payloads and aspect ratios are presented. Since the volume phase transition of pure pNIPAM microgels is reversible, the optical response reversibility of Au NR-pNIPAM hybrids is systematically analyzed. Besides, extinction cross-section and near-field enhancement simulations for Au NR-microgel hybrids are performed using a new numerical method based on the surface integral equation method of moments formulation (M3 solver). Additionally, the Au NR-microgel hybrid systems are expected to serve as excellent broadband surface-enhanced Raman scattering (SERS) substrates due to the temperature-controlled formation of hot spots and the tunable optical properties. The optical enhancing properties related to SERS are tested with three laser lines, evidencing excitation wavelength-dependent efficiency that can be easily controlled by either the aspect ratio (length/width) of the assembled Au NR or by the Au NR payload per microgel. Finally, the SERS efficiency of the prepared Au NR-pNIPAM hybrids is found to be stable for months.
本文展示了具有不同金纳米棒负载量和纵横比的金纳米棒掺杂聚（N-异丙基丙烯酰胺）（Au NR-pNIPAM）微凝胶的热响应光学性质。由于纯pNIPAM微凝胶的体积相变是可逆的，因此对Au NR-pNIPAM杂化物的光学响应可逆性进行了系统分析。此外，使用基于矩量法表面积分方程公式的新数值方法（M3求解器）对Au NR-微凝胶杂化物进行了消光截面和近场增强模拟。此外，由于热点的温度控制形成和可调光学性质，Au NR-微凝胶杂化系统有望用作优异的宽带表面增强拉曼散射（SERS）基底。用三条激光线测试了与SERS相关的光学增强性质，证明了激发波长依赖性效率，该效率可通过组装的Au NR的纵横比（长度/宽度）或每个微凝胶的Au NR负载量轻松控制。最后，发现制备的Au NR-pNIPAM杂化物的SERS效率在数月内保持稳定。
