Jayamaha Hansadi, Ugras Thomas J, Page Kirt A, Hanrath Tobias, Robinson Richard D, Shepherd Larissa M
Department of Human Centered Design, Cornell University, Ithaca, New York 14853, United States.
School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States.
ACS Appl Mater Interfaces. 2024 Apr 10;16(14):17757-17765. doi: 10.1021/acsami.3c17623. Epub 2024 Mar 27.
Controllable synthesis of homochiral nano/micromaterials has been a constant challenge for fabricating various stimuli-responsive chiral sensors. To provide an avenue to this goal, we report electrospinning as a simple and economical strategy to form continuous homochiral microfibers with strain-sensitive chiroptical properties. First, electrospun homochiral microfibers from self-assembled cadmium sulfide (CdS) quantum dot magic-sized clusters (MSCs) are produced. Highly sensitive and reversible strain sensors are then fabricated by embedding these chiroptically active fibers into elastomeric films. The chiroptical response on stretching is indicated quantitatively as reversible changes in magnitude, spectral position (wavelength), and sign in circular dichroism (CD) and linear dichroism (LD) signals and qualitatively as a prominent change in the birefringence features under cross-polarizers. The observed periodic twisted helical fibrils at the surface of fibers provide insights into the origin of the fibers' chirality. The measurable shifts in CD and LD are caused by elastic deformations of these helical fibrillar structures of the fiber. To elucidate the origin of these chiroptical properties, we used field emission-electron microscopy (FE-SEM), atomic force microscopy (AFM), synchrotron X-ray analysis, polarized optical microscopy, as well as measurements to isolate the true CD, and contributions from photoelastic modulators (PEM) and LD. Our findings thus offer a promising strategy to fabricate chiroptical strain-sensing devices with multiple measurables/observables using electric-field-assisted spinning of homochiral nano/microfibers.
可控合成手性纳米/微米材料一直是制造各种刺激响应型手性传感器的持续挑战。为实现这一目标，我们报道了静电纺丝作为一种简单且经济的策略，用于形成具有应变敏感手性光学性质的连续手性微纤维。首先，通过自组装硫化镉（CdS）量子点魔法尺寸团簇（MSCs）制备静电纺手性微纤维。然后，将这些具有手性光学活性的纤维嵌入弹性体薄膜中，制造出高灵敏度和可逆的应变传感器。拉伸时的手性光学响应在定量上表现为圆二色性（CD）和线性二色性（LD）信号的大小、光谱位置（波长）和符号的可逆变化，在定性上表现为在交叉偏振器下双折射特征的显著变化。在纤维表面观察到的周期性扭曲螺旋纤维为纤维手性的起源提供了见解。CD和LD中可测量的变化是由纤维的这些螺旋纤维结构的弹性变形引起的。为了阐明这些手性光学性质的起源，我们使用了场发射电子显微镜（FE-SEM）、原子力显微镜（AFM）、同步加速器X射线分析、偏振光学显微镜，以及测量以分离真正的CD，以及来自光弹性调制器（PEM）和LD的贡献。因此，我们的研究结果提供了一种有前景的策略，通过电场辅助纺丝制备具有多种可测量/可观察量的手性光学应变传感装置。
