Cancer is a leading cause of death in the world. In cancer radiotherapy, immobilization membranes composed of cross‐linked poly(ε‐caprolactone) (PCL) are utilized for patient positioning. A higher‐dimensional stability of the membrane is urgently required to facilitate more accurate radiation dose delivery. It is extremely important to establish the relationship between the degree of crystallinity and the Young's modulus (
E
) because it determines the mechanical properties and can be modulated by crystallinity. When two components of the membrane with different strains are in contact, a gradient region adjacent to the interface is formed and confirmed by attenuated total reflection infrared microscopy. Atomic force microscopy (AFM) and Raman spectroscopy are used to scan the same area in the gradient region (14 µm × 14 µm) to characterize
E
and crystallinity (
X
Raman
), respectively. This co‐localized method ensures the accuracy of the relationship. Finally, 1764 AFM measurement data are processed and 49 pairs of
E
‐
X
Raman
data are obtained. The regression curve shows that
E
monotonically increases with
X
Raman
. The nonlinearity of the curve may be attributed to the α‐relaxation and cross‐linking of PCL chains. The chemical structure of this material significantly impacts the mechanical properties, thus requiring future investigation.
Raman spectra are often masked by strong fluorescence,
which severely
hinders the applications of Raman spectroscopy. Herein, for the first
time, we report ionic-wind-enhanced Raman spectroscopy (IWERS) incorporated
with photobleaching (PB) as a noninvasive approach to detect fluorescent
and vulnerable samples without a substrate. In this study, ionic wind
(IW) generated by needle-net electrodes transfers charges to the sample
surface in air on the scale of millimeters rather than nanometers
in surface-enhanced Raman spectroscopy. Density functional theory
calculations reveal that the ionic particles in IW increase the susceptibility
of the sample molecules, thus enhancing the Raman signals. Meanwhile,
the incorporation of IW with PB yields a synergistic effect to quench
fluorescence. Therefore, this approach can improve the signal-to-noise
ratio of Raman peaks up to three times higher than that with only
PB. At the same time, IWERS can avoid sample pollution and destruction
without substrates as well as high laser power. For archeological
samples and a red rock as an analogue to Mars geological samples,
IWERS successfully identified weak but key Raman peaks, which were
masked by strong florescence. It suggests that IWERS is a promising
tool for characterizations in the fields of archeology, planetary
science, biomedicine, and soft matter.
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