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Photonic sensing of organic solvents through geometric study of dynamic reflection spectrum.

Zhang Y, Fu Q, Ge J - Nat Commun (2015)

Bottom Line: Traditional photonic sensing based on the change of balanced reflection of photonic structures can hardly distinguish chemical species with similar refractive indices.There are inherent relationships between solvent properties, diffusion behaviour and evolution of reflection signals, so that the geometric characteristics of DRS pattern including ascending/descending, colour changes, splitting/merging and curvature of reflection band can be utilized to recognize different organic solvents.With adequate solvents being tested, a database of DRS patterns can be established, which provide a standard to identify an unknown solvent.

View Article: PubMed Central - PubMed

Affiliation: 1] Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China [2] Department of Chemistry, Tongji University, Shanghai 200092, China.

ABSTRACT
Traditional photonic sensing based on the change of balanced reflection of photonic structures can hardly distinguish chemical species with similar refractive indices. Here a sensing method based on the dynamic reflection spectra (DRS) of photonic crystal gel has been developed to distinguish even homologues, isomers and solvents with similar structures and physical properties. There are inherent relationships between solvent properties, diffusion behaviour and evolution of reflection signals, so that the geometric characteristics of DRS pattern including ascending/descending, colour changes, splitting/merging and curvature of reflection band can be utilized to recognize different organic solvents. With adequate solvents being tested, a database of DRS patterns can be established, which provide a standard to identify an unknown solvent.

No MeSH data available.


Determination of the direction of solvent diffusion.Microscopic images of colloidal crystals in the surface layer (P1) and inner layer (P2) of (a) a green and (b) a red photonic gel, when they are covered by (a) i-butanol and (b) acetyl acetate, respectively. Scale bars, 50 μm.
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f3: Determination of the direction of solvent diffusion.Microscopic images of colloidal crystals in the surface layer (P1) and inner layer (P2) of (a) a green and (b) a red photonic gel, when they are covered by (a) i-butanol and (b) acetyl acetate, respectively. Scale bars, 50 μm.

Mentions: The judgements of solvent diffusion and extraction are supported by the spatial change of structural colours inside the gel. Since the gel is composed of transparent amorphous domains and colourful crystalline domains, one can directly observe the colloidal microcrystals in the surface layer (P1) or the inner layer (P2) by tuning the focus plane on a reflection-mode optical microscope. Generally, the crystals on focus have sharp edges while those under or over focus are quite blurry, which makes it possible to attribute each crystal to P1 or P2 plane. When a green gel is covered by butanol, the microcrystals in the surface layer turn red and those in the inner layer remain green, which demonstrates the diffusion of butanol into the gel from the surface layer (Fig. 3, Supplementary Fig. 4). For the case of acetyl acetate tested on a red gel, the surface crystals turn green while the inner crystals remain red, indicating the extraction of EG from the gel.


Photonic sensing of organic solvents through geometric study of dynamic reflection spectrum.

Zhang Y, Fu Q, Ge J - Nat Commun (2015)

Determination of the direction of solvent diffusion.Microscopic images of colloidal crystals in the surface layer (P1) and inner layer (P2) of (a) a green and (b) a red photonic gel, when they are covered by (a) i-butanol and (b) acetyl acetate, respectively. Scale bars, 50 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4557364&req=5

f3: Determination of the direction of solvent diffusion.Microscopic images of colloidal crystals in the surface layer (P1) and inner layer (P2) of (a) a green and (b) a red photonic gel, when they are covered by (a) i-butanol and (b) acetyl acetate, respectively. Scale bars, 50 μm.
Mentions: The judgements of solvent diffusion and extraction are supported by the spatial change of structural colours inside the gel. Since the gel is composed of transparent amorphous domains and colourful crystalline domains, one can directly observe the colloidal microcrystals in the surface layer (P1) or the inner layer (P2) by tuning the focus plane on a reflection-mode optical microscope. Generally, the crystals on focus have sharp edges while those under or over focus are quite blurry, which makes it possible to attribute each crystal to P1 or P2 plane. When a green gel is covered by butanol, the microcrystals in the surface layer turn red and those in the inner layer remain green, which demonstrates the diffusion of butanol into the gel from the surface layer (Fig. 3, Supplementary Fig. 4). For the case of acetyl acetate tested on a red gel, the surface crystals turn green while the inner crystals remain red, indicating the extraction of EG from the gel.

Bottom Line: Traditional photonic sensing based on the change of balanced reflection of photonic structures can hardly distinguish chemical species with similar refractive indices.There are inherent relationships between solvent properties, diffusion behaviour and evolution of reflection signals, so that the geometric characteristics of DRS pattern including ascending/descending, colour changes, splitting/merging and curvature of reflection band can be utilized to recognize different organic solvents.With adequate solvents being tested, a database of DRS patterns can be established, which provide a standard to identify an unknown solvent.

View Article: PubMed Central - PubMed

Affiliation: 1] Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China [2] Department of Chemistry, Tongji University, Shanghai 200092, China.

ABSTRACT
Traditional photonic sensing based on the change of balanced reflection of photonic structures can hardly distinguish chemical species with similar refractive indices. Here a sensing method based on the dynamic reflection spectra (DRS) of photonic crystal gel has been developed to distinguish even homologues, isomers and solvents with similar structures and physical properties. There are inherent relationships between solvent properties, diffusion behaviour and evolution of reflection signals, so that the geometric characteristics of DRS pattern including ascending/descending, colour changes, splitting/merging and curvature of reflection band can be utilized to recognize different organic solvents. With adequate solvents being tested, a database of DRS patterns can be established, which provide a standard to identify an unknown solvent.

No MeSH data available.