1. PRESENTED BY
DEBASISH MAHATA
ROLL NO: JFT-15
email id:- debu.ijt@gmail.com
D.J.F.T, UNIVERSITY OF CALCUTTA
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2. INTRODUCTION
Consumer demand of unique appearance, increased
performance and multifunctionality of the woven items,
smart textiles became an active area of current research.
Various applications of smart textiles include interactive
clothing for sports, hazardous occupations, and military,
industrial textiles with integrated sensors or signage,
fashion accessories and apparel with unique and variable
appearance. Major advances in the textile capabilities can
only be achieved through further development of its
fundamental element - a fiber. In this work we discuss the
prospectives of Photonic Band Gap (PBG) fibers in
photonic textiles.
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3. Total Internal Reflection (TIR) fibers modified to emit
light sideways have been used to produce emissive
fashion items, as well as backlighting panels for medical
and industrial applications. To implement such emissive
textiles one typically uses common silica or plastic optical
fibers in which light extraction is achieved through
corrugation of the fiber surface, or through fiber micro
bending. photonic textiles, a vast body of research has
been conducted to understand and to be able to design the
light scattering properties of synthetic non-optical fibers.
We start, by comparing the operational principles of the
TIR fibers and PBG fibers for applications in optical
textiles. We then highlight technical advantages offered by
the PBG fibers, compared to the TIR fibers, for the light
extraction from the optical fibers.
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4. Extraction of light from the optical fibers:‐
Light extraction from optical fibers. a) Microbending in TIR fibers. b)
Surface corrugation in TIR fibers. c) Leaky modes in straight hollow core
PBG fibers. d) Leaky modes in straight low refractive index solid core PBG
fibers with scatterers at the fiber/air interface.
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5. UNDERSTANDING THE COLORS OF PBG FIBERS:‐
Colorful PBG Bragg fibers. a)When launching white light into the Bragg
fibers, after a few cm from the coupling end the fibers appear intensely
colored. Color of an individual fiber is defined by the spectral position of the
fiber reflector band gap. b) Under ambient illumination, semi‐transparent
Bragg fibers appear colored again. Fiber color in reflection of the ambient
light can be different from the color due to emission of guided light.
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6. Color‐changing textiles under the variable
ambient illumination:‐
a) Schematic of a color changing fiber. Color of a PBG fiber can be varied by mixing the
emitted guided color with the reflected color from ambient illumination.
b) Experimental demonstration of color mixing. c) A collection of lit fibers under strong
ambient illumination. Both the emitted guided colors (especially visible at the fiber
peripheries) and the reflected colors (especially visible along the fiber center lines) are
visible. 6

7. Color‐on‐demand textiles using RGB yarns:‐
a) RGB yarn in the form of a braid of three fibers of R, G and B colors. b)
Schematic of a color‐on‐demand textile setup.
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8. Experimental realization of the PBG fiber‐
based textiles:‐
PBG Bragg fiber-based textile with a white silk matrix. When externally
illuminated the textile appears highly reflective showing stripes of different
colors. When looked closely, the colored stripes are made of fibers of similar
diameters; supporting silk ground cloth is visible through the transparent colored
fibers.
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9. Optical response of plastic PBG fibers to
mechanical stretching:‐
PBG fiber textile and light coupling setup. a) Lit textile under the normal
ambient illumination in the laboratory. b) Lit textile in the dark.
The change in the fiber transmitted and reflected colors. One would expect
thatunder mechanical strain, fiber dimensions would vary, thus having an impact
on both the fiber appearance and transmission spectrum
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10. COLOUR CHANGING APPLICATIONS IN
TEXTILE CHEMISTRY
Fiber's and coatings with unique optical, magnetic and electrical
properties are being widely researched for both military and
commercial applications. New materials are being developed in
this research effort, with unique tunable coloration properties
across the visible spectrum as well as spanning the infrared and
ultraviolet region of the electromagnetic spectrum. These
dynamic color-responsive ‘camouflage’ fibre systems will have
wide application to a variety of new textile products.
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11. Methods for production of camouflage
textiles
A. pH changes
B. Oxidation state changes
C. Bond breaking/making
D. Mechanochromism
E. Electric or magnetic field effects
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12. Chromic materials:
• Photochromic: external stimuli energy is light.
• Thermochromic: external stimuli energy is heat.
• Electrochromic: external stimuli energy is electricity.
• Piezorochromic: external stimuli energy is pressure.
• Solvatochromic: external stimuli energy is liquid.
• Carsolchromic: external stimuli energy is electron
beam.
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13. CONCLUSION:‐
We have presented an implementation of a photonic textile
based on plastic Photonic Band gap Bragg fibers for potential
applications in smart cloths, signage and art. It was established
that under ambient illumination Bragg fibers appear colored
due to optical interference in their microstructure. Compared to
other existing PBG fibers, all-plastic Bragg fibers currently
offer the most economical solution required by the textile
applications.
 The creation of fi eld-responsive fi bras, camouflage fi bras, is
a multi-disciplinary endeavour. In addition to chromophores,
polymeric materials may be able to generate a uniform, stable
fi eld for excitation of the color change processes.
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14. THANK YOU
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