Examples of smart textiles

Question 1

Name 3 applications for photochromism on textiles

Answer 1

UV exposure
Security printing/ brand protection
Design effects

Question 2

Explain how chromic materials work.

Answer 2

• stimulus is applied to dye colour 1, changing it to dye colour 2
• stimulus is removed, reverting it back to dye colour 1

Question 3

Name 3 applications for thermochromism in textiles

Answer 3

• Temperature warning signals
• Textile thermometers
• Design effects

Question 4

How do the shape memory materials (SMM) work?

Answer 4

They are materials that will change shape in response to stimulus (usually heat), but revert back to their previous memorised shape when stimulus is removed.

Question 5

Name what applications Shape memory material can be used for

Answer 5

Smart garments
Smart curtain
Medical: Tweezers, Teeth braces, Artificial muscles Fasteners, clips
Switches

Question 6

What are the three ways of generating electricity in textiles that have been explored?

Answer 6

• light harvesting materials (photovoltaics-solar cells)
• use of body heat (thermocouples)
• mechanical motion (piezoelectric materials)

Question 7

Name the practicality issues of incorporating photovoltaics into garments

Answer 7

• Area of photovoltaics required, positioning on the garment
• Pliability
• Method of mounting and connectivity to devices – conducting fibre, soft switch
• Durability in use (laundrability, stress)
• Problems due to variability of sunlight (day-to-day and with latitude), efficiency of
conversion of solar energy into electrical energy.

Question 8

Would thermocouples be effective in textiles?

Answer 8

Indication of power generation possible, but general ineffectiveness of present
thermocouple devices to convert body heat to electrical energy.

Question 9

Would piezoelectric materials be effective in textiles?

Answer 9

Explanation of principle of operation. Indication of power generation possible, and of very
limited range of piezoelectric materials available. Only very low power generation possible.

Question 10

Are photovoltaics effective in textiles?

Answer 10

Indication of power generation possible and of power requirements of devices such as MP3
player, mobile telephone, etc.

Question 11

Name the methods by which textile fibres can be made for conduct electricity

Answer 11

• metallic wires
• coated textile fibres
• inherently conducting textiles

Question 12

What are the advantages and disadvantages of using metallic wires to conduct electricity in textiles?

Answer 12

excellent conductivity, but generally heavier than textile based fibres, not as
flexible, and they are abrasive.

Question 13

What are the advantages and disadvantages of using coated textile fibres to conduct electricity in textiles?

Answer 13

e.g. nylon or polyester coated with either a thin metallic layer or a layer of
conducting textile materials. High conductivities possible, but the coating may crack or peel away during use or laundering, reducing conductivity.

Question 14

What are the advantages/disadvantages of using inherently conducting textiles for conducting electricity in garments?

Answer 14

e.g. polypyrrole, polyaniline types. Reasonably good “textile” properties.
Conductivity is lower than copper or silver, but still good enough. Black colour.

Question 15

How do thermoelectric generators work?

Answer 15

• they turn a temperature difference into an electrical flow

- still experimental

Question 16

How do piezoelectric materials work?

Answer 16

When pressure is applied, a voltage is induced across the material

Question 17

What are the 2 main groups of piezoelectric materials?

Answer 17

• ceramics

- crystals (e.g quartz)