Over the past few years, smart fibres have seen tremendous growth, especially in terms of research funding and development of start-ups. However, succeeding in reaching the consumer market are a very few products. Indeed, one of the main challenges remains the lack of standardised test methods to evaluate properties and performance of smart fibres. In this review paper, we will talk about the history, applications, future readiness of smart fibres. Smart textiles synonymously known as electronic textiles, e-textiles, intelligent textiles, and alike is a class of materials, where textiles play a vital role but where functionalities from other disciplines are added.

In technical textile area significant progresses have been achieved in last few years. There are many separate and distinct fields of science and engineering. Considerable movement and convergence has takes place between these fields of endeavour and results have been astonishing. One of these results is Smart technology for materials and structures. Smart textiles are one of the exciting new frontier technologies in engineering and manufacturing. Due advantages in many technologies coupled with advances in textile materials and structures smart fibres are possible. Biotechnology, information technology, microelectronics, wearable computers, nanotechnology and micro electromechanical machine are included in partial list.

There are three categories in which smart fibres are classified according to their function. Results in an outcome named as smart textiles are the amalgamation of electronic components and advanced fibres with manmade textiles extend the field of  material science and digital electronics. Often even before we do the world of fashion knows what we want to wear. Be it the trending hemlines or the latest accessories, designers around the world predict and often create the future when it comes to preference. Smart fibres is one thing that has been picked up by a lot of such visionary designers.

Smart fibres are created by modified textile material and miniaturised electronic devices [3].

Definition
Smart fibres and structures can be defined as materials and structures that can sense and react to environmental conditions or stimuli , such as those from mechanical, thermal, chemical, electrical, magnetic or other sources. Smart fabrics have been defined as fabrics which are defined and manufactured to include technologies that provide to the user increased functionality.

Classification
Fibres can be divided into three materials according to manner of reaction, smart passive smart, active smart and very smart materials. Sensors, actuators and controlling units are three components present in materials on which smart fibres are classified. These classifications are as follows:

a)Passive smart materials

Materials which can only sense to environmental conditions or stimuli are called passive smart materials. These fibres are called as first generation of smart fibres. Passive smart fabric textiles still fall short of the scope of smart fabric textile in strict sense, and should be more accurately called functional fabric textiles.

b) Active smart materials

The materials that can sense and react to condition or stimuli are called as active smart fibres. These are also called as second generation of smart fibres. Shape memory fabric textiles are examples of active smart fibres.

c) Very smart materials
The materials can sense, react and adopt themselves accordingly are called as very smart materials. They are also called as advanced smart materials or adaptive smart fabric textiles.

History
STEVE MANN is known as “the father of wearable computing”.  He often refers to the abacus ring as one of the first pieces of wearable technology. There were much effort and researches on smart textiles since the mid of 1980. EU, European space agency, NASA, giant companies and industries like Adidas and industry members are some different groups who put funds to R and D for different end uses. Such researches are carried out by EU, European Space Agency, government agencies, NASA, giant companies and industries like Adidas. The aim is to initiate restructuring, strengthening and commercial
developments of products of smart textiles.

Around 1000 years ago, conductive threads and fabrics have been developed which are needed to construct E-textiles. At the end of 19th century, people develop and grew accustomed to electric appliances, designers and engineering. They begin to combine electricity with clothing and jewel-designing. At the museum of contemporary craft in New York City, ground breaking exhibition called body covering was held which is focused on relationship between technology and apparel.
The first fully animated sweatshirt was invented by Harry Wainwright, in 1985; which consist of fibre optics leads and microprocessor.

Application
Body conformal antennas for integrated radio equipment into clothing, power and data transmission– a personal area network, flexible photovoltaic integrated into textile fabrics, physiological status monitoring to hydration and nutritional status as well as more conventional heart monitoring; smart footwear to let you know where you are and to convert and conserve energy and of course, phase change material for heating and cooling of individual. Another application is weaving
of sensors into parachutes to avoid obstacles and steer parachutes or cargo load to precise location.

Shape memory polymers have been applied to textiles in fibres, films and foam forms, resulting in range of high-performance fabrics and garments, especially seagoing garments. Fibre sensors, which are capable of measuring temperatures strain/stress, gas, biological species and smell, are typically smart fibres that can be directly applied to textiles. Conductive polymer-based actuators have achieved very high level of energy density.

Applications of smart fibres are as follows:
1. Medical and healthcare monitoring and diagnostics
2. Sportswear and fitness monitoring (bands)
3. Consumer electronics such as smart watches, smart glasses and headsets.
4. Military global positioning system (GPS) trackers, equipment (helmets) and wearable robots.

5. Smart apparel and footwear in fashion and sport.
6. Workplace safety and manufacturing.

Either directly from military R&D or from spin offs the initial application of smart fibres have come. Sensing and responding are the capabilities of smart fibres which are responsible for this application.

Future
At present, smart textiles are one of focus topics in multi-disciplinary research and target a great variety of applications, smart textiles is a clear priority for the future of textiles and clothing in developed countries. In recent years, with development of intelligent system, smart fibres have been widely researched. Whether for performance or aesthetic reason, the focus within textile area is on smart fabrics from those that change their hue to those that regulate body temperature. Smart cothes in future could have self-healing property. Smart fibres in future will monitor our health and help us to keep healthy and fit. The bras can already contain heart rate sensor.

Smart textiles market has experienced tremendous growth over the past few years in sections, such as medical, healthcare, automotive and sport industries, where these textiles offer significant potential for medical and healthcare applications and make diagnosis far more accurate and quicker. Readiness of smart fibres for market Exponential growth of interest smart and interactive fibres has grown in last few years. With the gradual reduction of component costs, the commercialization