Block copolymers, an emerging topic in the field of polymer chemistry, demonstrate useful and distinct properties as compared to random copolymers and homopolymers. Today acrylic copolymers are being extensively used in textile for multiple innovative applications like for making specialty fibers etc.
The method of polymerization serves an important role in determining the characteristics of a copolymer. In a simple approach, dispersion polymerization is used to synthesize a variety of copolymers in which an initiator is used to generate monomer radicals. These radicals combine with monomer molecules to form polymeric chains.
Controlled radical polymerization is the modification of above simple method, where the addition of comonomers is regulated depending upon their reactivity ratios to achieve desirable copolymer architecture. Using this technique, comonomer distribution is successfully modified at the level of few monomer units at a time. These polymers when converted to fine fibre structures result in formation of a unique nano-morphology and exhibit exceptional properties compared to randomly polymerized copolymers. One of the examples of such copolymer, which has been used for developing pH actuated robotic muscles, is given below: The advantages of this method are –
· Simple to implement
· Can control polymer architecture to control morphology at the nano-level
. Can be used to enhance apparently conflicting properties, such as response and mechanical properties, simultaneously
The reaction scheme
The above block copolymers have been found to have varied applications in areas-
· For making pH sensitive fibers.
· Used for making artificial muscles for use in robotics as micro actuators or as micro manipulators.
· Controlled-delivery for functional substances (drugs, nutrients, herbicides, etc).