Polymer architecture
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  • 1. An important microstructural feature of a polymer is its architecture, which relates to the way branch points lead to a deviation from a simple linear chain.A branched polymer molecule is composed of a main chain with one or more substituent side chains or branches. Types of branched polymers include star polymers, comb polymers, brush polymers, dendronized polymers, ladders, and dendrimers. A polymer's architecture affects many of its physical properties including, but not limited to, solution viscosity, melt viscosity, solubility in various solvents, glass transition temperature and the size of individual polymer coils in solution. A variety of techniques may be employed for the synthesis of a polymeric material with a range of architectures, for example Living polymerization.
  • 2. Brush polymers are a class of polymers that are adhered to a solid surface.The polymer that is adhered to the solid substrate must be dense enough so that there is crowding among the polymers which then, forces the polymers to stretch away from the surface to avoid overlapping.
  • 3. • • • • Flexible homopolymer brush Mixed homopolymer brush Random copolymer brush Block copolymer brush
  • 4.   Brush polymers can be synthesized using any of the various polymerization techniques available including: cationic, anionic , radical, ring-opening metathesis , photochemical, and electrochemical polymerization. There have also been recent advances using controlled radical polymerization (CRP) techniques such as atom transfer radical polymerization (ATRP) Brush polymers can be used in applications such as prevention of flocculation of colloidal particles, new adhesive materials, protein-resistant biosurfaces, chromatographic devices, lubricants, polymer surfactants and polymer compatabilizers.
  • 5. “grafting to” approach “grafting from” approach
  • 6. Dendrimers are repetitively branched molecules.The name comes from the Greek word "δένδρον" (pronounced dendron), which translates to "tree". Synonymous terms for dendrimer include arborols and cascade molecules.
  • 7. Dendrimers and dendrons are monodisperse and usually highly symmetric, spherical compounds. The field of dendritic molecules can be roughly divided into low-molecular weight and high-molecular weight species. The properties of dendrimers are dominated by the functional groups on the molecular surface as:water soluble, toxicity, crystallinity, tecto-dendrimer formation, and chirality.
  • 8. Divergent Methods: Convergent Methods:
  • 9. Click chemistry: Dendrimers have been prepared via click chemistry, employing Diels-Alder reactions,thiol-yne reactions and azide-alkyne reactions. An example is the synthesis of certain polyphenylene dendrimers.
  • 10.      Drug Delivery Gene Delivery Sensors Blood substitution Nanoparticles
  • 11. Dendronized polymers (or dendronised polymers) are linear polymers to every repeat unit of which dendrons are attached. Dendrons are regularly branched, tree-like fragments and for larger ones the polymer backbone is wrapped to give sausagelike, cylindrical molecular objects.
  • 12. The two main approaches into this class of polymers are the macromonomer route and the attach-to route.
  • 13.   Depending on dendron generation, the polymers differ in thickness. Neutral and charged dendronized polymers are highly soluble in organic solvents and in water, respectively. This is due to their low tendency to entangle. Dendronized polymers have been investigated for/as bulk structure control, responsivity to external stimuli, single molecule chemistry, templates for nanoparticle formation, catalysis, electro-optical devices, and bio-related applications.
  • 14.   Star polymers consist of several linear polymer chains connected at one point.Star molecules prepared by anionic polymerization had been examined prior to the development of CRP. Based on the chemical compositions of the arm species, star polymers can be classified into two categories: homo-arm (or regular) star polymers or mikto-arm (or heteroarm) star copolymers.
  • 15. THANKS FOR ATTENTION