Be Chapter 7 Part 2

Front 1

What are two classifications of surface treatments?

Back 1

physiochemical and biological modifications

Front 2

What are physiochemical treatments?

Back 2

use of physical principles or chemical reactions to alter surface composition, but does not involve active biological components and may or may not involve formation of coat

Front 3

How can surface coating be attached

Back 3

covalent or noncovalent bonds

Front 4

What is plasma discharge?

Back 4

several methods of physiochemical surface modification, some of which result in surface coatings and others do not

Front 5

What is plasma?

Back 5

assembly of species in an atomically/molecularly dissociated gaseous environment

Front 6

How is a plasma environment obtained?

Back 6

passing an electrical current through gas, the cathode is the surface to be treated. To travel from the cathode to the anode, the electrons must traverse gas in chamber and collide with molecules to form gaseous ions and radicals which react to the cathode to cause a variety of surface interactions

Front 7

In the plasma treatment what processes are occurring?

Back 7

1) competition between deposition and ablation/etching
2) cleaning/functionalization

Front 8

What occurs in deposition?

Back 8

1) Free radicals may polymerize other molecules from the gas phase onto the surface
2) small molecules may combine into larger particulates that settle on the surface

Front 9

What is functionalization?

Back 9

plasma discharge is used for cleaning or addition of hydroxyl or amine groups before further modification

Front 10

What are the advantages associated with plasma treatment?

Back 10

1) Follows shape of implant
2) Easily prepared
3) Sterile when removed from reactor
4) Low amount of leachable substances (biocompatibility)
5) Good adhesion to substrate (no delamination)

Front 11

What are some disadvantages associated with plasma treatment?

Back 11

1) The chemistry within the reactor can be ill defined
2) equipment is often expensive
3) uniform reaction within long narrow pores may be difficult
4) Care must be taken in sample preparation to prevent contamination before or after reaction