Grafting of Functional Monomers on Biomaterials - Biointerfaces: Where Material Meets Biology - page 331

Table 11.5 (Continued)

Functional
group Reactant Comments Ref.

F F

d n 3 r 4 n g | 2

H

Solution phase reaction.
Reaction product is an
imine.

Amine
-NH 2

C

F

91, 93

O

F F

PFBA

H

Gas phase reaction.
Reaction product is an
imine.

F 3 C C

88,
96-98

O

TFBA

(CF 3 CO) 2 O
TFAA

Solution phase reaction.
Reported to also react
with carboxyl, epoxide,
and hydroxyl groups.

91, 93

TFE, trifluoroethanol; di-tBuC, di-tert-butylcarbodiimide; py, pyridine; BTFBAm, 3,5-bis-(tri-
fluoromethyl)benzyl amine; TFPH, (pentafluorophenyl)hydrazine; PFBA, penta-
fluorobenzaldehyde; TFBA, trifluoromethyl benzaldehyde; TFEA, 2,2,2-trifluoroethylamine;
TFAA, trifluoroacetic anhydride.

.

shallow depth. EDX and ATR-FTIR are often categorised as surface analysis
techniques although their penetration depth into a substrate can be as much
as microns. Other FTIR techniques will allow a more shallow depth to be
analysed (e.g., grazing angle specular reflectance technique); however, such
techniques are not used extensively in the literature for the analysis of bio-
materials as they require a very smooth substrate. It is important to recog-
nise the different penetration depths of the characterisation techniques and
often by combining date from more than one technique detailed evaluation
of the penetration depth of the graft co-polymer can be obtained, as dis-
cussed further in Section 11.3.5.
Furthermore, colorimetric methods can also be used to determine the
surface density of functional groups. 1,100 Such techniques make use of
various dyes, both those that covalently attach to a functional group (similar
to XPS probes) and those that interact via electrostatic interaction between
oppositely charged groups on the surface of the substrate and the dye
molecule. For the latter approach an assumption that a 1 : 1 interaction oc-
curs must be made. Furthermore, for acidic and basic functional groups
potentiometric titrations may be used to evaluate surface density of the
functional group. 101