W. Richard Bowen and Nidal Hilal 4

10. FuTuRE PRosPECTs 277
In recent years, a number of complementary measurement probes have
been integrated onto AFM tips, permitting the imaging of other properties
of a sample simultaneously with its topography. These novel developments
have included the incorporation of electrochemical, thermal, magnetic and
electronic sensors. Researchers have also found that, in addition to being
able to perform measurement functions, often these sensors allow the
controlled alteration of the local environment around the tip. Preliminary
work using certain types of sensors has shown that this feature could find
great applicability in modulating micro- and nanoenvironments of living
cells. Such functionalised probes could be incorporated into an existing
AFM system, hence significantly enhancing its capability at modest cost.
The availability of high-quality probes is also a factor limiting the uptake
of some combined techniques, such as AFM and scanning near field optical
microscopy (SNOM). The combination of super-resolution optical and
topographic imaging (AFM-SNOM) is certainly of great interest to biologists
because of the wealth of new information it could provide.
Polymers on surfaces play and will continue to play a major role in various
engineering applications such as colloidal stabilisation, lab-on-a-chip
devices, polymer composites and nanocomposites. Surprisingly, the significance
of the polymer-solid interface region has been realised only relatively
recently, and there are many gaps in our basic understanding. In nanocomposites,
the interface regions can be so extensive that they can occupy most
of the overall volume of the material even at low or moderate nanoparticle
loadings. Furthermore, the conformation and nature of entanglements of
confined polymer chains in close proximity to a solid surface can deviate
significantly from the bulk. As AFM is a real-space, high-resolution surface
technique capable of probing quantitatively both the nanostructural and
nanomechanical properties, it is likely to play an important role in the study
of the interface region in polymer composites and nanocomposites.
The self-assembly and self-organisation of polymers on solid–liquid
interfaces can be used as a generic technique for the inexpensive mass
production of surface nanostructures and nanopatterns. Many issues
remain to be elucidated by careful quantitative experimentation, and AFM
is being proven to be an indispensable tool for the study of such systems
in air or in liquids. Furthermore, the recent development of high-speed
AFM with image-acquisition times in the order of a few milliseconds is an
important development that could allow the monitoring of the mobility
of polymer chains on a solid surface and consequently the kinetic paths
of the nanostructures/nanopatterns formation. AFM offers the possibility
for systematic studies of such systems that can elucidate the underlying
physical mechanisms of the processes occurring on solid surfaces. These
studies can lead in the construction of phase/state diagrams, which may
be used for the design of well-controlled and specified surface nanostructures
for applications spanning from nanoelectronic devices to vectors for