Surface function, control using chemical

Surface properties are generally considered to be controlled by the outermost 0.5—1.0 nm at a polymer film (344). A logical solution, therefore, is to use self-assembled monolayers (SAMs) as model polymer surfaces. To understand fully the breadth of surface interactions, a portfoHo of chemical functionahties is needed. SAMs are especially suited for the studies of interfacial phenomena owing to the fine control of surface functional group concentration. 

In addition to the careful selection of structural metals, the cathodic protection of water-wetted parts may also be specified. For most boiler plant systems, however, because of the tortuous and extended waterside surfaces involved, the use of cathodic protection is only a partial solution to controlling corrosion and should never be the sole secondary protocol. Rather, cathodic protection functions well when employed as part of a more comprehensive program that includes appropriate internal chemical treatments. 

SAMs of alkanethiols on an Au(l 11) surface are widely used to control surface properties, electron transfer processes and to stabilize nano-clusters [6, 7]. SAMs are formed by chemical bond formation between Sand Au when an Au(l 11) substrate is immersed in a solution containing several mM of alkanethiols for hours to days. Various functions have been realized by using SAM s of alkanethiols on Au substrates as listed in Table 16.1. 

Trichlorosilane derivatives of large dye molecules are difficult to purify and owing to moisture sensitivity are hard to handle. Their organic solutions tend to become turbid rather quickly owing to the formation of insoluble polymers. Thus, solutions must be replaced frequendy. An exception may be the combination of self-assembly and surface chemical reaction (186-189,202). On the other hand, co-substituted alkyltrichlorosilane derivatives are easy to synthesize the purify. These could be used for the engineering of surface free energy through the control of chemical functionalities in their SAMs, or as active layers for attachment of biomolecules in biosensors. 

Photografting technologies, that is, the control of chemical surface functionalization by highly selective excitation with UV light, can be used for grafting to and grafting from and has been intensively explored for controlled functionalization of polymeric membranes [29]. 

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