Nonionizable side chains

Preferred comb polymers contain two types of side chains and are water-soluble. The first type of the side chain has moieties that ionize at the pH of the coUoidal suspension. The second type of side chain is nonionizable. Comb polymers from poly(acrylic acid) and poly(ethylene oxide) have nonionizable side chains, in addition to ionizable side chains (16). 

Therefore, the effect of nonionizable side chains will how up in limited proteolysis even though they may be undetected in titration curves. 

Proteins are complex polymers of the naturally occurring L-amino acids. The amino acids are shown in Table 2, and divided into three classes according to the characteristics of the side chain (i) hydrophobic, (if) ionizable, or (Hi) hydrophilic but nonionizable. For example, the more hydrophilic groups are those containing atoms or functional groups, which potentially are able to form hydrogen bonds (17). 

The most frequently employed solubilization approaches using nonionizable moieties involve hydroxylated and poly-oxymethylenic side chains or glucosides and their analogues. 

It should also be possible to coat silica with relatively stable nonionizable bonds formed between COOH groups and Cr ions adsorbed on the surface, especially in -the case of long chain aliphatic acids. Terminal polar end groups could be employed to modify surface polarity, and the hydrophobic bonding between parallel hydrocarbon chains attached side by side to the hydrated, CrjOrCovered surface sta bilizes the coating. 

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