Functionality hydrophilic

We have found that hydrophilic oiganic polymers treated with TiCLi have much higher etching selectivities than organosilicon polymers in an O2 plasma. This paper examines some of the parameters that influence the reaction of TiCLi with a variety of polymers. We find that TiCLi, readily functionalizes hydrophilic as well as moderately hydrophobic polymers, but fails to functionalize very hydrophobic films. Rutherford backscattering analysis reveals that TiCl4 is hydrolyzed at hydrophilic polymer surfaces that have sorbed water. Lack of surface water on hydrophobic polymers explains the absence of a TiC>2 layer on these polymer surfaces. 

TiCU readily functionalizes hydrophilic polymers such as poly(vinyl alcohol), m-ciesol novolac and methacrylic acid copolymers as well as moderately hydrophobic polymers such as poly(methyl methacrylate), poly(vinyl acetate), poly(benzyl methacrylate) and fully acetylated m-cresol novolac. HCI4 did not react with poly(styrene) to form etch resistant films indicating that very hydrophobic films follow a different reaction pathway. RBS analysis revealed that Ti is present only on the surface of hydrophilic and moderately hydrophobic polymer films, whereas it was found diffused through the entire thickness of the poly(styrene) films. The reaction pathways of hydrophilic and hydrophobic polymers with HCI4 are different because TiCl is hydrolysed by the surface water at the hydrophilic polymer surfaces to form an etch resistant T1O2 layer. Lack of such surface water in hydrophobic polymers explains the absence of a surface TiC>2 layer and the poor etching selectivities. 

Humic and fulvic acids contain various types of phenolic and carboxylic functional (hydrophilic) groups as well as aromatic and aliphatic moieties which import hydro-phobic properties to these substances. Fig. 4.12 gives a schematic idea on the composition of these substances. We refer to the book of Thurman (1985) and Aiken et al. (1985) for a description of the various properties of humic and fulvic acids in soils and waters and the book by Buffle (1988) for the coordinating properties of humus and humic acids. 

Biotransformation of xenobiotics takes place in two phases. In phase I (= functionalization reactions), reactive groups are either activated or inserted into the substance molecule, thus providing the lipophilic molecule with a functional hydrophilic group. (In phase II, a hydrophilic residue is added to this group transferases hereby catalyze the conjugation with an endogenous substance.) Phase I elfects the insertion of reactive (polar) groups (such as -OH, -COOH, -SH, -NH2) by means of four chemical processes oxidation, reduction, hydrolysis, and hydration. 

Mantovani, G., Lecolley, F., Tao, L., et al. (2005) Design and synthesis of N-maleimido-functionalized hydrophilic polymers via copper-mediated living radical polymerization A suitable alternative to PEGylation chemistry, J. Am. Chem. Soc., 127, 2%6-73. 

Qamli ST, Send S, Tuncel A. Nucleotide isolation by boronic acid functionalized hydrophilic supports. Colloid Surf. A Physicochem. Eng. Aspects 2002 207 127-137. 

Recently, packings have been developed that combine SEC properties with retentive features. The porous particles bear dual surface functionalities hydrophilic neutral groups on the outer surface and hydrophobic or ion-exchange groups on the inner surface. Proteins with a molecular weight beyond the exclusion limit... 

Self-etching (2-step) Functional and hydrophiUic addic monomers (Phenyl-P, 4-MET, 1()-MDP, MDPB and HEMA), initiator, solvents and water Functional, hydrophilic and hydrophobic monomers (Bis-GMA, TEGDMA), initiator... 

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