Surface Activity of Polymers

The behaviour of polymeric polypeptides at the air/water interface was studied. Relative hydrophobicity was quantified using a Langmuir balance device designed and constructed in our laboratory (FR) according to Verger and de Haas.  

In case of branched polypeptides the increase of surface pressure was dependent on the polymer concentration and on time. 

The maximum value was recorded at polymer concentrations higher than 1.8 X 10 M after 60 min (Fig.3 and 4). It is interesting to note that while no delay of incorporation was observed for OAK and Ac-EAK, a certain period of time was needed for the appearance of polymers AK, SAK and EAK at the interface (Fig.3.). This induction time was markedly longer at low concentrations (e.g. 15 min at c = 0.9x10 Mand only 5 min at c = 4.5x10 M for SAK) (data not shown). Similar findings were described in the literature for proteins and interpreted as a need of time for an ordered structure to rearrange at the air/water interface.  

In case of polylysine the lack of change in surface pressure even at high concentration (10 M) was observed (data not shown). However data indicate that all branched polypeptides are able to form monolayers at the air/water interface. Maximal surface pressure (Jtmax) achieved has increased with pol5mier concentration and after saturation no further alteration 

Taken together these finding suggest that the surface activity of polymeric polypeptides at the air/water interface was dependent on the side chain terminal amino acid residue of polymers and can be described by the SAK AK EAK Ac-EAK OAK polylysine order. 

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The sol-gel synthesis of titanimn-silicon nanocomposites based on perfluorosulfonate ionomers was reported. Also the preparation of nanosized particles (10-50nm) derived from Ti(OR)4 and Zr(OR)4 within matrices of styrene/ 4-vinylphenol copolymer was performed via the sol-gel method. These approaches can also be used for the surface activation of polymers. For example, hydrofobic perfluorinated polymers such as polytetrafluoroethylene (PTFE) or copolymers of... 

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