Part 1: Study of the orientation and isomerization of probe groups in unstretched and stretched polyolefinic films via a selective film derivatization method. Part 2: 'Latent' trialkylphosphine and trialkylphosphine oxide organogelators activated by Bro

Part 1. A general method has been developed to functionalize specifically the interior sites of polyolefinic films with chromophoric/lumophoric groups. Spectral and kinetic information have been obtained from these groups to characterize the nature of the sites and the influence of the sites on their reactivity, orientations, and photophysical properties. A comparison of linear polarizations of covalently-attached and doped 9-anthryl groups has shown that polymer crystallite surfaces (i.e., interfacial sites) but, not stretching-induced chromophore translocations, are necessary to induce non-random chromophore orientations in stretched films. The degree of orientation is determined principally by the nature and specificity of interactions of the groups with surrounding polymer chains, the reorientation of crystallites, and polymer crystallinity when the crystallinity is less than ca. 50%. Kinetics of the thermal cis-to-trans isomerizations of covalently-attached azobenzenyl groups residing in the amorphous and interfacial sites of polyethylene were indistinguishable before stretching, but two parallel, first-order rate processes were observed in the stretched films. Stretching enhances differences in polymer chain ordering, rates of relaxation, and site free volumes between the two types of sites. The effects of film stretching were sensed less strongly by azobenzene molecules doped in polyethylene because they are able to translocate and diffuse to find the sites that adapt best to their shapes and isomerization requirements.; Part 2. The abilities of zwitterions (formed from trialkylphosphines or trialkylphosphine oxides with boron trifluoride) and hydroxyphosphonium salts (formed from trialkylphosphine oxides with several strong Brønsted acids) to gel a variety of organic liquids have been examined and compared with those of the precursor phosphine oxides. The results suggest the participation of the liquids at the moment of network formation. Gel formation from the hydroxyphosphonium salts involves a competition among several concurrent processes, including salt dissociation that occurs during heating of sols and association kinetics of the salts and the phosphine oxides. A hypothesis for the role of the acid in the gelation processes and models for molecular arrangements of the gelators in the neat solids and gel networks are presented.