Segregation of Amine Oxide Surfactants in PVA Films.

The vertical depth distributions of amine oxide surfactants, ,-dimethyldodecyl amine -oxide (DDAO) and ,-dimethyltetradecyl amine -oxide (DTAO), in poly(vinyl alcohol) (PVA) films were explored using neutron reflectometry (NR). In both binary and plasticized films, the two deuterated surfactants formed a single monolayer on the film surface with the remaining surfactant homogeneously distributed throughout the bulk of the film. Small-angle neutron scattering and mechanical testing revealed that these surfactants acted like plasticizers in the bulk, occupying the amorphous regions of PVA and reducing its glass-transition temperature.

Blooming of Smectic Surfactant/Plasticizer Layers on Spin-Cast Poly(vinyl alcohol) Films.

The blooming of sodium dodecyl sulfate (SDS) and the influence of plasticizer (glycerol) on the surfactant distribution in poly(vinyl alcohol) (PVA) films have been explored by neutron reflectometry (NR) and ion beam analysis techniques. When in binary films with PVA, deuterated SDS (d-SDS) forms a surface excess corresponding to a wetting layer of the surfactant molecules at the film surface. The magnitude of this surface excess increased significantly in the presence of the plasticizer, and the surfactant was largely excluded from the PVA subphase.

Surfactant and Plasticizer Segregation in Thin Poly(vinyl alcohol) Films.

The vertical depth distributions of individual additive components [cetyltrimethylammonium bromide (CTAB), deuterated pentaethylene glycol monododecyl ether (d25-C12E5), and deuterated glycerol (d-glycerol)] in PVA films have been isolated and explored by ion beam analysis techniques and neutron reflectometry. The additives display an unexpectedly rich variety of surface and interfacial behaviors in spin-cast films. In separate binary films with PVA, both d-glycerol and CTAB were evenly distributed, whereas d25-C12E5 showed clear evidence for surface and interfacial segregation.