Absorbed polymer layers

Water absorbing polymer layer (sodium poly(acrylic acid))... 

Over the past few years, both at the Weizmann Institute and in the Cavendish Laboratory, we have used a modification of the mica approach to measure the interaction forces F(D) between two mica surfaces,a distance D apart,immersed in organic and aqueous liquid media, both in the absence and in the presence of polymer layers absorbed onto the mica from the liquid. We have studied a number of model systems covering a wide range of conditions, using monodispersed, well characterized polymers. 

With an MLR system, linewidth variations caused by resist thickness differences can be eliminated because of the planarization step. The reflections from either topographic structures or multiple film layers can be eliminated by using an absorbant material for the bottom layer. Either an inherently absorbant polymer material can be chosen or a dye can be added... 

Quantitative determinations of the thicknesses of a multiple - layered sample (for example, two polymer layers in intimate contact) by ATR spectroscopy has been shown to be possible. The attenuation effect on the evanescent wave by the layer in contact with the IRE surface must be taken into account (112). Extension of this idea of a step-type concentration profile for an adsorbed surfactant layer on an IRE surface was made (113). and equations relating the Gibbs surface excess to the absorbance in the infrared spectrum of a sufficiently thin adsorbed surfactant layer were developed. The addition of a thin layer of a viscous hydrocarbon liquid to the IRE surface was investigated as a model of a liquid-liquid interface (114) for studies of metal extraction ( Ni+2, Cu+2) by a hydrophobic chelating agent. The extraction of the metals from an aqueous buffer into the hydrocarbon layer was monitored kinetically by the appearance of bands unique to the complex formed. 

Comprised of a swellable polymer similar to that used in the ink-absorbing base layer. 

Devices with luminescent polymer films sandwiched between high and low work function electrodes were originally fabricated to be LEDs. These same devices, however, can be operated as photodetectors or photovoltaic cells. With no externally applied bias, the polymer layer has a built-in electric field, because of the difference in work function of the two electrodes, which tilts the energy bands (Fig. VII-3). When light is absorbed by the polymer, some of the electron-hole pairs that are created are separated by the electric field. The holes are then pushed by the field to one electrode and the electrons are pushed to the other anode. The carriers that reach the electrodes provide a voltage that can either be used as a measure of the light intensity or as a source of energy. 

Since particles absorb components of the system to form adlayers (or bound polymer layers) the radius of the particle has to be corrected as follows ... 

Many other high volume consumer products make use of one or more core layers with absorbent properties. Among the most quickly and highly developed applications are baby diapers, which use super absorbent fibers. Super absorbent polymer (SAP) molecules can trap and hold hundreds to thousands of times their own weight in fluid, ultimately forming a gel. The super absorbent core layer in a diaper is between a non-woven cover stock, a one or two layer non-woven fluff/pulp sheet that takes up, distributes, and draws liquid into the core, and a microporous back sheet. In addition, elastomeric materials and waterproof elements are incorporated. The super absorbent core not only stores liquid but actively pulls moisture out of the damp or even wet fluff/ pulp, thus leaving the contact areas soft and dry. 

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