Polymer displays

There are three major aspects of polymer viscosity discussed in this chapter. First, we shall consider the fact that most bulk polymers display shear-dependent viscosity that is, this property does not have a single value but varies with the shearing forces responsible for the flow. Second, the molecular weight dependence of polymer viscosity is examined. We may correctly expect a... 

Polymers display Newtonian behavior = constant) at sufficiently low rates of shear [Eq. (2.29)]. 

Polymers display pseudoplasticity, with apparent viscosity decreasing as 7 increases [Eq. (2.30) and Fig. 2.2]. 

The effect of lateral methyl groups in the spacer on the phase behavior has been studied in several polybibenzoates [18,19] derived from poly(tetramethy]ene p,p bibenzoate), P4MB. The branched polymers display transition temperatures significantly lower than P4MB. Moreover, the substituents have a clear effect on the kind of mesophase formed. Thus, P4MB displays a smectic A mesophase, while the lateral methyl groups... 

For a polymer molecule, its molecular weight is the number of monomer units that it consists of multiplied by the molecular weight of the monomer unit (minus the molecular weight of any by-products of the polymerization). A molecular weight of at least 5000 is normally required before the polymer displays useful mechanical properties. 

The same authors proposed an alternative methods for obtaining soluble poly(/i-vinylborazine) homopolymers and poly(styrene-co-B-vinylborazine) copolymers 28 In fact, gentle polymerization conditions in solution at 80°C using Azobisisobutyronitrile (AIBN) (1.6 mol%) as an initiator provided soluble homopolymers. The polymer displays typical Mw and Mn values of —18,000 and 11,000, respectively, whereas an increase in the AIBN concentration results in a decrease in the molecular weight, contrary to what is usually observed in free-radical polymerization. 

Fig. 11. Gibson and coworkers synthesis of a polymer displaying the nucleobase thymine using ROMP initiated by Grubbs ruthenium complex... 

The molecular characterization of a polymeric material is a crucial step in elucidating the relationship between its properties (e.g., mechanical, thermal), its chemical structure, and its morphology. As a matter of fact, the development of a new product stems invariably from a good knowledge of the above relationships. Characterization of polymers is often a difficult task because polymers display a variety of architectures, including linear, cyclic, and branched chains, dendrimers, and star polymers with different numbers of arms. 

G Yu, G Srdanov, B Zhang, M Stevenson, J Wang, P Chen, E Baggao, J Macias, R Sun, C McPherson, P Sant, J Innocenzo, M Stainer, and M O Regan, Active-Matrix Polymer Displays Made with Electroluminescent Polymers, Cockpit Displays X, Orlando, Florida, 2003, pp. 192-199. 

At the time of this writing, few comprehensive publications exist on high-volume print technologies for organic light-emitting polymer displays. We list some of these few below as well as other places where you can get more information on the chapter topics ... 

H. Kobayashi, S. Kanbe, S. Seki, H. Kigchi, M. Kimura, I. Yudasaka, S. Miyashita, T. Shimoda, C.R. Towns, J.H. Burroughes, and R.H. Friend, A novel RGB multicolor light-emitting polymer display, Synth. Met., 111-112 125-128, 2000. 

The wavelength range for which each polymer undergoes photodimerization, the wavelength at which each polymer displays maximal sensitivity, and the sensitivity (E the minimum incident input energy per unit area required to produce an insolubilized film of the same thickness as the the initial film) are listed in Table I. Polymer sensitivities were determined for the wavelength where each polymer displays maximum sensitivity. All formulations employed the same spinning solvent and the same developer. 

Polymethacrylates containing 6-cyanouracil or 5-bromouracil units in the side chain of the polymer displayed the highest photosensitivity. Copolymers of butadiene with the methacrylate monomer with pendant 6-cyanouracil are capable of resolving 1 o features and behaved as negative photoresists. 

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