Linear photo-polymerization

Linear photo-polymerization (LPP) leads to a preferred depletion of the cinnamic side-chain molecules along due to the (2 -i- 2) cycloaddition reaction. 

A new impetus in the application of photosensitive media appeared when PVCN was discovered as an LC photoaligning substance [19]. The concept for the design of a photo-patternable hybrid linear photo-polymerizable (HLPP) configuration was proposed by Schadt et al. (Figure 5.17) [20, 21]. The HLPP layers include a linearly photo-polymerized polymer (LPP) as the aligning layer and an LPP-LCP phase retarder in one compact implementation (Figure 5.17). 

In PDLCs with weak anchoring, the drive voltage is usually low. One example is the PDLC made from E7 (from Merck) and NOA65 (Norland Optical Adhesive) by photo-polymerization-induced phase separation [27]. The cell thickness is 12 pm. The square of the drive voltage Vd is approximately linearly proportional to 1/D, as shown in Figure 11.18. 

Hyperbranched poly(ethyl methacrylate)s prepared by the photo-initiated radical polymerization of the inimer 13 were characterized by GPC with a lightscattering detector [51]. The hydrodynamic volume and radius of gyration (i g) of the resulting hyperbranched polymers were determined by DLS and SAXS, respectively. The ratios of Rg/R are in the range of 0.75-0.84, which are comparable to the value of hard spheres (0.775) and significantly lower than that of the linear unperturbed polymer coils (1.25-1.37). The compact nature of the hyperbranched poly(ethyl methacrylate)s is demonstrated by solution properties which are different from those of the linear analogs. 

While polymeric photorefractive materials can be prepared by adding separate molecules for photo-generation, charge transport and non-linear optical response into an inert polymer, most systems studied use polymers where one or more of these components are covalently bonded to the polymer. Polymer... 

TGA analyses were performed for polymer samples having different degrees of cross-linking. The decomposition of the linear oligomer starts at about 200 °C. Once cured and baked, the formed siloxane network is more thermally stable, and the decomposition begins at temperatures higher by 100-150 °C. The results are similar to those reported for analogous Tsi-modified siloxanes cross-linked by means of photo-initiated cationic polymerization of epoxides [8]. 

This polymer was synthesized via NMRP (Nitroxide Mediated Radical Polymerization) (Benoit et al. 1999) by sequential polymerization of 2VP and a mixture of NIPAAm and DMIAAm. Using the macroinitiator method, the preparation of well-defined linear block copolymers consisting of a homo polymer block P2VP (pH-sensitive) and a random copolymer block of PNlPAAm (temperamre sensitive) with DMIAAm (photo crosslinker) was possible. 

HAMA), were polymerized. Each star-block copolymer had low polydispersity and approximately five mers per arm. All the resists used were chemically amplified with a 5% photo-add generator added, and they were exposed with an e-beam in order to have a first lithographic evaluation. They found that the star resist was 20% more sensitive than the linear resist and it also exhibited a lower LER that was greater than 10% in some cases. 

The monomers were then thermally polymerized and simultaneously irradiated with linearly polarized light. Two of the monomers were able to induce bulk alignment of the liquid crystals in direction perpendicular to the polarized light. Monomer 1 was effective in concentrations as low as 1%. It was also concluded from the experimental evidence that the photo-induced bulk alignment of the ferroelectric liquid crystals may take place by a mechanism that is different from one that takes place in achiral azopolymers. 

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