Surface-initiated polymerization SIP

In efforts to conduct SIP from clay surfaces, Xiaowu and co-workers recently synthesized two initiators for free radical SIP, both contain quatemized amine endgroups for cation exchange with montmorillonite particles. The initiator molecule design is as follow  

7 (a) Synthetic scheme and structure of the bicationic free radical initiator, (b) Synthetic scheme and structure of the monocationic free radical initiator.  

The synthetic schemes and structures of these initiators are shown in Figs 5.7(a) and 5.7(b). They are both AIBN-analogue initiators for free radieal polymerization. The use of another symmetric bicationic azo compound, 2,2 -azobis(isobutyramidine hydrochloride) (AIBN), has also been proven to be feasible for styrene SIP on high surface area mica powder. However, no structural information for these SIP products has been reported. Asymmetric azo initiators in the form of silanes have also been successfully employed to free radically polymerize styrene from spherical silica gel surfaces. To the best of our knowledge, there have been no reports on a direct free radical SIP approach from surface-bound monocationic azo initiators on individual clay nanoparticles. 

X-ray powder diffraction patterns of the pristine clay and two initiator-intercalated clay samples are shown in Fig. 5.8. Lamellar periodicity was maintained on the organophilic clay despite the rigorous sonication-centrifugation procedure to intercalate the initiators. By using the Bragg equation, n = 2s sin 6, the d spacing values of these samples were calculated and shown beside each peak. 

The basal spacing of the pure montmorillonite Na is 1.16nm, which is in accordance with data from other sources. The XRD patterns of the intercalated clays indicate the successful insertion of the initiator molecules into the galleries 

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Fig. 9.19 Preparation of polymer brushes on solid surfaces by a) chemical grafting of end-functionalized linear polymers or selective adsorption of asymmetric block copolymers and b) by surface-initiated polymerization (SIP) using initiator functions on the solid surface. The depicted SAM bearing to-functionalities...

Advincula R. Polymer Brushes by Anionic and Cationic Surface-Initiated Polymerization (SIP). Vol. 197, pp. 107-136. 

Surface-initiated polymerization (SIP) has been carried out with a variety of initiators and Fig. 2 describes some of the most common photoinitiators [9-14]. For SIP applications, these initiators are typically modified and... 

In general, in the field of materials or condensed matter, the preparation of polymer brushes on solid surfaces is of great interest for surface modification and composite material preparation [4-6]. A number of model surface grafting techniques have been used on planar surfaces and particles and have been the subject of previous reviews. While a munber of polymer brush preparation methods have been reported using physisorption or chemisorption or so-called grafting onto methods, the emphasis of this review is on surface-initiated polymerization (SIP) methods or grafting from methods. 

The procedure normally employed in the production of PMMA-nanotube composites is the surface initiated polymerization (SIP). The initiator molecule may be tethered to the nanotube via various linkers. Bromoisobutyric acid is frequently... 

Recently, the investigation of polymer brushes has been focused on the synthesis of new tethered polymer systems primarily through surface-initiated polymerization (SIP). Previously, the term polymer brushes has been limited to the investigation of block copolymers (qv) or end-functional linear polymers that have been physically or chemically adsorbed to surfaces, respectively (3,4). Recent synthetic efforts using different polymerization mechanisms have resulted in the discovery of many novel properties of polymer brushes. This has been aided no less than the use of innovative and unique surface-sensitive analysis methods as applied to flat substrates and particles. The study of polymer brushes has benefited from improved dielectric, optical, spectroscopic, and microscopic characterization methods. Understanding the chemistry of these grafting reactions and how... 

Scheme of the preparation of solid supported planar membranes. (A) Surface initiated polymerization (SIP), and (B) solid supported polymer brush. 

Zhou Q, Fan X, Xia C, Mays J, Advincula R (2001) Living anionic surface initiated polymerization (SIP) of styrene from clay surfaces. Chem Matra-13(8) 2465-2467... 

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