End‐functionalization of polystyrene by malto‐oligosaccharide generating aggregation‐tunable polymeric reverse micelle

Abstract

AbstractThis article describes that glucose, maltose, maltotriose, maltotetraose, maltopentaose, and maltohexaose (a, b, c, d, e, and f, respectively) were introduced into the initiating chain‐end of polystyrene (PSt) through the 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO)‐mediated radical polymerization. A series of glycoconjuaged TEMPO‐adducts, 1a–f, was synthesized and used as the initiators for the polymerization of styrene (St) for 6 h at 120 °C to afford the end‐functionalized PSt's with the acetyl saccharides, 2a–f, in the yields of 37–43%. For 2a–f obtained by the polymerizations using the [St]/[1] of 125, 250, and 500, the number‐average molecular weights determined by size exclusion chromatography (SEC), Mn,SEC's, were 4800–6300, 8800–10,600, and 18,400–25,200, respectively, which fairly agreed with the predicted values. The end‐functionalized PSt's with saccharides, 3a–f, which were obtained from the deacetylation of 2a–f using sodium methoxide in dry THF, formed the polymeric reverse micelles consisting of a saccharide‐core and a PSt‐shell in chloroform and toluene. The static laser light scattering (SLS) measurements provided the average molar mass of the aggregates in toluene, Mw,SLS's, which ranged from 7.50 × 104 to 1.77 × 105 for 3a, from 1.90 × 105 to 4.93 × 105 for 3b, from 4.41 × 105 to 7.21 × 105 for 3c, from 5.85 × 105 to 8.51 × 105 for 3d, from 7.55 × 105 to 8.53 × 105 for 3e, and from 8.54 × 105 to 9.26 × 105 for 3f. The aggregation numbers, Nagg's, which were calculated from the Mw,SLS's, were from 7 to 24 for 3a, from 20 to 37 for 3b, from 34 to 89 for 3c, from 39 to 116 for 3d, from 41 to 145 for 3e, and from 31 to 146 for 3f. It was confirmed that the aggregation property, such as the Mw,SLS or Nagg values, was strongly related to the polymerization degrees of St (DP's) or the number of the glucose residues (n's) for 3a–f. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4864–4879, 2006