Preparation of Thermoresponsive Grafted Polysilsesquioxane from Polyacrylamides Having Methoxysilyl End Group

Abstract

(3-Mercaptopropyl)trimethoxysilane was employed as a chain transfer for the polymerization of N-isopropylacrylamide (NIPAM) and N,N-dimethylacrylamide (DMAA) under UV irradiation to obtain the corresponding polymers having methoxysilyl end group. By the condensation reaction of such macrosilane coupling reagents under basic or acidic conditions, the grafted polysilsesquioxanes, which were soluble in usual organic solvents, were formed without gelation. The cocondensation of the macrosilane coupling reagents enabled the preparation of the grafted polysilsesquioxane, in which poly(NIPAM) and poly(DMAA) were introduced respectively into the polysilsesquioxane main chain. Such macrosilane coupling reagents and the grafted polysilsesquioxanes showed an amphiphilic property. Furthermore, those containing poly(NIPAM) showed reversible thermoresponsive aggregation in an aqueous solution. In the thermoresponsive phase separation measured by turbidity, no change of aggregation temperature caused by the presence of poly(DMAA) was observed.

Chain-end and backbone analysis of poly(N-isopropylacrylamide)s using sequential electron transfer dissociation and collisionally activated dissociation

“…Supplementary Material, Fig. S1), which carry a 3-mercaptopropyl triethoxysilane group at the α (initiating) chain end [37] and a 3mercaptopropanoic acid group at the ω (terminating) chain end [38], respectively. The ESI mass spectra of both samples showed singly charged [M + Na] + and doubly charged [M + 2Na] 2+ oligomers (Fig.…”

Thermoresponsive polysilsesquioxane grafted methacrylate polymer with a methoxyethylamide group

“…In the behavior of GrMEM1, an LCST of 32 1C was recorded. The effects of molecular weight of the graft chain appeared in the case of GrMEM2, which was designed to 28 In the case of the PSQ containing the analogous low-molecular-weight alkoxyethylamide group, the change required the temperature range of ca. 4 1C.…”

“…[22][23][24][25][26] Our previous efforts, in which a polymer of N-isopropylacrylamide (NIPAM) was chosen and introduced as the graft chain into PSQ backbone, focused on thermoresponsive properties and were also examples of modified hybrids. [27][28] In the graftings from PSQ, one of the findings in the grafting of poly(NIPAM) was that at least 20 monomer units of NIPAM in a graft chain were necessary to maintain a good solubility in water. Consequently, the copolymerization of NIPAM with N,N-dimethylacrylamide was required when a small number of NIPAM monomer units in one graft chain were grafted.…”