Intercalation and structural aspects of macroRAFT agents into MgAl layered double hydroxides

Abstract

Increasing attention has been devoted to the design of layered double hydroxide (LDH)-based hybrid materials. In this work, we demonstrate the intercalation by anion exchange process of poly(acrylic acid) (PAA) and three different hydrophilic random copolymers of acrylic acid (AA) and n-butyl acrylate (BA) with molar masses ranging from 2000 to 4200 g mol−1 synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization, into LDH containing magnesium(II) and aluminium(III) intralayer cations and nitrates as counterions (MgAl-NO3 LDH). At basic pH, the copolymer chains (macroRAFT agents) carry negative charges which allowed the establishment of electrostatic interactions with the LDH interlayer and their intercalation. The resulting hybrid macroRAFT/LDH materials displayed an expanded interlamellar domain compared to pristine MgAl-NO3 LDH from 1.36 nm to 2.33 nm. Depending on the nature of the units involved into the macroRAFT copolymer (only AA or AA and BA), the intercalation led to monolayer or bilayer arrangements within the interlayer space. The macroRAFT intercalation and the molecular structure of the hybrid phases were further characterized by Fourier transform infrared (FTIR) and solid-state 13C, 1H and 27Al nuclear magnetic resonance (NMR) spectroscopies to get a better description of the local structure.

Sulfamerazine Schiff-base complex intercalated layered double hydroxide: synthesis, characterization, and antimicrobial activity

“…The peak at 1384 cm −1 was assigned to the ν 3 vibration of NO 3 [29]. The stretching vibrations of hydroxyl groups and surface and interlayer water molecules were observed as broad and strong bands at 3451 cm −1 [23]. The bending mode of water molecules showed a weaker band at 1638 cm −1 .…”

“…Fig. 4a displays the XRD pattern of the Mg/Al-NO 3 -LDH, showing intense peaks of (d 003 ), (d 006 ), (d 009 ), (d 012 ), (d 015 ), (d 110 ), and (d 113 ) at 11°, 23°, 34°, 38°, 46°, 61°, and 62° 2θ, respectively [23, 28, 29]. The reflections indexed as the (012), (015), (110), and (113) planes indicate the development of hexagonal lattice with rhombohedral geometry.…”

“…Mg-Al-NO 3 -LDH was synthesized by using a co-precipitation method according to the reported procedure with slight modifications [22, 23, 24]. A mixed-metal nitrate solution (0.25 M Mg 2+ and 0.08 M Al 3+ ) was fine-tuned to pH 9–10 with the addition of 2 M NaOH.…”

Solid state NMR studies of layered double hydroxides

“…Other studies include using a suite of 13 C SSNMR experiments to probe C60 intercalation in MgAl-LDH [125], dynamics of dodecacyl sulfate in MgAl-LDH combined with molecular dynamics simulations [126]. The interaction between co-polymers and MgAl-LDH was studied by ultrafast 1 H MAS NMR 13 C-1 H CP-MAS and echo experiments with 1 H- 27 Al and 1 H- 13 C HETCOR using different contact times, which probed the interaction and dynamics of the co-polymers in the LDH interlayer [127], as illustrated in Fig 20. 13 C-1 H and 29 Si-1 H CPMAS combined with 27 Al MAS NMR showed the formation of Si-O-Al bonds upon surface modification of ZnAl-LDH of organo silanes [128].…”

Развитие Подходов К Формированию Платиновых Центров С Заданными Свойствами С Использованием Носителей Со Слоистой Структурой

“…Основным при исследовании структурных характеристик СДГ является метод рентгеновской дифракции. Из значений параметра кристаллической решетки с рассчитывается размер межслоевых пространств, что необходимо при изучении обменных свойств и процесса интеркалирования, а уточнение параметра а, позволяет оценить истинный катионный состав, влияющий на заряд гидроксидных слоев и их адсорбционные свойства [69,70]. Рентгеновские дифракционные спектры для СДГ различного катионного состава характеризуются присутствием серии базальных рефлексов 003 и 006, а также пиками семейства {0kl}: 012, 015, 018; {hk0}: 110 и пиком 113.…”