Complexation Controlled Growth Strategy for Preparation of Micrometer-Sized Layered Double Hydroxides for Dual-Functional Gas Barring and Antiphotoaging Applications

Layered double hydroxides (LDHs) have broad applications due to their unique compositions and structures. However, the direct preparation of micrometer-sized functional guest intercalated LDH faces huge challenges. Herein, a complexation controlled growth strategy was proposed for directly preparing micrometer-sized functional guest intercalated LDH. As a proof of concept, micrometer-sized 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (BP4) intercalated MgZnAl-LDH (BP4-LDH) with high crystallinity was successfully constructed by the strategy that makes the LDH preferentially grow along the ab two-dimensional plane. The composition, structure, and properties of BP4-LDH were systematically characterized by XRD, FT-IR, SEM, TG-DTA, BET, UV–vis, and so on. The introduction of Zn 2+ into the laminate can significantly increase the crystallinity and size of LDH, and BP4-LDH with an average particle size of 5.87 μm was prepared with a Mg:Zn:Al feeding ratio of 1.5:1.5:1. The addition of BP4-LDH can significantly improve the gas barring and antiphotoaging performance of polyurethane (PU) films. The oxygen transmission rate of PU film was reduced from 1898.0 cm 3 ·cm –2 ·day –1 to 1243.6 cm 3 ·cm –2 ·day –1 by adding 5 wt % 5.87 μm BP4-LDH. Meanwhile, the addition of BP4-LDH effectively lowered the degradation degree of C–H bonds in PU molecular chains under ultraviolet irradiation, and the decreased integral area value of C–H bonds was reduced from 58.1 to 31.3. Therefore, the prepared micrometer-sized BP4-LDH has potential applications in fields of gas barring and antiphotoaging. Meanwhile, the developed complexation controlled growth method can also be used to prepare other micrometer-sized LDH based functional materials.