Fabrication of flexible acoustic metamaterials by growing metal-organic frameworks on fabrics

As an acoustic metamaterial, Metal–organic frameworks (MOFs) can absorb sound energy abnormally. In this research, a thin and flexible acoustic material was prepared by growing MOF on the fabric. The successful growth of MIL-53(Fe) on the fiber surface was confirmed by SEM, FTIR, XRD and XPS. From the sound absorption and sound insulation test results of MIL-53(Fe)@fabric, the in-situ growth of MIL-53(Fe) greatly improves the sound absorption and sound insulation performance of the fabric, and gives the fabric an abnormal acoustic effect. From the calculation results of the theoretical model, the growth of the sub-wavelength scale MIL-53(Fe) significantly increases the flow resistance of the fabric, which is the root cause of the abnormal sound absorption of the material. It is worth noting that the sound transmission loss of the prepared flexible material doesn’t follow the mass law and exhibits excellent sound insulation performance. This is not only related to the increase in the sound energy reflected by the fabric, but also to the abnormal sound absorption of MIL-53(Fe). Here, the sound insulation performance of MOFs@fabric is reported for the first time. This work promotes the research and application of MOFs in the field of acoustics, and provides a method and theoretical basis for the design and preparation of acoustic protection textiles.