An enhancement of mid-wavelength infrared absorbance is achieved via a cost-effectively chemical method to bend the flakes by grafting two types of alkane octane (C₈H₁₈) and dodecane (C₁₂H₂₆) onto the surface terminals respectively. The chain-length of alkane exceeds the bond-length of surface functionalities Tx (=O,-OH,-F) so as to introduce intra-flake and inter-flake strains into Ti₃C₂T_x MXene. The electronic microscopy (TEM/AFM) shows obvious edge-fold and tensile/compressive deformation of flake. The alkane termination increases the intrinsic absorbance of Ti₃C₂T_x MXene from no more than 50% down to more than 99% in the mid-wavelength infrared region from 2.5 μm to 4.5 μm. Such an absorption enhancement attribute to the reduce of infrared reflectance of Ti₃C₂T_x MXene. The C-H bond skeleton vibration covers the aforementioned region and partially reduce the surface reflectance. Meanwhile, the flake deformation owing to edge-fold and tensile/compression increase the specific surface area so as to increase the absorption as well.