Engineering the properties of soft matter, such as natural organic or polymer based fibers or biological samples, is becoming key in the modification of the mechanical properties of fibers, in the fabrication of fibers with sensing ability, or in the creation of artificial tissues to be transplanted in the human body. Atomic layer deposition (ALD) is a promising thin film growth method capable of uniform nanoscale modification of a given substrate surface. ALD enables the conformal coating of complex 3D systems with inorganic polar and possibly metallic layers at low temperatures (less than 100 degree C), which is necessary in order to coat natural fibers or organic and biological samples without damaging or degrading them. In ALD the precursors used to supply the constituent coating material need a functionalized surface in order to react with and to release the desired species on the surface: e.g., hydroxide and methyl species can act as active sites. In this work we show that ALD is effective in coating natural or electrospun fibers. Specifically, natural fibers were coated using a series of sequential self-limiting exposures of Al(CH3)3 and H2O. The inorganic ALD coating adheres onto the fiber forming an inorganic – soft matter interface. We investigate the chemical and morphological properties of these interfaces, along with their surface energy. We also study the properties of these interfaces after processing (e.g. heat treatment in air). We anticipate that this new study may have significant impact on the implementation of inorganic coatings with biological systems via ALD, e.g., on protein-based fibrous structures like those provided by spider silk.