“Hydrogen-Bonded Frameworks Using Aliphatic Linkers Show High-Capacity and Reversible Water Vapor Sorption at Low Humidity” could be a title that accurately and succinctly summarizes the information in the text without using title case. However, the original text you provided, “Hydrogen-bonded frameworks composed of aliphatic linkers exhibit high-capacity and reversible water vapour sorption, even at low relative humidity,” already provides a clear and informative title.