The structure-property relationship of polyurethane (PU) homopolymers synthesized by the stoichiometric combination of 1,6-hexamethylene diisocyanate (HDI) and lowmolecular-weight glycols with different structure is investigated by the analysis of PU elastic modulus obtained by means of high-resolution peak force atomic force microscopy. Different experimental techniques are employed to understand the role of block structure influence on hydrogen bonding distribution, crystallinity, thermal transitions, and crystal packaging within the PU. The results show that glycols with bulky side groups have more impediments to self-assemble into hydrogen-bonded and packed macromolecular structures. (C) 2015 Wiley Periodicals, Inc.