Hydroxyapatite (HA) crystals are ubiquitous in biological systems. Therefore, these HA crystals are promising for health care applications, such as dentistry, and general material applications. Studies into the size and morphology of HA crystals have shown that these properties significantly influence their utility. Previous research shows that the formation of HA crystals are affected by the presence and characteristics of polyacrylic acid (PAA). For example, the molecular weight and architecture of PAAs, acting as a matrix, have been found to play an important role in the size, morphology and formation of HA crystals. However, the influence of end group functionalization of the polymer, especially for low molecular weight PAA, is unknown. In order to investigate the effect of the polymer end group, low molecular weight PAAs (ca. 2 kg/mol) were first prepared by light mediated atomic transfer radical polymerization. Then, the facile and scalable procedure presented in this work was used to access a library of PAAs with efficient control over the end groups by taking advantage of mild conditions and cheap reagents. The chain ends of these polymers were confirmed by ¹H NMR and their low dispersities were observed by size exclusion chromatography. Secondly, the polymers with the different end groups were assessed for their influence, on both size and morphology, in the formation of hydroxyapatite crystals. It is imagined that this could be a starting point towards biomaterials that mimic, for example, bone and teeth crystals.