Poly(N-isopropylacrylamide)-b-poly(L-glutamic acid) (PNIPAM-b-PLGA) block copolymers were synthesised

and polymeric micelles were prepared at high temperatures.The polymeric micelles were employed to control the crystallization of calcium carbonate (CaCO3) by the gas diffusion method.Scanning electron microscopy and X-ray powder diffraction were used to study the CaCO3 morphologies and polymorphs.When the concentration of micelles is high

nest-like super-structures with diameters about 50 m were observed.The super-structures composed of aragonite fibres with large ratios of length to diameter.And droplet-like growth points were frequently found at the end of fibres.While a lower concentration of micelles led to the formation of irregular vaterite particles.From the time-resolved experiments

the mechanism of crystals formation was proposed.First

polymer-induced liquidprecursor (PILP) amorphous CaCO3 was induced by the micelles

and then the precursors grew into one-dimensional fibres through an attachingsolidifying process.For the strong interaction between copolymers and calcium ions

a higher concentration of micelles could retard crystallization of the precursors and induce the formation of aragonite fibers.While lower concentration of micelles made the crystallization less inhibited

and thus led to the formation of vaterite particles.Control experiments showed that such PILP process could not be induced by PNIPAM

PLGA homopolymers and PNIPAM-b-PLGA block copolymers dilute solution (25℃

no well defined aggregates were formed).Therefore

PNIPAM-b-PLGA micelles play a crucial role in the formation of CaCO3 liquid-like precursor precursors and aragonite fibre growth.The present investigation of the influence of PNIPAM-b-PLGA micelles on CaCO3 crystallization is helpful for the understanding of the PILP process and fabricating other fibrous inorganic materials.