The impact of nanoconfinement on the crystallization and glass transition behaviors of nifedipine (NIF) has been investigated using differential scanning calorimetry. Nanoconfinement was provided by imbibing the NIF into a porous medium (controlled pore glass, CPG), and results were compared with the unconfined bulk material. Consistent with previous results from the literature, both glass transition temperature T_g and melting temperature T_m decrease with decreasing pore size. The melting temperature was found to decrease with the reciprocal of pore diameter and could be analyzed with the Gibbs–Thomson equation. In addition, for confinement sizes of 7.5 and 12 nm, it was found that no cold-crystallization occurs upon heating from the glassy state to above the expected melting transition. Finally, at intermediate confinements we find evidence of a possible new, confinement-induced polymorph of NIF.

中文翻译：

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纳米限制对硝苯地平的玻璃化转变和结晶行为的影响

纳米限制对硝苯地平（NIF）结晶和玻璃化转变行为的影响已使用差示扫描量热法进行了研究。通过将NIF吸收到多孔介质（可控孔玻璃，CPG）中来提供纳米约束，并将结果与​​未约束的散装材料进行比较。与文献先前的结果一致，玻璃化转变温度T _g和熔融温度T _m随着孔径的减小而减小。发现熔化温度随孔径的倒数而降低，可以用吉布斯-汤姆森方程进行分析。另外，对于7.5和12nm的限制尺寸，发现从玻璃态加热到高于预期的熔融转变时，没有冷结晶发生。最后，在中间限制条件下，我们发现了一种可能的，由限制条件诱导的NIF多态性的证据。