板晶界面應力的改變，可以影響於接觸晶面(contact plane)上發生的階梯式有序錯位排列(ladder-like staggering scheme of molecular packing)，即所觀察到的鏈段傾斜現象。此研究分別以三個不同的高分子系統在蒽(Anthracene)單晶上的磊晶成長(epitaxial crystallization)，來進一步瞭解在接觸晶面上的鏈段傾斜(stem tilt)現象。這三個研究方向分別是：(1)以聚乙烯分子的磊晶成長來討論與證實分子量的影響。(2)以聚乳酸分子的磊晶成長來探討基材的效應，(3)以聚丙烯分子的磊晶成長來觀察側接於主鏈上之原子團(vinyl methyl group)的影響。
觀察聚乙烯分子所進行的磊晶成長發現，接觸晶面的選擇不受分子量的影響。但是由於分子量不同，可以改變在板晶界面的鏈端密度(density of chain end)，而影響未結晶鏈段之間彼此推擠的程度。分子量的增加造成鏈端密度減少，板晶界面會更擁擠，需有較大程度的鏈段傾斜來紓解界面應力。分子量較大的聚乙烯分子，接觸晶面上鏈段傾斜的角度約為3~6°。但是低分子量的分子，卻沒有發生明確的鏈段傾斜現象。此分子量的效應進一步確認，板晶界面的應力分佈與鏈段傾斜的關係。鏈段的傾斜，也因此可以作為板晶界面應力分佈的指標。此外排列在接觸晶面的聚乙烯分子鏈段，可以選擇朝著順時針或是逆時針的方向傾斜。而延伸出基材邊緣的板晶成長，其彎曲成長的取向與鏈段傾斜的方向一致，分別發展出順時針與逆時針的彎曲形態。
觀察聚乳酸分子的磊晶成長發現，PLLA與PDLA分子均以正交晶系(orthorhombic phase)的bc晶面作為接觸晶面，與Anthracene單晶表面晶格對應(lattice match)。但是在接觸晶面上並沒有發現鏈段傾斜現象。然而之前的研究指出，在六甲基苯(hexamethylbenzene ,HMB)單晶基材上的磊晶成長，PLLA分子在同樣bc接觸晶面上，鏈段的排列有明顯的傾斜，且均朝著逆時針方向。PDLA則以較小的角度朝著順時針的方向傾斜。因此可知，即使有相同的接觸晶面，基材與未結晶鏈段的交互作用，亦可影響板晶界面上未結晶鏈段彼此之間互斥的程度，導致不同程度的界面應力，而影響鏈段排列的傾斜。觀察聚丙烯分子的磊晶成長可以發現，在固定選擇的單晶基材、結晶溫度等條件下，鏈段傾斜的程度類似於聚乙烯分子在接觸晶面的鏈段傾斜，不會因為側鏈的加入而有所改變。
分子鏈的螺旋構形會影響摺疊迴路(folding loop)所佔有的空間與在板晶界面分佈的方式，導致不同的界面應力分佈。聚乙烯及同側聚丙烯的螺旋構形不具有特定的旋光性；同側聚丙烯分子可以有左旋與右旋的螺旋構形，而聚乙烯則為Zig-Zag的分子鏈構形。對於聚乙烯及同側聚丙烯的板晶成長，鏈段傾斜及板晶彎曲的方向可以是逆時針，也可以是順時針。聚乳酸分子的螺旋構形則具有特定的旋光性；PLLA分子僅能形成左旋的的螺旋構形，與PDLA分子相反。因此聚乳酸分子的板晶成長，在接觸晶面上的鏈段排列，選擇性的朝著逆時針(PLLA)或順時針(PDLA)的方向傾斜，板晶的彎曲成長取向也隨之改變。這些實驗觀察的比較，進一步說明了分子鏈螺旋構形對界面應力分佈的影響。

The presence of lamellar surface stress is considered responsible for ladder-like staggering scheme of molecular packing on the contact plane, which is observed as the phenomenon of stem-tilt through diffraction pattern. To realize the influential factors of stem-tilt phenomenon, we studied three epitaxial crystallization systems in this research. (1) The epitaxial crystallization of polyethylene (PE) on single crystals of anthracene and hexamethylbenzene for studying the influence of molecular weight. (2) The epitaxial crystallization of polylactides (PLA) on Anthracene for studying the effect of chiral center on backbone and substrate. (3) The epitaxial crystallization of isotactic polypropylene (iPP) to discuss the influence of laterally attached group to main chain.
With selecting PE molecules of different molecular weights, results of PE epitaxial crystallization suggests that the changes in the density of chain end on basal plane according to molecular weight influences the mutual repulsion between folding loops, while the bc plane serves as the only contact plane. Increase in molecular weight caused the decrease of chain-end density and enhances the repulsion of the fold-loop on lamellar basal planes, leading to a larger extent of stem tilt. The stem-tilt degree of high molecular weight PE was statistically measured to be in the range of 3~6°. Nevertheless for lamellar growth of low molecular weight PE, stem tilt is absent. The involved orientations of stem tilt can be clockwise or counterclockwise, and for lamellar growth beyond edges of underneath substrates, correlated lamellar bending with corresponding sense was developed; clockwise stem tilting is uniquely linked to clockwise lamellar bending.
In the research of PLA epitaxial crystallization on the single crystals of hexamethylbenzene, larger stem tilt on the bc contact plane was observed with counterclockwise orientation only, while observed tilting angle of PDLA stem is smaller on the same contact plane. Since the 103 and 107 helical conformations are adopted by PDLA and PLLA respectively for crystal packing, it is conceived that helical conformation can be a significant factor for the occupied space and the distribution of fold loops on basal plane, causing the difference in the distribution of surface stress. For the epitaxial crystallization of PLA on single crystals of anthracene, both stem tilting and lamellar bending are absent. In this case, stronger interactions between substrate and PLA can be involved, which are able to reduce occupied space of fold loop and thus a lower extent of surface stress is resulted. The magnitude of stem tilt during iPP epitaxial crystallization is the same as PE on the same substrate and the same crystallization temperature. This result indicates that the laterally attached methyl group of iPP backbone cannot significantly adjust the repulsion of fold loop, or the extent of imbalanced stress distribution.
PE and iPP have no chiral center; PE is zig-zag conformation and iPP has right hand and left hand respectively. For PE and iPP, chain tilt and lamellar bending could be clockwise or counterclockwise. But PLA bears chiral centers on backbone, and PLLA only exhibits counterclockwise stem tilt and lamellar bending, whereas only clockwise stem tilt and lamellar bending for PDLA.

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