Changdeng Liu

Changdeng Liu; H. Qin; Patrick T. Mather

Shape-memory polymers (SMPs) have attracted significant attention from both industrial and academic researchers due to their useful and fascinating functionality. This review thoroughly examines progress in shape-memory polymers, including the very recent past, achieved by numerous groups around the world and our own research group. Considering all of the shape-memory polymers reviewed, we identify a classification scheme wherein nearly all SMPs may be associated with one of four classes in accordance with their shape fixing and recovering mechanisms and as dictated by macromolecular details. We discuss how the described shape-memory polymers show great potential for diverse applications, including in the medical arena, sensors, and actuators.

Ronald A. Sahatjian; Francisca Tan; Patrick T. Mather; Changdeng Liu; Cheryl J. Campo

A medical device includes a balloon catheter having an expandable member, e.g., an inflatable balloon, at its distal end and a stent or other endoprosthesis. The stent is, for example, an apertured tubular member formed of a polymer and is assembled about the balloon. The stent has an initial diameter for delivery into the body and can be expanded to a larger diameter by inflating the balloon.

Changdeng Liu; Patrick T. Mather

Thermally actuated shape memory polymers (SMPs) interest, both academically and industrially, due to their ability to memorize a permanent shape that is set during processing and a temporary shape that is later programmed by manipulation above a critical temperature, either Tg or Tm. However, the thermal triggering process for SMPs is usually retarded compared to that of shape memory alloys, because the thermal conductivity of polymers is much lower (<0.30 W/m⋅K). In the present study, we incorporated a highly thermal conducting filler into a shape memory matrix to increase its thermal conductivity and therefore, shorten the heat transfer progress. A mathematical was worked out that quantitatively relates the material’s thermal conductivity with the heat transfer time, τ, also defined as a shape memory induction time. The model fit nicely with our experimental data. In addition, mechanical reinforcement was observed with the addition of this rigid thermal conducting filler.

Changdeng Liu; Seung B. Chun; Patrick T. Mather; Lei Zheng; Elisabeth H. Haley; E. Bryan Coughlin

Patrick T. Mather; Changdeng Liu; Qing Ge

Patrick T. Mather; Changdeng Liu; Cheryl J. Campo

Patrick T. Mather; Changdeng Liu

Patrick T. Mather; Byoung-Suhk Kim; Qing Ge; Changdeng Liu

Patrick T. Mather; Charles J. Burstone; Changdeng Liu

Changdeng Liu; Patrick T. Mather