Our group hiking at Wissahickon Valley Park in Aug, 2022. Special thanks to Chu-Hsien for organizing this wonderful trip and those who offered rides for other people.

Congratulations on our new publication above! Please check for details at :https://pubs.acs.org/doi/10.1021/acs.jpcc.2c01214

Congratulations on our group member Chu-Hsien winning the 2022 TA award, which shows her exceptional service as a teaching assistant .

Congratulations on Sarah’s New Job at SUNY Cortland! Hope you can doing well in the future.

The density, degree of molecular orientation, and molecular layering of vapor-deposited stable glasses (SGs) vary with substrate temperature (T_dep) below the glass-transition temperature (T_g). Density and orientation have been suggested to be factors influencing the mechanical properties of SGs. We perform nanoindentation on two molecules which differ by only a single substituent, allowing one molecule to adopt an in-plane orientation at low T_dep. The reduced elastic modulus and hardness of both molecules show similar T_dep dependences, with enhancements of 15–20% in reduced modulus and 30–45% in hardness at T_dep ≈ 0.8T_g, where the density of vapor-deposited films is enhanced by ∼1.4% compared to that of the liquid-quenched glass. At T_dep < 0.8T_g, one of the molecules produces highly unstable glasses with in-plane orientation. However, both systems show enhanced mechanics. Both the modulus and hardness correlate with the degree of layering, which is similar in both systems despite their variable stability. We suggest that nanoindentation performed normal to the film’s surface is influenced by the tighter packing of the molecules in this direction.

More can be found at https://pubs.acs.org/doi/full/10.1021/acs.jpclett.2c00232.