Solvent-Free Model for Self-Assembling Amphiphilic Cyclodextrins. An Off-Lattice Monte Carlo Approach in Two Dimensions

2012 ◽  
Vol 116 (9) ◽  
pp. 2687-2695 ◽  
Author(s):  
Alessandro Patti ◽  
Roland Ramsch ◽  
Conxita Solans Marsà
2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Reza Behjatmanesh-Ardakani ◽  
Maryam Farsad

Experimental data show that gemini surfactants have critical micelle concentrations that are almost tenfold lower than the CMCs of single chain ones. It is believed that the spacer groups play an important role in this subject. Short hydrophilic or long hydrophobic spacers can reduce CMC dramatically. In this paper, self-assembling processes of double-chain and one-chain surfactants with the same head to tail ratio are compared. Dimeric chain structure is exactly double of single chain. In other words, hydrophilic-lyophilic balances of two chain models are the same. Two single chains are connected head-to-head to form a dimeric chain, without introducing extra head or tail beads as a spacer group. Premicellar, micellar, and shape/phase transition ranges of both models are investigated. To do this, lattice Monte Carlo simulation in canonical ensemble has been used. Results show that without introducing extra beads as spacer group, the CMC of (H3T3)2as a dimeric surfactant is much lower than the CMC of its similar single chain, H3T3. For dimeric case of study, it is shown that bolaform aggregates are formed.


MRS Advances ◽  
2020 ◽  
Vol 5 (52-53) ◽  
pp. 2737-2749
Author(s):  
Falk Hoffmann ◽  
Rainhard Machatschek ◽  
Andreas Lendlein

AbstractMany physicochemical processes depend on the diffusion of small molecules through solid materials. While crystallinity in polymers is advantageous with respect to structure performance, diffusion in such materials is difficult to predict. Here, we investigate the impact of crystal morphology and organization on the diffusion of small molecules using a lattice Monte Carlo approach. Interestingly, diffusion determined with this model does not depend on the internal morphology of the semi-crystalline regions. The obtained insight is highly valuable for developing predictive models for all processes in semi-crystalline polymers involving mass transport, like polymer degradation or drug release, and provide design criteria for the time-dependent functional behavior of multifunctional polymer systems.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2092
Author(s):  
Panagiotis E. Theodorakis ◽  
Yongjie Wang ◽  
Aiqiang Chen ◽  
Bin Liu

Droplet nucleation and evaporation are ubiquitous in nature and many technological applications, such as phase-change cooling and boiling heat transfer. So far, the description of these phenomena at the molecular scale has posed challenges for modelling with most of the models being implemented on a lattice. Here, we propose an off-lattice Monte-Carlo approach combined with a grid that can be used for the investigation of droplet formation and evaporation. We provide the details of the model, its implementation as Python code, and results illustrating its dependence on various parameters. The method can be easily extended for any force-field (e.g., coarse-grained, all-atom models, and external fields, such as gravity and electric field). Thus, we anticipate that the proposed model will offer opportunities for a wide range of studies in various research areas involving droplet formation and evaporation and will also form the basis for further method developments for the molecular modelling of such phenomena.


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