Copy files and change name with PowerShell

A friend of mine asked if I could copy files from one folder to another and rename them according to the following format

YYYYMMDDHHMMSS.ext

here  source code:

 cls  
 $source="C:\next72\source"  
 $destination="C:\next72\destination"  
 set-location  $source  
 $files=get-childitem -Recurse    
 foreach ($file in $files)  
 {  
  if (!$file.PsIsContainer)   
  {  
  $newName=$destination+"\"+[string]$file.LastWriteTime.Year +   
               [string]$file.LastWriteTime.Month +   
               [string]$file.LastWriteTime.Month +   
               [string]$file.LastWriteTime.Day +   
               [string]$file.LastWriteTime.Hour +   
               [string]$file.LastWriteTime.Minute +   
               [string]$file.LastWriteTime.Second +   
               [string]$file.Extension  
  Copy-Item $file.FullName $newName  
  }  
 }  

Then change source and destination variable in the script.